SPECIFICATIONS FOR TRIPLE-EXPANvSION TWIN-SCREW PROPELLING ENGINES, WITH BOILERS AND AUXILIARY MACHINERY, FOR TORPEDO BOATS Nos. 3, 4, and 5, TO MAKE A SPEED OF TWENTY-FOUR AND ONE-HALF KNOTS PER HOUR AT A DISPLACEMENT OF 135 TONS. BUREAU OF STEAM ENGINEERING, WASHINGTON, D. C. WASHINGTON : GOVERNMENT PRINTING OFFICE. 1894. I LIBRARY t w OF THE Ta I University of Illinois, t ^ CIvASS. . BOOK. VOI.UMK. ^ # Q?^i.\.^.....\X'a':b.^x^r. # % Books are not to be taken from the Library. ^ ^cession No. i \ SPECIFICATIONS FOR TRIPLE-EXPANSION TWIN-SCREW PROPELLING ENGINES, WITH BOILERS AND AUXILIARY MACHINERY. FOR TORPEDO BOATS Nos. 3, 4, and 5, TO MAKE A SPEED OF TWENTY-FOUR AND ONE-HALF KNOTS PER HOUR AT A DISPLACEMENT OF 135 TONS. Ut . 5 ^BUREAU OF STEAM ENGINEERING, WASHINGTON, D. C, WASHINGTON : GOVERNMENT PRINTING OFFICE^ 1894. LIST OF PLANS ACCOMPANYING THESE SPECIFICATIONS. General arrangement of the machinery and boilers in the vessel. General arrangement of engines. High-pressure and intermediate-pressure cylinders. Low-pressure cylinders. Engine frames. Condensers. Air pumps. Circulating pumps and engines. Boiler. Note. — The following detail drawings will be furnished the contrac- tor if desired : Screw propellers. Blowers and blower engines. (n) A. Page. Air cocks, boiler — 37 Air-pressure gauges 39 Air pumps — 23 Apparatus, distilling — 40 Ash hoists 38 Ash-pit doors, furnace and 32 Ash sprinklers. 39 Attachment of valves to hulL 46 Auxiliary-engine stop valves. 46 Auxiliary exhaust pipes 42 Auxiliary feed pipes — 43 Auxiliary steam pipes — 41 B. Bars and bearers, grate 32 Bearings, crank-shaft 11 Bearings, stern-bracket 21 Bearings, stern-tube 21 Bearings, thrust 20 Bearings, valve-motion shaft. 14 Bedplates — 11 Bilge strainers 46 Bilge-suction pipes and steam ejectors 26 Bleeder pipes 42 Blowpipes 36 Blow valves, bottom 35 Blow valves, surface 35 Blower engines 39 Blowers, fire-room 39 Boilers 31 Boilers, steam gauges for 36 Boiler air cocks 37 Boiler attachments 33 Boiler casings and uptakes 32 Boiler drain cocks 37 Boiler manholes and hand- holes _ 31 Boiler material . 31 Boiler protectors, zinc 37 Boiler pumping-out pipes 36 Boiler saddles 33 Boiler stop valves 33 Boiler tubes 31 Boiler water gauges 36 Boilers and machinery, tests of 55 Bolts and nuts _ 20 Bottom blow valves 35 Boxes, journal 19 Boxes, stuffing 19 Bracket bearings, stern 21 Brasses and caps, crank-shaft. 11 Brasses, crank-pin 10 Brasses, crosshead 11 Bulkheads, shafts through 50 Bulkheads, pipes through wa- ter-tight 44 O. Casings, high and intermedi- ate pressure cylinder 3 Casings, low-pressure cylinder 4 Changes in plans and specifi- cations 59 Check valves, feed. _ 34 Chests, valve 5 Circulating-pump connec- tions __ _ 24 Circulating pumps 24 Circulating-pump engine 24 Clearances, cylinder 5 Clocks 30 Clothing and lagging 48 Cocks and valves 47 Cocks, boiler air 37 Cocks, boiler drain 37 Cocks, cylinder drain 8 Cocks, gauge 37 Condensers 22 Connecting rods 10 Connecting rods, valve 14 (III) IV Page. Connections, circulating- pump - 24 Connections, auxiliary feed pump, deck 43 Copper pipes, thickness of 44 Counters, revolution — 29 Covers, cylinder 4 Covers, valve-chest 6 Crank-pin brasses. - — 10 Crank-shaft bearings ___ 11 Crank-shaft brasses and caps. 11 Crankshafts 16 Crosshead brasses 11 Crosshead and slippers 10 Crosshead guides 12 Cylinder casings, high and in- termediate-pressure. _ 3 Cylinder casings, low-pres- sure 4 Cylinder clearances 5 Cylinder covers 4 Cylinder drain cocks 8 Cylinder relief valves — 7 Cylinders 3 Cylinders, piimp_ — 27 D. Deck and v^afcer-tight bulk- heads, pipes through 44 Deck connections from auxili- ary feed pump » 43 Description, general 1 Desk, engine-room 30 Distilling apparatus 40 Doors, furnace and ash-pit. 32 Drain cocks, boiler 37 Drain cocks, cylinder 8 Drainpipes and traps 44 Drawings of completed ma- chinery — 58 Drawings, working 57 Drips, oil 19 Dry pipes _ 33 Duplicate pieces 52 B. Ejectors, steam, and bilge-suc- tion pipes . 26 Engineer's office, superintend- ing 57 Engine, circulating-pump 24 Engine frames — H Engine indicators 20 Engine-room desk — 30 Engine-room telegraphs, _-«-- 29 Engine-room water service — 27 Engine stop valves, auxiliary. 46 Engine stop and throttle valves 8 Engine, securing, in vessel — 28 Engines, blower 39 Escape pipes — 43 Evaporators. 40 Exhaust pipes — 15 Exhaust pipes, auxiliary 42 F. Feed check valves 34 Feed pumps, main 38 Feed pumps, auxiliary. _ 38 Feed-pump pressure gauges .. 38 Feed tanks 25 Feed-tank suction pipes 26 Fire-room blowers 39 Fitting and material of pipes. 45 Floors _ --- 50 Frames , en gine __. 11 Furnace and ash-pit doors ... 32 G. Gauge cocks 37 Gauges, air-pressure 39 Gauges, boiler water 36 Gauges, feed-pump pressure. . 38 Gauges for boilers, steam 36 Gauges, steam and vacuum 28 Gear for working valves from deck - 51 Gear, lifting 51 Gear, reversing 12 Gear, turning 28 Gear, valve 12 General description. __ 1 Grate bars and bearers 32 Guides, crosshead 12 Guides, valve-stem, and wrist pin : 14 V H. Page. Hand rails - 50 Hand-holes and manholes, boiler — 31 Hose and hose attachments.. 50 High-pressure cylinder casing 3 Hoists, ash - 38 I. Indicators , en gine --- 29 Injection valves, main drain. 25 Injection valves, sea 25 Inspection 59 Instruments, labels on gear and 48 Intermediate and low pres- sure steam pipes . 43 Intermediate pressure cylin- der casings, high and 3 J. Joints, riveted 31 Journals and journal boxes.. 19 L. Labels on gear and instru- ments 48 Ladders 50 Lagging and clothing 48 Levers, working, and gear... 15 Lifting gear -- 51 Linings, valve-chest 6 Low and intermediate pres- sure steam pipes - — 43 Low-pressure cylinder casings 4 Lubrication 18 M. Machinery and boilers, tests of 55 Machinery, drawings of, com- pleted - 58 Main drain injector valves __. 25 Main valves 7 Manholes and hand-holes, boiler 31 Page, Mandrels for white-metal bearings 19 Main feed pipes 43 Main feed pumps 38 Main steam pipes. 41 Main stop valves, boiler 33 Materials and workmanship.. 53 Material, boiler 31 Material, tests of 55 Material and fitting of pipes. 45 N. Nuts and bolts 20 O. Office, superintending engi- neer's — 57 Oil drips 19 Oil tanks 51 Omissions 60 Outboard-delivery valves 25 P. Painting 56 Pipes, auxiliary feed 43 Pipes, auxiliary steam 41 Pipes, auxiliary exhaust 42 Pipes, bilge-suction — -- 26 Pipes, bleeder 42 Pipes, blow... — 36 Pipes, boiler pumping-out ... 36 Pipes, drain 44 Pipes, dry 33 Pipes, escape ._ 43 Pipes, exhaust 15 Pipes, exhaust, auxiliary 42 Pipes, feed-tank suction 26 Pipes, intermediate and low pressure steam 43 Pipes, material and fitting of. 45 Pipes, main feed 43 Pipes, main steam 41 Pipes, sea suction 26 Pipes, smoke 32 Pipes, thickness of 44 Pipes through water-tight bulkheads and deck 44 Pistons — 9 VI Piston-rod st affing boxes 9 Piston rods 9 Piston valves 7 Plans and specifications; changes in 59 Platforms, floors and 50 Platforms, w^orking 15 Preliminary tests and trials 57 Propellers, screw 21 Propeller shafts 17 Pump cylinders 27 Pump relief valves 27 Pumps, air .»> 23 Pumps, auxiliary feed 38 Pumps, circulating 24 Pumps, main feed 38 R. Radiators » 49 Record of weights 57 Rails, hand - 50 Relief valves, cylinder 7 Relief valves, pump 27 Reversing gear 12 Revolution counters 29 Riveted joints 31 Rods, connecting 10 Rods, piston 9 S. Safety valves 34 Saddles, boiler., 33 Screw propellers . 21 Sea-injection valves 25 Sea-suction pipes 26 Sea valves 46 Securing engines in vessel 28 Shafts.. 16 Shafts, crank 16 Shafts, propeller and stern tube... 17 Shafts, thrust _ 17 Shafts, through bulkheads.. _ 50 Shafts, valve-motion. 14 Smoke pipes 32 Speaking tubes 29 Specifications and plans, J in 59 Page. Sprinklers, ash 39 Steam and vacuum gauges. 28 Steam ejectors and bilge-suc- tion pipes 26 Steam gauges for boilers 36 Steam pipes, auxiliary 41 Steam pipes, main 41 Steam tube cleaners 40 Stems, valve 7 Stern-bracket bearings 21 Stern-tube bearings 21 Stern-tube shafts 17 Stern-tube stuffing boxes 21 Stop valves, boiler 33 Stop valves, auxiliary engine. 46 Strainers, bilge 46 Stuffing boxes- _. 19 Stuffing boxes, piston-rod 9 Stuffing boxes, stern-tube 21 Stuffing boxes, valve-stem ... 9 Suction pipes, bilge and steam ejectors — 26 Suction pipes, feed-tank 26 Suction pipes, sea . — 26 Superintending engineer's of- fice 57 Surface bio w v alv es.. 35 T. Tanks, feed 25 Tanks, oil 51 Telegraphs, engine-room 29 Tests and trials, preliminary. 57 Tests of boilers and machinery 55 Tests of material — 55 Thermometers 29 Thickness of copper pipes.... 44 Throttle valves, engine stop and 8 Thrust bearings 20 Thrust shafts 17 Tools 51 Trials, preliminary tests and. 57 Traps and drainpipes 44 Tubes, boiler 31 Tube cleaners, steam 40 Tube, Speaking 29 Turning gear 28 VII u. Page. TTptakes 32 V. Vacuum gauges, steam aiid__- 28 Valve chests 5 Valve-chest covers 6 Valve-chest linings 6 Valve connecting rods 14 Valve gear and reversing gear 12 Valve-motion shaft bearings__ 14 Valve-motion shafts 14 Valve-stem guides and wrist pins 14 Valve stems 7 Valve-stem stuffing boxes 9 Valves, attachment of, to hull 46 Valves, auxiliary-engine stop 46 Valves, boiler stop 33 Valves, bottom blow 35 Valves, cocks and 47 Valves, cylinder relief 7 Valves, engine stop and throt- tle 8 Valves, feed check. _ 34 Valves, gear for working from deck 51 Valves, main 7 Page. Valves, main drain injection. 25 Valve-motion shafts 14 Valves, outboard-delivery 25 Valves, piston 7 Valves, pump relief 27 Valves, safety - 34 Valves, sea _ 46 Valves, sea-injection 25 Valves, stop, auxiliary-engine 46 Valves, surface blow 35 W. Water gauges, boiler 36 Water service, engine-room. . 27 Water-tight bulkheads, pipes through _ 44 Weights, record of 57 Whistle 49 White-metal bearings, man- drels for 19 Working drawings 57 Working levers and gear 15 Working platforms 15 Workmanship and materials. 53 Z. Zinc boiler protectors 37 SPECIFIC AT [ONS ■' • i ' / ! : FOR ' ^'1 I'M 1 V <,\ ( ( f [ TRIPLE-EXPANSION TWIN-SCI^EW PROPELLING ENGINES, WITH BOILEKS AND AUXILIAEY MACHINERY, EEFERENCE BEING HAD TO THE DRAWINGS ACCOMPANYING AND FORMING PART OF THESE SPECIFICATIONS. 1. GENERAL DESCRIPTIOBT. The propelling engines will be alike and each will be placed in a separate water-tight compartment. These engines will be of the vertical inverted-cylinder, direct- acting, triple-expansion type, each with a high-pressure cylinder 12 inches in diameter, an intermediate-pressure cylinder 19^ inches in diameter, and two low-pressure cylinders each 22 inches in diameter; the stroke of all pistons being 16 inches. The indicated horse power of propelling engines will be about 2,000, when the engines are making about 412 revolutions per minute. The high- pressure cylinder will be aft in the starboard engine and forward in the port engine, and the low-pressure cylin- ders will be forward in the starboard engine and aft in the port engine. The main valves will be worked by means of cranks on a shaft parallel to the main-engine shaft and geared to that shaft. All the main valves will be piston valves, there being one for each high-pressure, two for each intermediate- pressure, and two for each low-pressure cylinder. Each main piston will have one piston rod, with a crosshead working in a slipper guide. The framing of (1) 2 the engines will consist of vertical forged-steel columns well stayed by diagonal braces. The engine bedplates will be of plate steel, supported on wrought-steel keelson- plates built in the vessel. The crank shafts will be made in one section and will be hollow. The shafts, piston rods, connecting rods, and w^orking parts generally, will be forged of mild, open-hearth steel. The piston rods, connecting rods, and valve rods will be oil tempered. There will be two condensers made entirely of composi- tion and sheet brass. Each will have a cooling surface of about 800 square feet, measured on the outside of the tubes, the water passing through the tubes. For each propelling engine there will be a single-acting air pump driven from the main-engine shaft. The circulating pumps will be of the centrifugal type, one for each con- denser. The propellers will be right and left, of man- ganese bronze or approved equivalent metal. There will be two water-tube boilers constructed for a working pressure of 250 pounds per square inch. Each boiler will be placed in a water-tight compartment as shown, one being forward of the engines and the other aft. The total grate surface will be at least 95 square feet, and the total heating surface at least 5,120 square feet. There will be two smoke pipes, one for the forward and one for the after boiler. There will be an auxiliary feed pump in each fire room, and they will be duplicates of the main feed pumps. The main feed pumps, which will be placed in the engine room, will connect with the main feed pipes, and will have a capacity sufficient to supply the amount of water necessary for the boilers when steami-ng at full power under forced draft. There w411 be one blower for each fire room. There will be two evaporators and one distiller, and such other auxiliary or supplementary machinery, tools, instruments, or apparatus as are described in the follow- ing detailed specifications, or shown in the accompanying drawings. 5864 2 3 The weight of all the machinery and boilers, including auxiliaries and heaters and water in the boilers, condens- ers, and pipes, and such stores and spare parts as may be carried on board when fully equipped must not exceed 60 tons. 2. CYLINDERS. The cylinder casings will include the valve chests, steam ports, and passages, and the various brackets to which the cylinder supports will be attached. The steam and exhaust ports will be smoothly cored to the dimen- sions shown in the drawings, the walls of the passages being strongly stayed by ribs or bolts. The four cylinder casings of each engine will be made in two castings, the high and intermediate pressure form- ing one, and the two low-pressure cylinders the other. These castings will be so bored, and flanges for secur- ing them to each other so faced, that when bolted together the distances between centers of cylinders beginning with the high-pressure will be 2o>^, 27^^, and 26>^ inches. The two castings will be bolted together by body- bound forged-steel bolts. All the cylinder casings, where bolted together or to the columns, shall be bolted by body-bound forged-steel bolts. 8. HIGH AND INTERMEDIATE PRESSURE CYLINDER CASINGS. They will be of close-grained cast iron as hard as can be properly worked, and each will contain the high and intermediate pressure cylinders of its engine. The bar- rels will be 11 inch, and the valve chests inch thick. Each will have one piston valve for the high-pressure cylinder, and two piston valves for the intermediate- pressure cylinder. They will be faced and bored, as shown, to the sizes of the cylinders, and for the valve- chest linings. The brackets at the bottom for attach- ment of the supporting columns will be well ribbed and 4 faced. There will be flanges cast on the casing, as shown, and faced for bolting it to the casing of the two low- pressure cylinders. The walls of the steam passages will be properly stayed. The lower heads will be removable. There will be facings, flanged and ribbed where neces- sary, for the attachment of the cylinder and valve-chest covers, steam pipes, exhaust pipes, receiver safety valves, peep-holes for setting valves, indicator pipes, and drain cocks. The steam passages will be pickled to remove the scale. 4. LOW-PRESSURE CYLINDER CASINGS. They will be of close-grained cast iron as hard as can be properly worked, and each will contain the two low- pressure cylinders of its engine. The barrels will be {-} inch, and the valve chests -^^ inch thick. They will be faced and bored, as shown, to the sizes of the cylinders and for the valve-chest linings. Each casing will have four piston valves, two for each low-pressure cylinder. There will be flanges cast on the casing, as shown, and faced for bolting it to the high and intermediate pressure cylinder casing. The lower heads will be removable. There will be faced brackets for the supporting columns, also facings for the cylinder and valve-chest covers, steam and exhaust pipes, receiver safety valves, receiver live-steam pipes, peep-holes for setting valves, indicator pipes, and drain cocks. The steam passages will be pickled to remove the scale. 5. CYLINDER COVERS. They will be made of cast steel, % inch finished thick- ness, and well stiffened by -fe-i^ch ribs, the flanges being inch thick. They will be so formed as to leave as lit- tle clearance as practicable. Each cover will be turned and faced to fit its cylinder, smooth turned on the inside to a template taken from the pistons, and finished on outside and edges of flanges. All except the high-pressure covers will have a facing for a relief valve. 5 The lower heads, besides being finished as above speci- fied, will be faced and bored for piston-rod stuffing boxes. The lower heads of the intermediate and two low pressure cylinders will have brackets well stiffened by ribs cast on. These brackets will be faced to form the support for the upper end of the respective crosshead guides. The covers of the high-pressure cylinder will be secured to the cylinder casing by 14, the cover of the interme- diate-pressure by 18, and the cover of each low-pressure by 18 steel studs ^ inch in diameter. Holes will be drilled and tapped for jack bolts and eye- bolts. 6. CYLINDEE CLEARANCES. Care will be taken that the clearances in the cylinders are made no larger than absolutely necessary. After the engines are set up in place and connected, the volume of the clearance at each end of each cylinder will be carefully measured by filling the space with water or oil, and the result plainly marked on some conspicuous part of the cylinder casing. Marks will also be made on the crosshead guides showing the position of the pistons when the clearances were measured. 7. VALVE CHESTS. The valve chest of each high-pressure cylinder will be fitted for one, each intermediate-pressure for two, and each low-pressure for two piston valves. There will be openings at each end of the chests for inserting and removing the valves and working linings; the chests will be accurately bored and faced for the reception of the working linings. Before the insertion of the linings the steam and exhaust passages must be thoroughly cleaned and pickled, and care taken that the passages are nowhere contracted to less than the specified areas. Each intermediate-pressure and each low-pressure valve chest will have a i>4-inch adjustable spring safety 6 valve of approved pattern. They will be loaded to loo, and 40 pounds, respectively, for the intermediate and low-pressure chests. All valve chests will also be fitted with approved composition drain cocks or valves and nonreturn valves to discharge through pipes into the feed tanks, except in the case of the low-pressure valve chests which will dis- charge into the condensers. 8. VALVE-CHEST LIHINGS. There will be a working lining at each end of each valve chest for each piston valve. They will be of close-grained cast iron as hard as can be properly worked, accurately turned to fit the casings, and accur- ately bored and polished with emery to an internal diameter of 6% inches in the high-pressure, and 7% for each of the valves of the intermediate and low pressure, leaving the body of the liners ^-^ inch thick. They will be forced into place, making all joints per- fectly tight. Both ends of each liner will have a shoulder bringing up against a shoulder in the casing at one end and against the valve-chest bonnet at the other end to insure its being held firmly in place, as shown on drawing. The steam ports will have alternating right and left diagonal bridges of such a section as to permit of the easy passage of steam, taking up not more than two- tenths of the port area. The edges of all ports will be finished to a uniform outline. 9. VALVE-CHEST COVEES. They will be made of cast brass as shown, and each, except the lower high-pressure, will be an inlet or outlet nozzle for each valve. Each lower high -pressure bonnet will be finished all over and will be bolted to a nozzle which is a continua- tion of the valve chest, and has a flange for the steam pipe. This nozzle, which will be of cast steel, ^ inch thick^ will have on it a thick facing, for bolting on the upper end 7 of the high-pressure crosshead guide. This nozzle will be fitted to the valve chesf, metal to metal, bringing up against the shoulder on the lining, and will be secured by body-bound bolts. The flanges will be turned and faced to fit on valve- chests as shown. Each lower cover will be faced and bored to receive the valve-stem stuffing boxes. All the valve chest bonnets which are also nozzles will be finished all over on the outside. There will be approved provisions for the proper oiling of the valve stems. Each valve-chest cover will be secured by eight ^-inch steel studs, with finished wrought-iron nuts. 10. MAIN VALVES. All the main valves will be piston valves, of cast iron, finished all over, the finished thickness to be as shown on the drawings. Each valve will be made with two heads or pistons, the distance between the two pistons being such as to make the steam and exhaust laps as required. The valves will not have any packing rings, but all will be turned and polished with emery to fit their cylinder liners accurately. The two heads or pistons will be held apart by a finished steel tube distance piece, upset at its ends, as shown in drawing. 11. VALVE STEMS. They will be of forged steel, oil tempered, and accu- rately' and smoothly ground where they pass through the stuffing boxes. The lower end of each stem will have an eye forged on it which will be fitted with a hard steel bushing inch thick, bored to fit the wrist pin as shown. The lower end of each high-pressure valve stem will also have a crosshead slipper forged on it to work in guides as hereinafter specified. 12. CYLINDER RELIEF VALVES. There will be an adjustable spring relief valve of inches diameter on each end of each cylinder. The valves 8 and their casings will be of composition. Pipes will lead from the relief-valve casings to the bilge with easily broken joints. These valves will have nickel seats or their equivalent, and the valve fittings will be so constructed that the valves can be easily overhauled without slacking the springs, and so that steam will not come into contact with the springs. The springs will have approved means of adjustment, and will be long enough to allow the valves to open to their full extent without unduly increas- ing the load. The valves will be guided by loosely fitting wings. The springs will bear on shoulders on spindles which fit loosely in sockets recessed in the backs of the valves. These spindles will be so fitted that the valves can be moved by the application of a lever. The valves will be fitted with casings which will prevent persons being scalded by hot water from the cylinders. Suitable fulcrums will be on casings for the application of levers for working the valves; one lever to be furnished. All springs must pass a satisfactory test. 13. CYLINDER DEATH COCKS. Each main-engine cylinder will be fitted with a i-inch asbestus-packed drain cock, placed so as to drain the cylinder thoroughly. The cocks must be perfectly tight without undue friction. The drain cocks of each cylin- der of each engine will be worked by a separate lever. All the drain cocks of the high and intermediate pressure cylinders will discharge into a pipe leading to the feed tank through nonreturn valves; of the low-pressure cyl- inders into the fresh-water side of the condensers. Small drain cocks will be fitted to the lowest parts of drain- pipes. 14. ENGINE STOP AND THROTTLE VALVES. Each engine will have a 4>^-inch approved double pop- pet valve. Each valve will have an index graduated to show the opening of the valve in tenths. These valves must be tight under all pressures, and will be worked by wheels and levers at the working platform. The valve stems and casings will be of composition. 9 15. PISTON ROD AND VALVE-STEM STUFFING BOXES. They will be made of composition, fitted with an approved metallic packing, and provided with efficient means of lubrication. The packing of each stuffing box will be made in at least two independent sections, so that in case of injury to one section the other will make a tight joint alone; this packing to be in all respects equal to the best in the market, and subject to the approval of the Bureau of Steam Engineering. There will be white metal fitted in the glands of the intermediate and low-pressure stuffing boxes, as shown. 16. PISTONS. They will be of cast or forged steel, finished all over, and will be dished. Each piston will have two packing rings, each ^ inch wide, and 3^ inch thick, of hard cast iron, cut obliquely and tongued. The packing rini>s will be sprung in without followers. There will be sufficient clearance between the piston and cylinder to allow for difference of expansion. Each piston must be carefully gauged, and care taken that the clearance between the piston and cylinder head and cover is as called for on the drawings. When completed the pistons must be carefully weighed, and no excess of weight will be allowed over that due to the dimensions shown on the drawings. 17. PISTON RODS. The piston rods will be hollow and made of forged steel, oil tempered, inches outside diameter, and i2/s inches inside diameter for the high and intermediate pressure cylinders, and if^ inches inside diameter for the low-preasure cylinders. They will be turned to fit the pistons, with shoulders as shown, and fitted each with a composition nut at piston end secured by a screw stop pin. The parallel parts will be smoothly and accurately ground. Each piston rod will have, at its seating in the piston, a shoulder /s inch deep as shown. 10 The lower ends will have the crossheads forged on as shown. The piston rod will be kept from turning in the piston by stop pins. 18. CROSSHEADS AND SLIPPERS. The crossheads will be forged on the piston rods, and each will have a steel slipper S^xio inches bolted to it and working in guides, as shown. The bearings for the connecting-rod wrist pins will be formed in the crossheads and fitted with brasses and caps, as shown. 19. CONNECTING RODS. The connecting rods, with their bolts and caps, will be 'of forged steel, finished all over, and oil tempered. They will be 40 inches long between centers, turned 2^ inches in diameter at small end and 2^ inches at large end, with a hole bored through the entire length of each, inches for the high and intermediate pressure and if^ inches for the low-pressure rods. The crosshead end of each rod will be forked to span the crosshead, and will have the crosshead pin shrunk into it. The pins will be made of forged steel, oil tempered and ground. They will be 2^ inches in diameter, 4% inches long between eyes of connecting rod, with a i^-inch hole through the axis of each. The crank pin end of each connecting rod will be fitted with brasses lined with white metal. Composition distance pieces will be fitted between the butt and crown brasses; they will be so fitted as to be removable without taking out the cap bolts, and will be channeled so as to be easily reduced when taking up lost motion. At least two thin tin liners will also be fitted to each rod for a similar purpose. The caps will each be fitted with one eyebolt for handling. 20. CRANK-PIN BRASSES. They will be accurately fitted to the connecting-rod ends and secured by the cap bolts. They will be fitted 5864 3 11 with approved white metal in strips, accurately fitted to the crank pins, and properly grooved for distribution of oil. They will be faced with sufficient clearance between crank webs to prevent nipping when heated. 21. CROSSHEAD BRASSES. They will be accurately fitted to the crosshead pin, and will be properly grooved for the distribution of oil. 22. ENGINE FRAMES. The cylinders will be supported by ten wrought-steel columns, as shown in the drawings. . , The tops of the columns will be turned and faced to tit the facings and lugs on the cylinders and will be secured as shown, and the feet of the columns will be faced to ht the facings provided for them on the pillow blocks, to which they are secured. , - ^ The columns will be stiffened by wrought-steel tie-rods, as shown. 23. BEDPLATES. They will consist each of a single ^8-inch steel plate secured to the coal-bunker bulkhead by angle iron and distance pieces, as shown, and stiffened on the top by a longitudinal angle iron on the inner edge. The mam pillow-block steel castings will be secured by bolts which will pass through the bedplate and also the engine keel- sons, and the engine columns will be bolted to facings cast on the pillow blocks. . The bedplate will be cut out for the swing of the cranks, and will rest on a yellow-pine base i inch thick, which will rest on longitudinal and transverse keelsons built in the ship. The bedplate will be firmly held by body-bound bolts passing through the bed-plate, wood and keelson plates. Where these bolts pass through the wood they will be fitted with approved cast-iron distance pieces. 24. CRANK-SHAFT BEARINGS. The pillow blocks will be made as shown, of cast steel. There will be bottom brasses only, the caps taking the 12 place of top brasses. The caps, made of cast steel, will have white metal fitted in dovetailed recesses, and the white metal will then be hammered in place ; the bottom brass, which will be turned cylindrical, v/ill be fitted with white metal similarly to the cap. The bottom brasses and the caps will be fitted with ample oil channels and faced on ends, and will be fitted to pillow blocks, as shown. They will be accurately bored to fit the journals of shaft, and the shaft will be carefully bedded. The caps for all crank shaft bearings will be secured by stud bolts of forged steel, i^s inches in diameter ; the three smaller bearings will have two bolts each and the two larger bearings four bolts each, the parts of bolts beyond the nuts will be fitted with split pins. The caps and brasses will be tapped and fitted with eyebolts for handling. After the engines are secured in the vessel the brasses and caps will be bored out in place to perfect alignment, if required. They will also be tried on their shafts and any defects made good by scraping to a proper bearing. The brasses and caps will be so fitted that the only bearing of the journals will be on the surface of the white metal. 25. CROSSHEAD GUIDES. The crosshead guides will be of the slipper type. They will be of composition, cast hollow for the circulation of water to keep them cool. At the top they will be bolted to lugs cast on the lower cylinder bonnets, except in case of the high-pressure, where they are bolted to a nozzle secured to the valve chest ; and at the bottom to a forged- steel crossbar secured to the columns as shown. The guides will be smoothly and accurately finished, and will be fitted in place to proper alignm.ent. Brass oil boxes will be provided for supplying oil to the guides. The backing guides, also cast of composition, will be bolted to flanges provided for that purpose on the go-ahead guides. 26. VALVE GEAR AND REVERSING GEAR. The valve gear will consist of a valve-motion shaft, placed on the inboard side of each engine parallel to [(^ DEPARTMENT OF and making the same number of I'^voluf^^^jthf shaft. The motion will be given to ^^^^^^^^f^lP^^;;;^ cranks on the valve-motion shafts, through varvg=@«4¥i¥e«?^ ing rods, as shown on the drawings. These shafts will be enlarged at the forward end of the port engine and after end of the starboard engine. The motion will be transmitted from, and the reversing gears placed at, the enlarged ends. On the enlarged end of each shaft will be shrunk and pinned a composition sleeve with four spiral feathers on its surface, forming part of the sleeve, and spaced at distances of 90°. The feathers must be of sufficient length to give good wearing surface. At the forward end of the fixed sleeve will be a flange, and at the after end a cap of larger diameter will be bolted to the end of the shaft, so as to limit the movement of the loose sleeve forward and aft. This loose sleeve, which will be made of steel, will have on the inside four spiral grooves equally spaced and of not less than 15 inches pitch. The grooves and the feathers on the fixed sleeve pro- vided for them must be a good working fit throughout their entire length, and must have no backlash. The loose sleeve will have on it a gear wheel, which will have a feather in the boss, so that its rotary motion will be transmitted to the loose sleeve, while the sleeve can be moved fore and aft, though the gear wheel will be firmly held by a bracket bearing. The gear must be so constructed that when the engine is going ahead or back the loose sleeve will have a tendency to remain m position fore and aft. There will be several collars on this sleeve for receiv- ing this fore-and-aft motion. These collars will fit into the bottom of a composition rack, which will have guides to insure its having only a fore-and-aft motion. Into this composition rack will mesh a quadrant gear on a horizontal shaft deriving its motion from a revers- ing lever in a vertical plane. The gears transmitting the motion from the crank shaft to the valve-motion shaft will have "herringbone" machine-cut teeth, and will be of cast steel. 5 14 27. VALVE-MOTION SHAFTS. The valve-motion shafts, of wrought steel, will be 2^ inches in diameter. They will have eight bearings each 2^ inches long and placed as shown. There will be four cranks on each valve-motion shaft, there being one in the athwartship plane of each cylin- der. The intermediate and low pressure valve cranks will have long pins with shoulders as shown. The pins will all he 2% inches diameter. The starboard shaft will be enlarged at the after end and the port one at the for- ward end to 3 inches diameter. See "Valve Gear." 28. VALVE-STEM GUIDES AND WRIST PINS. The high-pressure valve-stem crossheads will work in e4=|fM slipper guides cast on the piston-rod crosshead guides of the high-pressure cylinders. The backing guides will be of composition and will be secured in place by stud bolts as shown. The intermediate and low pressure valve stems will have no crossheads, but w411 be guided by white-metal linings in stuffing-box glands. The wrist pms will be m.ade of forged steel, hardened. They will be smoothly and accurately ground to a bear- ing 1% inches in diameter and inches long where they fit into the bushings of the valve stems. 29. VALVE CONNECTING EODS. They will be of forged steel, ^ inch thick, i inch wide at top and 1^2 inches wide at bottom. The high-pressure rods will be 37^ inches long and the interm.ediate and low-pressure rods 36^ inches long between centers of pins. The top end of each rod will be forked to span the eye of the valve stem and will have holes accurately bored in the forks to fit wrist pins as shown. The bottom ends will be T-shaped and fitted with brasses bolted thereto as shown. 30. VALVE-MOTION SHAFT BEARINGS. There will be eight of these bearings for each engine. Each will be a cast-steel pillow-block and cap, all of the 15 same pattern. The pillow block and cap will be lined with white metal. There will be proper provision for oiling. These pillow blocks will be bolted to the engine bed- plate and to the engine keelsons where possible. 31. EXHAUST PIPES, The exhaust passage from the high-pressure to the intermediate-pressure steam chest will be cast in the casing of these two cylinders ; it is of circular form and will have an internal diameter of eyi inches. The exhaust passages from the intermediate-pressure to the two low-pressure cylinders will consist of cast-brass pipes at the top and bottom, bolted on the flanges of the valve chests and taking the place of valve-chest bon- nets; they will be 7^, inches internal diameter and will be finished all over on the outside. There will be a 12-inch nozzle cast on the common ex- haust chamber of the two low-pressure cylinders, which will be connected with the condenser by a copper pipe. 32. WORKING PLATFORMS. The floors on the inboard side of each main engine will be conveniently arranged to serve as working plat- forms. The counters, revolution indicators, clocks, gauges, telegraph dials, and other engine-room fittings will be so placed near the working platforms as to be in full view while working the engines. Speaking-tube mouthpieces and telegraph levers will be conveniently placed. 33. WORKING LEVERS AND GEAR. There will be at each working platform the following hand gear, viz: One reversing lever. One stop and throttle-valve lever; bleeder-valve hand- wheel The low-pressure live-steam valve wheel. All levers will have spring latches of "locomotive pat- tern." The latches on reversing levers will be of the best type and subject to the approval of the Bureau of Steam Engineering. 16 34. SHAFTS. All the crank, line, thrust, and propeller shafts will be of forged steel. Each length will be forged solid in one piece. All shafts will be finished all over. They will be sup- ported as shown. 35. CRANK SHAFTS. The crank shaft for each propelling engine will be in one section. Each crank will have a throw of 8 inches. Each crank shaft will have a coupling disk inches thick and ii inches diameter forged on the after end. The crank pins will be 5^ inches diameter and S}4 inches long for the high and intermediate pressure, and 6^ inches long for the two low-pressure cylinders. The length of the starboard shaft will be 9 feet 10^ inches, and the length of the port shaft will be 9 feet 2^ inches. The crank webs will each be- 6 inches wide, with a thickness of 3}^ inches. The webs to be chamfered as shown on the drawing. The crank pins must be accur- ately parallel to the main journals. All journals and crank pins are to be smoothly and accurately turned and ground, and when finished will be tested and their accuracy proved. There will be holes 3^ inches in diam- eter bored axially through each crank shaft and crank pins. The cranks of the high and intermediate pres- sure cylinders will be opposite each other, and the two low-pressure cranks will be similarly placed with regard to each other. The high and intermediate pressure cranks will make an angle of 90"" with the first and second low-pressnre cranks. The sequence will then be high-pressure, second low-pressure, intermediate-pres- sure, and first low-pressure. The ends of the hole in each crank pin will be closed by a brass plate fastened on with countersunk screws. One radial %-mch hole will be drilled in each crank pin parallel to the crank and passing through the outer side of the pin only. The coupling bolts will be made of forged steel, finished to fit the holes snugly, and each fitted with wrought-iron nut and split pin. 17 36. THRUST SHAFTS. They will be 4^ inches in diameter increased to 4^ inches at the thrust collars, about 21 feet 4 inches long on the starboard side and about 11 feet 2 inches long on the port side. The shafts will be solid. Each shaft will have eight thrust collars ^ inch wide, with spaces of i ^ inches,'^the collars to be 7^ inches outside diameter. The bolt holes in the couplings will be drilled or reamed to template, and will be spaced the same as those in the crank-shaft couplings. 37. PROPELLER AND STERH-TUBE SHAFTS. The propeller shafts will each be in one section. Each will be 5 inches in diameter and will be solid. The shafts will be about 33 feet 6 inches long, cased with compo- sition 3/8 inch thick at the bearings, and elsewhere with a solid drawn brass-pipe /s inch thick. The casing will be shrunk and pinned on, and must be w^ater-tight. The casings must be accurately and smoothly turned to form journals. The joints will overlap each other about i inch and be brazed together. The coupling at the forward end must be inclosed in a brass casing, which will be secured in a satisfactory manner. The after end will enter the propeller hub about % of an inch and make a water- tight joint. The after end of the shafting will be tapered to fit the bore of the propeller boss and will be fitted for two feather keys. There will be at the forward end a steel sleeve, to form a fair water line from the end of the stern tube to the shaft. The shaft, couplings, and casings will be well coated with the same composition as the hull. The stern-tube shafts will each be about 23 feet inches long, 5 inches in diameter and will be solid. The casings will be fitted in a simJlar manner to those on the propeller shafts. 18 38. LUBRICATION. All working parts of the machinery will be fitted with approved and efficient lubricators, each with a sufficient oil capacity for four hours' running. Each lubricator to be fitted with a tube leading to the wipers on the moving parts, or tubes in the bearings and guides. Each tube from the lubricators will be fitted with a valve adjust- ment, and a sight feed with a well protected glass tube. Unions will be fitted where necessary, so that the oil pipes may be quickly taken down and cleaned, and each pipe where connected to a bearing or oil cup will have a union joint. Each main crank pin will be oiled by pipes and cups carried on its crosshead — taking oil from sight feed cups overhead; the oil to be carried to the crank pins by brass pipes through the hole of the connecting' rod. Each main crosshead journal will take oil from an overhead wick cup. Each crosshead guide will be oiled by pipes connecting with holes leading to about the middle of each forward and each backing guide. Pipes, fitted as above specified, will lead from the lubricators to the following parts of each engine: Piston rods, valve stems, valve-gear connections, and valve-mo- tion shaft bearings. As far as possible all the oil for the moving parts of each cylinder, except main bearings, will be supplied from one oil box on the cylinder with separate valve, sight feed, and pipe for each part to be oiled. All working parts for which oil cups are not specified or shown in drawings will have oiling gear of approved design, such that they can be oiled without slowing. All the oiling of each auxiliary engine will be done by one oil box where practicable. All fixed oil cups will have hinged covers^ with stops to prevent being opened too far. Moving oil cups, where necessary, will have removable covers. The supply of oil to various parts is to be easily regulated. All oil cups and their fittings, except such as are cast on 5864 4 19 tearing-s, will be of finished cast brass, or of sheet brass or copper, as may be directed, with all seams brazed. 39. OIL DRIPS. All fixed bearings will have drip cups cast on where possible, otherwise they will be of sheet brass, properly applied. All moving parts will have drip cups or pans placed where directed, and substantially made of sheet brass or copper, with brazed seams. All drip cups will have drain pipes and cocks of at least }^ inch diameter, which can be used while the engines are in operation. 40. JOURNALS AND JOURNAL BOXES. All pins which are rotary or vibratory journals will be of forged steel, hardened and ground. All pins on which the motion is vibratory will be flattened on the sides. All journals or moving parts of iron or steel will run, unless otherwise specified, in composition boxes. These boxes will be lined with approved antifriction metal where directed. All adjustable bearings will be pro- vided with channel-brass chipping pieces securely held in place and easily removable. 41. MANDRELS FOR WHITE-METAL BEARINGS. Hollow cast-iron mandrels will be furnished for form- ing the white-metal linings of crank-pin, crank-shaft, line- shaft, and thrust bearings. All these will be smoothly and accurately turned to size, and packed so as to be perfectly protected. 42. STUFFING BOXES. All iron boxes will be bushed with composition. All glands will be of composition and fitted with approved means of adjustment while the engines are in operation, and those not fitted with pinion nuts and spur rings will have lock nuts and split pins. Metallic packing, sub- ject to the approval of the Bureau of Steam Engin- eering, will be fitted in stuffing boxes of all piston rods and valve stems of main and auxiliary engines. For piston rods and valve stems the packing will be in at least two independent sections. 20 43. BOLTS AND NUTS. All bolts and nuts less than 2 inches, except in spe- cial cases, will conform to the U. S. Navy standard. All finished bolts, where directed, will be kept from turning by dowels or other suitable devices This specification is intended to apply to all pumps and auxiliary engines, as well as to parts of the main engines and boilers. The nuts of all bolts on moving parts and on pillow blocks, and elsewhere as required, will be locked, and the bolts will be fitted with split pins. 44. THRUST BEARINGS. The thrust bearings will each consist of a composition block fitted wnth a composition cap and bolted to a sole- plate which will be firmly secured to the ship. The block and cap will be cast with collar spaces and lined with white metal to fit collars on thrust shaft, and properly grooved for the distribution of oil. The block will have three pockets cored in it separ- ated by walls inch thick, the side pockets will be used for water circulation and the center pocket will form an oil trough. There will be a hole inch in- diameter, bored from the bottom of each collar space to the oil trough, and the trough will be fitted with a drain cock at one end. The cap will be jogged into the block at both sides and ends to prevent lateral motion. It will be cast with a large oil cup on top and will be cored at each side for water circulation. There will be an oil hole ^ inch in diameter leading from the oil box to each collar space. The cap will be bolted to the block by four bolts on each side, ^ inch in diameter, and will be provided with eye bolts for convenience in handling. At each end of the thrust bearing there will be a divided stuffing box and gland to prevent escape of oil. The soleplate will be of cast-steel and will be planed to fit the lower part of block. It will have lugs cast on the forward and after edges and will be fitted with steel wedges for adjusting the position of the block. The 21 block will be bolted to the soleplate by four bolts on each side, passing through oval holes in the flange of block to allow of adjustment. 45. STERN-TUBE BEARINGS. The bearings will be made of white metal run in around a mandrel of the proper size, and will not be bored. There will be a -bearing in each end, each 2 r inches long. The w^hite metal will be held from turn- ing by screws passing through the tube and entering the metal. There will be a zinc protecting ring on the outside of the after bearing. 46. STERN-TUBE STUFFING BOXES. To the forward end of each stern tube there will be riveted a composition stuffing box. The follower will be of composition. The packing spaces will be about 6 inches deep and ^ inch wide. The follower bolts will be of rolled manganese or Tobin bronze. 47. STERN-BRACKET BEARINGS. There will be two strut bearings on each side of the vessel ; each bearing will be bored out, and a tube will be fitted, and lined with white metal to form a bearing for the shaft. A zinc protecting ring will be fitted between the after strut bearing and the propeller. Each strut bearing will be fitted with a fair water line sleeve, as already specified. 48. SCREW PROPELLERS. They will be of manganese bronze or approved equiva- lent metal. The starboard propeller will be right and the port one left handed. Each boss will be accurately bored to fi_t the taper on after end of shaft and fitted with tw^o feather keys. Each propeller vAll be held on the shaft by a nut screwed on and locked in place. The shaft casing will enter about J4 inch into the propeller boss and be fitted water-tight. Each boss will be finished at the after end by a conical 22 composition cap bolted on water-tight ; the bosses and caps will be finished all over. The screw propellers will be cast as smooth as possible and polished all over. Before being placed in position on the shafts, they will be swung on a mandrel or between centers and accurately balanced by taking off the excess of metal on heavier blades. 49. CONDENSERS. There will be two cylindrical condensers, each 2 feet 7X inches outside diameter, made of sheet brass No. 11, B. W. G. The shell will be in one part as shown, and will be stiffened at center by a brass ring of T section. There will be the following openings in each condenser, each with properly faced flanges, viz : One for main exhaust pipe, 12 inches diameter; one for air-pump suction pipe, 3>4 inches diameter; one 7- inch hand-hole on top. The tube sheets will be made of composition, % inch thick, with smoothly finished holes for the tubes, tapped and fi'tted with screw glands for packing the tubes. The glands will be beaded at outer ends to prevent tubes from crawling, and will be slotted to admit a tool for screwing up. Cotton-tape packing will be used. Each condenser will contain 820 seamless drawn-brass tubes, s/^ inch outside diameter. No. 20, B. W. G., in thickness ; they will be 6 feet long between tube sheets and will be spaced if inch between centers. The cooling surface of each condenser will be about 800 square feet, measured on the outside of the tubes. The tube sheets will be secured to the flanges of the shell by naval brass or Tobin bronze bolts, which will also be used for fastening the circulating water chests ; seven of these bolts will have countersunk heads as shown to hold the tube sheet in place when the water chests are removed. The water chests at the inlet ends will be cast of com- position as shown. The outlet water chest will be made of copper No. 13, B. W. G., with composition flanges. 23 Drain cocks will be provided with pipes leading to the bilge, and all cocks to have suitable handles for working them. All bolts will be of naval brass or Tobin bronze. The condenser must be perfectly tight all over and be so proved after being secured in place. 50. AIR PUMPS. There will be one single-acting inclined trunk air pump for each engine, worked by an eccentric on the main shaft, as shown. All parts of the pumps will be of composition, except where otherwise specified or designated on drawings. Each air pump will have a cylinder of 14 inches diam- eter, with a trunk of 5 inches diameter. The pump cylinder will be cast separate, and bolted to a casing containing the foot valves. The delivery- valve chamber will be cast in one with the pump cylinder. The stroke will be 3 inches. The pump piston will be cast flanged, with a hard com- position ring sprung in, as shown. The lower quarter of the piston will be fitted to the ring so as to form a solid bearing. The ring will be cut and tongued at the upper point, and will be >^ inch thick at the bottom and % inch at the top, and will have two water grooves, as shown. There will be six foot valves, six valves in each piston, and seven delivery valves for each pump, all 3^ inches diameter, made of approved metal. Each valve will be held in place by a guard and a spiral spring of phosphor-bronze or approved equivalent metal. The valves and guards must be easily removable and held firmly in place. The gratings of the valve seats must be so arranged that the clear openings of each valve shall be at least 5^^ square inches. There will be one suction nozzle, 3% inches in diameter. Pipes, as shown, will lead from the bottom of the condenser to this* suction nozzle. There will be an air chamber fitted as shown in the drawing. This air chamber will be connected to the feed tank in engine room, 24 51. CIRCULATING PUMPS. There will be one centrifugal circulating pump for each condenser. It will discharge all around the periphery and face of the runner, directly into the water chamber of the condenser, which also forms the pump casing. The suction of the pump will be 6^ inches in diameter, with a scoop fitted on the outside of the vessel with holes having a combined area equal to twice that of the suction pipe. There will also be an opening 6 inches m diameter for a suction from the main drain. The runner of the pump will be of conical shape, hav- ing four full and four half wings, cast on as shown. The runner and wings must be perfectly smooth and have a running balance. The casing of the pump will be of composition yi inch thick, smoothly cored, with a bearing cast in it which will be lined with white metal and will have a stuffing box at the outer end of the bearing, packed with white metal. The shaft will be of i^-inch steel, covered with a brass sleeve inch thick shrunk on. The runner will be secured to the shaft by a feather key and a cap nut of brass secured by a stop pin. There will be a 3^-inch flange forged on the shaft to connect with the engine shaft. There will be suitable brackets cast on the casing for securing the engine frame. 52. CIRCULATING-PUMP ENGINE. It will be of the vertical single-cylinder type, as drawn. . The diameter of the cylinder will be 4 inches and the stroke 3 inches, and it will be fitted with a slide valve. The main shaft will be of forged steel, with a thrust bearing, as shown, which will run in white metal. It will be firmly secured to the pump-casing brackets, as shown. 53. CIRCULATING-PUMP CONNECTIONS. Each circulating pump will be fitted with pipes and valves to draw from the sea, and from the main drain, and will deliver into the condenser. 25 The injection and delivery pipes will not be less than 6% inches in diameter. There will be a nonreturn screw stop valve in the pipe leading from the niain drain to the circulating pump. All valves on circulating-pump connections will be made especially light, and the designs will be submitted to the Bureau of Steam Engineering for approval. 54. SEA-INJECTION VALVES. There will be one straightway-screw main-injection valve of not less than 6^ inches diameter for each con- denser. Each will be on the same side of the ship as its condenser. Each will have a strainer at the ship's side which will be made in the form of a scoop to throw the water through the condenser when the boat is under way. The strainer will have a sufficient number of 3^-inch holes to equal twice the area of the injection pipe. The hand- wheels of these valves must be easily accessible above the engine-room floor plates. There will be a >^-inch steam pipe leading from the auxiliary steam pipe to the injection pipe outside of the injection valve. This pipe will have a valve at each end. 55. OUTBOARB-DELIVEEY VALVES. There will be one main outboard-delivery valve for each condenser, of the same size and type as main injection valve. It v^^ill be provided with a scoop for the inflow of water when the boat is backing. 56. FEED TANKS. There will be a feed tank for each engine, placed in the adjoining fire room. Each tank will have a capacity of about 200 gallons. It will be made of No. 14, B. W. G., tinned copper, well stayed, and will be provided with screw manholes for cleaning. Each tank will have a branch tank adjoining it and placed in the engine room. This engine-room tank will be I foot square, with its top 2 feet higher than the fire- 26 room tank. They will be connected at the lowest points. The one in the engine room will have an open top, that in the fire room will have a vapor pipe. The air-pump discharge and feed-pump suction will be connected with the engine-room tank. 57. FEED-TANK SUCTION PIPES. The feed tanks will be connected by a pipe from which branches shall be led to the main and to the auxiliary feed pumps. A screw nonreturn valve will be fitted iiL each of these branches close to the pump, 58. SEA-SUCTION PIPES. A pipe will lead from the sea-suction valve in each fire room to the auxiliary feed pump in that fire room of the full size of the pump suction. Each of these pipes will be of at least the same bore as the nozzle on the pump with which it connects. Each sea suction will be con- trolled by a valve which will not permit sea water to enter any of the bilge-suction pipes or feed-tank suction pipes. 59. BILGE-SUCTION PIPES AND STEAM EJECTORS. There will be the following suction pipes from the bilge and from the drainage pipe to the various pumps: A 6-inch copper pipe will connect to each circulating pump, with a nonreturn screw stop valve close to the pump, as before specified. This pipe will connect with the main drainpipe. A copper pipe of the size of the suction nozzle of each auxiliary feed pump will connect that pump with the main drainpipe. The auxiliary feed pumps will also have suctions leading direct to the bilges if required. There will be one steam ejector, connected directly with the bilge, in each compartment where directed. These ejectors will lead through the ship's side above the water line, and will be provided with a straightway valve to prevent water running into the bilge when the boat rolls. They will connect with the auxiliary steam pipes. 5864 5 .27 Each ejector will have a capacity of 25 tons per hour The lower ends of bilge-suction pipes will be of galvan- ized iron. Care will be taken that all the copper bilge pipes are led sufficiently high to keep them out of the bilge water under ordinary circumstances. Each bilge-suction pipe must be supplied with an approved basket strainer, or its equivalent. 60. PUMP CYLINDERS. All pump cylinders, together with their valve boxes and fittings, will be made of composition. Air chambers will be fitted on the delivery sides of pumps or in the pipes, as may be directed. The water cylinders of all vertical pumps will be so arranged that the pistons are easily accessible and fitted for overhauling without disturbing the framing or piping All pumps will have packed pistons. 61. PUMP EELIEF VALVES. All feed and fire pumps will have adjustable spring relief valves of approved design connecting the delivery and suction passages. 62. ENGINE-ROOM WATER SERVICE. There will be in each engine room for each engine a i>^-inch pipe connected with a sea valve and with a special delivery from the auxiliary feed pump with branches leading to the different parts of its eneine as follows: ' Two >^-mch pipes to each crank pin; Two >^-inch pipes to each crosshead; One >4-inch pipe to each crosshead guide; One i^-inch pipe to each air-pump eccentric; One i-inch pipe to each thrust bearing; One >^-inch pipe to each crank^shaft bearing; One >^-inch pipe to each connection and bearing on valve-motion shaft; One >^-inch pipe to each circulating-pump engine; One %-inch pipe to each blower engine. 28 All of the above to have detachable sprays or short lengths of hose, as directed, and where directed to have pivoted nozzles. Each branch will have a separate valve. All the water-service pipes and fittings above the floors will be of copper No. 20, B. W. G. 63. TURNING GEAR. There will be approved gear fitted to each engine for turning it by hand. 64. SECURING ENGINES IN VESSEL. The holding-down bolts will be firmly set up and nuts locked. When finally secured, all shafting must be accurately in line with the vessel at load draft and ordinary stowage. 65. STEAM AND VACUUM GAUGES. There will be the following gauges, in polished brass cases, suitably engraved to show to what they are con- nected; all to be of approved pattern, having seamless double Bourdon tubes: One or more on each boiler, depending on type of boiler; One connected to each steam pipe in each engine room; One connected to each intermediate valve chest; One connected to each low-pressure receiver of each engine; One connected to each condenser; One on each circuit of radiator pipes near the reducing valve. All of the above will have 4>^-inch dials; those in engine room to be at the working platforms. The gauges on valve chests will be plainly marked with the limit of pressure permissible. The gauges on intermediate and low pressure valve chests will indicate both pressure and vacuum. 29 66. THERMOMETERS. There will be the following dial thermometers, all to be permanent fixtures, of approved make, and will oper- ate by the difference of expansion of two metals soldered together in a spiral spring: One on each hot well; One on each feed tank; One on each main injection pipe; One on each main outboard-delivery pipe; One on each main steam pipe close to engine. The hot-well and feed thermometers will be so fitted as to waste no feed water. 67. REVOLUTIOH COUNTERS. They will be of the continuous rotary type, to register from I to 1,000,000, each worked by positive motion; each to be in a polished brass case. There will be fitted one for each main engine. 68. EHGINE-ROOM TELEGRAPHS. A mechanical repeating telegraph of approved pattern will be fitted for each engine with its dial at the working platform, and connected to transmitters in conning tower and on deck. They shall be so placed that the handles point forward for the ahead motion. The con- nections are to be made in such manner that the chance of derangement shall be minimized. There will be an approved signal system between each engine room and its adjoining fire room and between the engine rooms. 69. SPEAKIHG TUBE. speaking tube mouthpiece will be fitted in each engine room on the bulkhead between engine rooms. 70. ENGINE INDICATORS. An indicator connection will be made to the end of each cylinder of main engines, as near as possible to the bore of the cylinder, and so as to be easily accessible. The indicator cocks will be so fitted on each cylinder of the main engines that the indicators may be connected to both ends of the cylinder; the arrangement to be approved 30 by the Bureau of Steam Engineering. The connecting pipes will be i-inch bore with easy bends. The motions of the indicator barrels, which will be inches in diameter, must be accurately coincident with the motion of the corresponding pistons, and such as to give a motion of not more than 2 inches. The gear must be approved by the Bureau of Steam. Engineer- ing, and the distance from the guide pulleys on indicator to the point for attachment of string to gear must not be more than 8 inches. Four indicators will be furnished for each engine: one for each high-pressure cylinder with two springs of 200 pounds, two of 150 pounds, and two of 100 pounds to the inch; one for each intermediate-pressure cylin- der, with two springs of 80 pounds, and two of 60 pounds to the inch; one for each low-pressure cylinder, with two springs of 40 pounds, two of 30 pounds, and two of 20 pounds to the inch. The indicators will be the best in the market, all of the same mar_ufacture and size, and with interchangeable springs, detent motion, and adjustable tension to the barrel spring, and will be subject to the approval of the Bureau of Steam Engineering. They will be nickel- plated, and will be complete with all attachments. One extra cock attachment will be furnished with each indi- cator. Each indicator will be in a separate locked case, with engraved plate, each case to be conveniently stowed. 71. ENGINE-ROOM DESK. A black-walnut hinged shelf will be provided to be used as a desk. 72. CLOCKS. There will be in each engine room, close to the counter, in a polished brass case, an eight-day clock, with 6-inch dial and a second hand. The pattern and movement to be approved by the Bureau of Steam Engineering. 73. BOILERS. There will be two boilers of the sectional, coil, or tubu- lous type. The design must be approved by the Bureau 31 of Steam Engineering. The total grate surface will be at least 95 square feet, and the total heating surface at least 5,120 square feet. The boilers must supply suffi- cient steam to run all the steam machinery on board at full power. Efficient means must be provided for o-et- tmg at the interior of such parts of the boiler as require attention for examination, cleaning, or repair. They will be built for a working pressure of at least 250 pounds per square inch. All parts of the boiler must be readily accessible for cleaning and painting. 71 BOILEE TUBES. ^ They will be made of knobbled, hammered, charcoal iron, lap-welded or drawn, or solid drawn copper, the best that can be obtained in the market, and subject to the approval of the Bureau of Steam Engineering. 75. BOILEK MATERIAL. All plates used in the construction of the boilers will be open-hearth steel. The rivets will be of open-hearth or Clapp-Griffiths steel. All material will be tested as elsewhere specified. 76. RIVETED JOINTS. If there is any riveting, in the boiler adopted, a detail ot each seam must be submitted to the Bureau of Steam Engineering. All holes must be drilled with plates in position. When the holes are drilled the plates will be separated for the purpose of removing all burrs Where possible, hydraulic riveting will be used. Seams will be calked on both sides in an approved manner. » ^ In parts where hydraulic riveting can not be used, the rivet holes will be coned and conical rivets used. 77. BOILER MANHOLES AND HAND-HOLES. There will be manholes and hand-holes wherever neces- sary for examination, repairs, and preservation of the boilers. i The manhole plates will be of cast or forged steel in dished form of approved pattern. Each plate will have a convenient handle. " S2 All plates, dogs, and nuts will be indelibly marked to show to what holes they belong. 78. FURNACE AND ASH-PIT DOORS. The furnace doors will be of approved pattern, and they must be protected from the heat of the fire. Draw- ings showing the arrangement of furnace doors must be submitted to the Bureau of Steam Engineering before work is commenced on them. There will be an automatic ash-pit door of approved design at each end of each boiler so arranged that the door at either end maybe locked when not in use. 79. GRATE BARS AND BEARERS. The grate bars for all boilers will be of wrought iron of approved pattern. The bearers will be made of ' wrought iron, supported in an approved manner. 80. BOILER CASINGS AND UPTAKES. The boiler casings will be made of wrought iron or steel of approved thickness, lined with magnesia or other suitable fireproof nonconducting material. They will be made in sections and fitted so as to be easily removable, and will have doors where necessary for cleaning. The part forming the uptake will be bolted to lower plates of smoke pipe with slotted holes to allow for ex- pansion. 81. SMOKE PIPES. There will be two smoke pipes, their tops being lo feet above the deck. Their diameters will be as shown on the drawings. They will be built of No. i6, B. W. G., iron or steel. The lower part of the pipes will be shaped to connect with the uptakes. If required, the smoke pipes will be stayed in an approved manner. Each smoke pipe will be inclosed by a casing, four inches greater in diameter than the smoke pipe. This will also be made of No. i6, B. W. G., iron or steel. The outside of the pipe and the inside of the casing will receive two coats of paint before securing them together. 33 The seams of the pipes will be lapped, those of the casings butted, with a strap on the inside, leaving the outside flush. The outside of the casings must be flush throughout. The outside appearance of the two smoke pipes must be the same. 82. BOILER SADDLES. Each boiler will rest and be secured in saddles, or be otherwise secured in an approved manner. 83. BOILER ATTACHMENTS. Each boiler will have one or more of the following attachments, as directed, depending on the type of boiler adopted, viz: Stop valves, dry pipes, main and auxiliary feed-check valves, Dottom blows, surface blows, steam gauo-es safety valves, glass water gauges of approved auto- matic closing type, gauge cocks, sentinel valves, drain cocks and air cocks, and a nozzle with a valve and a thread for attaching hose for filling boiler with water All external fittings will be of composition unless otherv^'ise directed. All fittings will be flanged and through-bolted or attached in other approved manner Ail cocks, valves, and pipes will have spigots or nipples passing through the boiler plates. 84. BOILES STOP VALVES. There will be a self-closing stop valve, with horizontal spindle, on each boiler. The valves will be bolted to the front of each boiler there being a spigot beyond the flange long enough to afford a good fastening for the dry pipe" if one is used. 85. DRY PIPES. If required by the Bureau of Steam Engineering, there will be m each boiler, as high as possible, and properly supported, a brass or tinned-copper dry pipe, extending nearly the length of the boiler, perforated on its upper side with longitudinal slits of such a number and size that the sum of their areas will equal the area of the steami pipe. 34 The valve end of the pipes will be expanded so as to fit the spigots of the stop-valve nozzles, and will be secured to them by four pins. The pipe will be closed at the inner end and have a drain hole in its under- side near each end. 86. FEED CHECK VALVES. There will be main and auxiliary check valves on each boiler. They will be placed at front ends of the boilers, and the number will be determined by the Bureau of Steam Engineering when the type of boiler has been adopted. The valve cases will be so made that the bottom of the outlet nozzle shall be at least }^ inch above the valve seat. The valves will be assisted in closing by phosphor- bronze spiral springs. These valves will have polished brass bent bar handles in lieu of handwheels. There will be a stop valve between the check valve and the boiler, but the stop valve and check valve must be in the same casing. 87. SAFETY VALVES. Each boiler will have spring safety valves of such size and number as may be determined by the Bureau of Steam Engineering, after an examination of the boiler drawings. The safety valves will be placed on the stop- valve casings, or in other approved position. There will be two valves in each casing. Each valve will have a projecting lip and an adjusta- ble ring for increasing the pressure on the valve when lifted, or an equivalent device for attaining the same result. They will be adjustable for pressure up to the test pressure — the adjusting mechanism to have an index to show the pressure at which the valve is set, and a lock to prevent tampering with the adjustment. The locks on all safety valves will be alike. The springs will be square in cross section, of first quality of spring steel, and will be nickel-plated. They will be'of such a length as to allow the valves to lift one-eighth of their diameters 5864 6 35 when the valves are set at 250 pounds pressure. They will have spherical bearings at ends, or be connected to the compression plates in such a manner as to insure a proper distribution of pressure. They will be inclosed in cases so arranged that steam will not come in contact with the springs. The spring cases will be so fitted that the- valves can be removed without slacking the springs. The valve stems will fit loosely in valves, to bottom below the level of the seats, and will be so secured that the valves may be turned by a wrench or cross bar on. top of stem. The valves will be guided by wings below and in an approved manner above. The valves will be- fitted with mechanism for lifting by hand from main deck and fire rooms. The mechanism for each pair of valves will be such that the valves will be lifted in suc- cession. All joints in the lifting gear will be composi- tion bushed. The outlet nozzle will be in the base cast- ing, so that the joint at the escape pipe will not have to be broken when taking the valves out. The casings, valves, and spindles will be made of composition. The valve seats will be solid nickel casting screwed into the top of the composition base. A drainpipe leading to the bilge will be attached to each safety-valve casing below the level of the valve seat. 88. BOTTOM BLOW VALVES. There will be i-inch composition bottom blow valves on each boiler, bolted near the front. The valves will close against the boiler pressure. If required, an inter- nal pipe will lead from each valve to near the bottom of the boiler. The number of valves is dependent upon the type of boiler adopted. 89. SURFACE BLOW VALVES. There will be i-inch surface blow valves on each boiler, if directed, bolted on or near the front. The valves will close against the boiler pressure. An internal pipe will lead from each valve to near the water line in the boiler, and will be fitted with a scum pan. The valve casing, valve hand wheel, and valve stem, will be of composition. 36 90. BLOWPIPES. A i-inch pipe will connect with the bottom blow valves in each compartment and with a sea valve in the same compartment. This pipe will have a nozzle for the con- nection of a pipe for pumping out the boilers, as well as I -inch nozzles for attachment of pipes from the surface blow valves. There will be a straightway valve in the blowpipe as near the sea valve as possible. All joints will be flange joints. 91. BOILER. PUMPING-OUT PIPES. A i-inch pipe will connect the bottom blowpipe in each compartment with the auxiliary feed pump in the same compartment, with a screw stop valve above the floor near the pump. 92. STEAM GAUGES FOE BOILERS. The steam gauges will have seamless tubes and will be of the double Bourdon tube type. They will have 6-inch dials, and will be graduated to 300 pounds. Each gauge will have an independent connection to the boiler and will be fitted with a three-way cock, and a coupling for attachment of a test gauge. The number of g'auges on each boiler will depend upon the type of boiler. 93. BOILER WATER GAUGES. The glass water gauges will be of approved automatic closing pattern, the number depending upon the type of boiler adopted, and will be determined by the Bureau of Steam Engineering. Each gauge will be placed near the front of the boiler, where it is plainly visible. The shut-off and blow-out cocks are each to have a clear opening at least Yz inch in diameter, and will be packed cocks, with levers and rods for working from fire room. The glasses will be about 12 inches in exposed length. They will be ^ inch outside diameter. The glasses will be well protected. The blow-out cocks will have drainpipes leading to bilge with union joints, % inch inside diameter. In addition to the glass water gauges there will be mica gauges, the type and number to be approved by the Bureau of Steam Engineering. 94. GAUGE COCKS. There will be asbestus-packed gauge cocks of approved pattern on each boiler, the number depending upon the type of boiler adopted, and will be determined by the Bureau of Steam Engineering. They will have rods and levers for working from fire room. Each cock will be independently attached to the boiler. They will be spaced about 4 inches vertically, the lowest one being placed where directed. Each set will have a drip pan and a %-mch copper or brass drainpipe leading to the bilge. The castings will be sufficiently strong to avoid being broken under ordinary circumstances. 95. BOILER DEAIN COCKS. Each boiler will have i-inch asbestus-packed drain cocks of approved pattern. The number and location will be determined by the Bureau of Steam Engineering when the type of boiler has been fixed. 96. BOILER AIR COCKS. Each boiler will have >^-inch air cocks. The number and location will be determined by the Bureau of Steam Engineering when the type of boiler has been fixed. 97. ZINC BOILER PROTECTORS. Each boiler will have rolled zinc plates as boiler pro- tectors. Each strap for holding zinc plates will be filed bright where in contact with zinc and boiler material. After being bolted in place the outside of the joints will be made water-tight by an approved cement. The loca- tion of zinc plates must be approved by the Bureau of Steam Engineering and there will be square feet of exposed surface, exclusive of edges, for each loa square feet of heating surface in the boilers. By means of baskets, troughs, or other approved meth- ods, the disintegrated zinc will be caught. 38 98. MAIN FEED PUMPS. There will be one main feed pump in each engine room. Each of these pumps will have a 6-inch steam cylinder, a 4-inch water cylinder, and a stroke of not less than 7 inches. They will be of the vertical type, and must be approved by the Bureau of Steam Engineering. The exhaust cushion must be adjustable. The water cylinders, water pistons, pumps, and pump rods will be of composition or bronze, and all other working parts will be of wrought iron or steel. Each main feed pump will draw water from the feed tanks, from the air-pump channel way, and from the fresh-water tanks, and will deliver into the main feed pipe and fresh-water tanks, the delivery pipe into tanks being a branch of the feed pipe with a valve in it. Each main feed pump will be bolted to the fire-room bulkhead, being placed back to back with the auxiliary feed pump in the adjoining fire room. The suction and delivery valves will be made of approved metal and must be made of ample size. 99. AUXILIARY FEED PUMPS. There will be one in each fire room. They will be duplicates of the main feed pumps. Each auxiliary feed pump will be arranged to draw from the feed tanks, the boilers, the sea, the main drain- pipe, and the bilge if required, at will; and will discharge into the boilers, the fire main, the water service pipes, or overboard through the bottom blow. 100. FEED-PUMP PEESSURE GAUGES. Each main and auxiliary feed pump will have a spring pressure gauge registering from zero to at least 350 pounds per square inch. 101. ASH HOISTS. The ashes will be hoisted by hand through the fire- room hatch. There will be a suitable arrangement for hooking block of ash whip over the hatch. 39 102. FIRE-ROOM BLOWERS. There will be one blower of approved pattern in each fire room. These blowers must be capable of supplying to the fires continuously, with ease, sufficient air to maintain the maximum rate of combustion. They will take air from the ducts, and deliver into the fire rooms. The spindle bearings must be accessible while the blow- ers are in motion, and will be of antifriction metal, fitted in composition boxes, and, together with their lubricating apparatus, must be thoroughly protected from dust. 103. BLOWER ENGINES. Each blower will be driven direct by a two-cylinder compound engine. The cranks and the two cylinders will be opposite each other, and the distance between center lines of cylinders will be as small as possible. The two cranks will have one web in common. The engine will have two cylinders of 4 inches and 6^ inches diameter, respectively, each having a stroke of 4 inches. The design must be approved by the Bureau of Steam Engineering before work is commenced on it. The lubrication must be automatic and thorough. The steam pipe for each blower will connect with the top of the auxiliary steam pipe. The shafts of blower engine will be so fitted that a portable revolution indicator can be quickly and easily applied without removing any part of the mechanism. 104. AIR-PRESSURE GAUGES. A gauge of a pattern approved by the Bureau of Steam Engineering will be fitted in each fire room to show the air pressure. These gauges will indicate pressure in inches of water. 105. ASH SPRIMKLERS. A connection with the sea-suction valve of the aux- iliary feed pump will be made in each fire room, and will be fitted with the necessary hose and coupling for wetting down ashes. 40 106. STEAM TUBE CLEANERS. A steam tube cleaner of approved design will be fitted in each fire room. Steam will be taken from the auxiliary steam pipe. Sufficient length of steam hose will be pro- vided to easily reach all the tubes. 107. DISTILLING APPAEATUS AND EVAPOEATOES. The distilling apparatus, placed where directed, will consist of two evaporators and one distiller. Each evap- orator will have a maximum capacity of 500 gallons of water per 24 hours. Tlie distiller will have a capacity of 200 gallons of potable water, at 90"" F. per 24 hours. The evaporators will be made with shells and heads of plate steel. They will be vertical, and will be subject to the approval of the Bureau of Steam Engineering. The evaporators and distillers will be so fitted and their tubes will be of such design that the tubes can be readily removed for scaling or repair, with adequate provision for expansion, and will be secured to the tube sheet m an approved manner. They will be either straight, bent, or coiled, as the Bureau of Steam Engineering may approve. The tubes of the evap- orators must be so arranged that after the system is removed from the shell it will be accessible in all its parts for scaling. The evaporators will be felted and lagged, and each will be fitted with a safety valve, steam gauge, glass water gauge, salinometer pot, and blow valve. The shell of the evaporator v/ill be tested to 50 pounds to the square inch and the coils and all parts subject to boiler pressure to 250 pounds per square inch. The distiller will be made with shell of sheet brass, flanges and heads of composition, and coils of copper or brass, thoroughly tinned on both sides. Its coil will be fitted with an inlet and outlet valve. A filter of approved design will be fitted for the dis- tiller. There will be provided a pump of approved size for each evaporator and connections will be made so that when the evaporators are connected with the condens- ers, and working under a vacuum, each pump can 41 be used to pump brine from its evaporators, the latter being fed by atmospheric pressure. When the distiller is in use, the evaporator connected with the distiller will be fed by its pump, and the brine will be blown out by the pressure in the evaporator, the same pump being used as a circulating pump for the distiller. The evaporators will be connected with the condens- ers through the auxiliary exhaust pipe. The distiller will be placed as high as possible so that the distilled water will run from the distiller to the water tanks by gravity. .... • ^t. There must be no internal detachable joints m tiie coils of either evaporator or the distiller. 108. MAIN STEAM PIPES. A lap-welded iron or seamless drawn steel pipe of approved size and thickness will connect the stop valves of the boilers in the forward and after fire rooms. The pipes will be led as may be directed, and have stop valves where shown on drawings. The flanges will be of wrought steel of approved thickness, bored, faced, and recessed, with the pipe rolled tightly into the flange and turned over to fill the recess dush with the face of the flange. The flanges will be connected by steel bolts. Straightway valves will be used where directed. 109. AUXILIARY STEAM PIPES. There will be an auxiliary steam pipe extending through engine and boiler compartments and to the windlass, ejectors, steering and blower engines, evapora- tors, torpedo air compressors and torpedo motors. It will connect with the auxiliary stop valves in both boiler compartments, and will be of sufficient size to supply all the auxiliary machinery. IE required, valves will be placed at the bulkheads and connection will be made between the main and auxiliary steam pipes as may be designated. Wherever pockets necessarily occur the pipe will be drained and trapped. All branches from the pipe to pumps or engines on a lower level will have the stop valve for such machinery close to the main pipe, 42 so that when the pump or engine is standing idle there will be noopportunity for water to collect in the vertical pipe leading to it. A separate auxiliary steam pipe, if required, will be fitted connecting the dynamo engine with the boilers; if this separate connection is required there will be a nonreturn stop valve on each boiler, and the pipes will lead as direct as possible to a separator placed near the dynamo enginesfall dips and pockets to be carefully avoided. Valves will be fitted so that the branch leading to either boiler may be shut off when the boiler is not connected with the dynamo-engine pipe, and a valve will be fitted in the pipe leading from the separator to the engine, so that the steam may be shut off from the pipe when the engine is not in use. The trap for the separator must be of the proper size, and will be fitted with by-pass pipes and valves, so that it may be cleaned without shutting steam off from the engine. There will be an approved reducing valve in the dynamo-engine steam pipe, placed as near the boilers as possible, with a steam gauge placed where directed. A plan of the piping and drains will be submitted to the Bureau of Steam Engineering for approval before any of the work is done upon it. 110. AUXILIARY EXHAUST PIPES. An auxiliary exhaust pipe, of sufficient size for all auxiliary machinery herein specified, and for such other steam machinery as may be fitted in the vessel, will be fitted and connected to all auxiliary machinery. It will have valves to direct the exhaust steam into either main exhaust pipe or into either low-pressure receiver. 111. BLEEDER PIPES. A 2-inch branch will lead from the main steam pipe in each engine room to the main exhaust pipe, with a stop valve operated from the working platform. 5864—7 43 112. INTERMEDIATE AND LOW PRESSURE STEAM PIPES. A T^-inch branch from the main steam pipe will lead to each intermediate, and a i-inch branch to each low- pressure receiver, each with a stop valve. The stop valve from the low-pressure will be worked from the starting platform. The branch to the low-pressure receiver will be fitted with a reducing valve of approved pattern set for a pressure of 20 pounds per square inch in the receiver. 113. MAIN FEED PIPES. A seamless drawn-brass pipe, iron size, of the full size of the pump discharge, will lead from each main feed pump and discharge only into a pipe leading to the main check valves on both boilers so that either pump can be used on both boilers. All parts of the pipes will be above the floors, in plain view, and all joints made by flanges screwed on the pipes and bolted together. 114. AUXILIARY FEED PIPES. A pipe similar to the main feed pipe will lead from each auxiliary feed pump to the auxiliary check valves on the boil<^r in the same compartment. 115. ESCAPE PIPES. There will be a copper pipe abaft each smoke pipe, extending as high as may be designated, finished and secured in an approved manner. This pipe will have branches leading to all the safety valves in its compart- ment. The area will equal the combined areas of the safety valves with which it is connected. 116. DECK CONNECTIONS FROM AUXILIARY FEED PUMPS. A I ^ -inch pipe will lead from the discharge of each auxiliary feed pump to the deck with a branch to the adjoining engine room. These pipes and branches will have approved straightway valves and fire plugs where directed. 44 A reverse coupling will be supplied with adapters to suit the various sizes and threads of fire hose commonly in use. 117. PIPES THEOUGH WATER-TIGHT BULKHEADS AND DECKS. They will be made water-tight by stuffing boxes, flanges, or other approved means, but the bulkhead itself must form no part of the joint. Pipes must not be led in such a manner that the angles or T's of bulkheads have to be cut. 118. DRAINPIPES AND TRAPS. All places where condensed steam can accumulate will be provided with drainpipes and cocks or valves of ample size. The lowest part of all water pipes^ and all pump cylinders and channel ways will have drain cocks with pipes where required. The handles of all drain cocks will point downward when closed. There will be an automatic trap of approved pattern for draining the radiators. 119. THICKNESS OF COPPER PIPES. The thickness of copper straight steam piping, fire ser- vice, and blow-off pipes will be found by the following formula: P X D I __rjs Where P = boiler pressure above at- ~8ooo 16" ' mosphere. D = inside diameter of pipe. T = thickness in inches. The thickness for feed-suction piping will be inch. The low-pressure exhaust pipe will be No. 12, B. W. G. All exhaust and other pipes not in the above list will be made of approved thickness. Bent copper pipes to be made from one gauge thicker material than is required for straight pipes. No bend of which the mean radius is less than one and a half times the bore of the pipe will be allowed. 45 120. MATERIAL AND FITTING OF PIPES. All pipes less than 2 inches diameter, except the lower end of bilge-suction pipes, will be of copper unless other- wise specified. All steam piping above 2 inches diameter will be made of lap-welded iron, unless otherwise specified, and size and thickness must be approved by the Bureau of Steam Engineering. The lower part of bilge-suction pipes will be of galvan- ized iron. All copper and brass piping of, and less than, 6 inches diameter will be seamless drawn. All copper pipes will have composition flanges brazed on and will have the end of the pipe expanded into a recess in the face of the flange. All feed and blow pipes will have composition flanges. All flanges of copper pipes will be in accordance with the Bureau of Steam Engineering table of thickness of pipes and flanges, the flanges being made male and female where under pressure greater than 200 pounds and faced and grooved elsewhere. The joints between flanges in steam pipes will be made with approved material. No material will be used that will not withstand the heat of the steam and keep tight an indefinite length of time, and any material used must be the best that can be procured. The Bureau of Steam Engineering must have a sched- ule of size, thickness, material, and construction of pip- ing before work is commenced on it. All composition flanges below the floor plates will be connected by bolts and nuts of rolled naval brass or Tobin bronze. All copper-pipe T pieces and fittings will be of composition, except where otherwise directed. Expansion joints of approved pattern will be fitted where required. Slip joints, if fitted, will have stop bolts and flanges. All copper pipes in bilges will be well painted, and must not rest in contact with any of the iron or steel work of the vessel. All slip joints will consist of a composition stuffing box, follower, and entering pipe, the stuffing box and entering pipe to be connected by flanges with the pipe. 46 All slip joints to be packed with metallic packing, which must be approved by the Bureau of Steam Engi- neering. 121. AUXILIAKY-ENGINE STOP VALVES. Each auxiliary engine will have stop valves in exhaust pipes as close to cylinder as possible, and in steam pipes as before specified. Exhaust stop valves will be straight- way where practicable. All pumps, except circulating pumps will have screw check valves in both suction and delivery pipes close to pump cylinders, so arranged that they may be kept ofe their seats when desired. 122. SEA VALVES. There will be the following sea valves: A main injection valve for each engine, fitted with a ^^An outboard-delivery valve for each engine, which will be fitted with a reverse scoop of the same size as that ot the main injection valve to supply the condenser when the boat is running backward; ^ A 2-inch sea valve in each fire room fitted with a scoop of sufficient size for the proper supply of auxiliary feed and fire pumps; to the chamber of this valve will be con- nected the pipe for wetting down ashes, and the suction pipe of evaporator pump. . There will also be fitted in each fire room a i-mch valve for bottom and surface blows, and the evaporator blow. There will be a valve for water service pipes placed at top of inlet water chamber of each condenser. 123. BILGE STRAINERS. The bilge connection of each auxiliary feed pump will be fitted with an approved basket or equivalent strainer above the floors. 124. ATTACHMENT OF VALVES TO HULL. Steel strengthening rings will be riveted to plating of hull around the openings for all sea valves. The valve flanges will be bolted to these rings by rolled manganese or Tobin bronze studs, care being taken not to drill the 47 holes entirely through the rings. A zinc protecting ring will be fitted in each opening in outer skin in such a man- ner as to be easil}^ renewed. All suction valves will have strainers over their open- ings on the outside of the vessel fitted as scoops in an approved manner. The details of scoops will be sub- mitted to the Bureau of Steam Engineering before work is commenced on them. These strainers will have ^-inch holes with a collective area equal to twice the area of the valve openings. Strainers must be fastened to valve pipes or casings, and not to the plates of the hull. 125. COCKS AND VALVES. All cocks and valves and their fittings, except as other- wise specified, will be of composition. All handwheels will be of finished brass, except as otherwise specified, and will be at least one and one-half times as great m diameter as their valves. All cocks communicating with vacuum spaces will have bottoms of shell cast in and have packed plugs. All cocks over i inch in diameter will have packed plugs. Reducing valves will be put m where directed or required. Valves of approved pattern wall be supplied wherever necessary to complete the various pipe systems, whether herein specified or not. All valves wull be so fitted as to be easily ground in, and be fitted where required with grinding-in guides and handles. No conical-faced valve will have a bearing on its seat of more than inch m width. All valve spindles must turn right-handed to close, and have outside threads where practicable. Cocks and valves may have, where approved, in lieu of wheels or permanent handles, removable box or socket wrenches, marked and stowed in convenient racks; these handles to be so fitted that they can only be removed when the valves are closed. All cocks and valves underneath the floor plates will have their wheels or handles above the floor plates, in easily accessible positions, unless otherwise directed. The sizes of valves as given in these specifications will refer to the diameter of the equivalent clear openings. 48 126. LABELS ON GEAE AND INSTRUMENTS. All cocks will have engraved brass plates to show their uses and to indicate whether open or shut. All valves, except such as may be otherwise directed, will have sim- ilarly engraved plates to show their uses, or have the same plainly engraved on nandwheels. . •-, i All hand levers or their quadrants will be similarly marked. Gear for working valves from deck will be marked as elsewhere specified. All steam stop valves will have indices to show to what extent they are opened. . i AU gauges, thermometers, counters, telegraph dials, - speakinp--tube annunciators, and revolution indicators will be suitably engraved to show to what they are con- nected. . -Ill 1 All engraving will be deep and be filled m with black cement. 127. CLOTHING AND LAGGING. The main cvlinders and valve chests, excepting cylin- der heads, after being finally secured in place m the ves- sel and tested, will be covered with approved incombus- tible nonconducting material and neatly lagged with Russia iron all over, secured with polished brass bands and round-headed brass screws. The upper cylinder heads will be covered with sheet brass lagging 3-^ inch thick, with a sheet of asbestus board beneath it. All lagging will be so secured as to be easily removed, replaced, and repaired. . . ^ All parts of the condensers except the water chests at ends will be clothed with approved material put on m sections so as to be easily removed and replaced and neatly lagged with Russia sheet iron secured by brass bands. , . ... All steam and exhaust pipes and all steam valves will be clothed in an approved manner with a satisfactory nonconducting material, covered with No. 6 canvas; this canvas to be sewed on and be well painted, ihe main steam pipes in engine room and the separator will 49 be also covered with approved covering. The canvas covering of steam pipes will be secured to bulkheads where the pipes pass through them. The steam cylinders of all auxiliary engines will be clothed the same as main cylinders and will be lagged with Russia iron. 128. RADIATORS. Radiators of approved patterns, with such areas as may be called for in the specifications for radiators to be furnished by the Bureau of Steam Engineering, will be furnished and fitted and connected. All radiators will be fitted with approved valves, with valve-stem guards, and removable keys for valve stems. The ends of the stems will be triangular in cross sections. The steam and drain pipes will be of seamless drawn brass, of iron-pipe size, suitably connected by composi- tion fittings in a manner that will permit them to be easily taken down for repairs. All union joints will be coned or have corrugated cop- per washers. All holes through bulkheads will be thimbled. Steam and drain pipes will be clothed where near woodwork, and elsewhere as required. At a point just before the steam pipes branch out for- ward and aft an adjustable reducing valve of approved .design will be fitted. The drain pipe of all the circuits will have an approved automatic steam trap discharging into feed tank, and elsewhere as directed. 129. WHISTLE. An approved polished brass steam whistle, with a bell of about 2 inches diameter, will be placed forward of the forward smoke pipe, well above the level of the awnings, and connected to the auxiliary steam pipe by a pipe hav- ing a stop valve at its lower end and a working valve at the upper end. If directed a drainpipe with valve will lead to the feed tank. 50 130. HOSE AND ATTACHMENTS. Fifty feet of hose will be supplied for each engine room and each fire room. The hose will be of the best quality rubber-lined linen, all 1^2 inches diameter, with coup- lings. Each hose will be supplied with an approved ^-inch nozzle. A pair of spanners will be supplied for each hose nozzle. Hose nozzles and spanners will be fitted in beckets. 131. SHAFTS THROUGH BULKHEADS. All shafts passing through water-tight bulkheads will be fitted with stuffing boxes, each in two parts. 132. FLOOES. The fire rooms will be floored with wrought-iron plates ys inch thick, with neatly matched fiat-top corrugations running fore and aft. The plates will be of convenient size and easily removable. They will rest on proper ledges of angle or T iron, and will have drain holes where necessary. In place of floors approved gratings will be used in the engine rooms. 133. LADDERS. Ladders will be fitted wherever necessary for reaching the engine rooms and fire rooms from deck, and elsewhere if necessary. All ladders w^ill be so fitted as to be easily removable where required, and will be joined and hinged, with neces- sary fastenings and gear, where they have to be moved when closing hatches. 134. HAND RAILS. Hand rails and all necessary dash and protection plates, easily removable where required, will be fitted to all ladders and around moving parts of machin- ery, and will be secured in an approved manner. The hand rails will be made of brass tubing of diameter and thickness to be approved, and will be polished all over. The dash and protection plates will be made of steel or iron neatly finished with polished brass bands. 5864 8 51 135. GEAR FOR WORKING VALVES FROM DECK. The safety valves, boiler stop valves, and engine-room stop valves, will have suitable gear for working them from the main deck. 136. LIFTING GEAR. Wherever required, holes will be tapped and eyebolts or other approved means provided for handling parts of machinery. 137. OIL TANKS. Oil tanks of loo gallons total capacity, will be fitted' and divided as may be directed, with facilities for filling from deck. They will be made of galvanized wrought iron, and will each have a hand-hole and cover near the top, and a locked cock for drawing oil. The tanks will be galvanized after being built. All oil tanks will- be fitted with drip pans. 138. TOOLS. The following tools will be furnished in addition to those elsewhere specified: One set of wrenches complete for each engine and each fire room, to be fitted for all nuts in their respective com- partments, plainly marked with sizes, and fitted in irorL racks of approved pattern. The wrenches for nuts of bolts less than i inch in diameter will be finished, and: for all over 2 inches in diameter will be box wrenches,, where such can be used. Socket wrenches wiU be fur- nished where required. Open-end wrenches will be of steel or wrought iron with case-hardened jaws, all others of wrought iron or cast steel. Fixed trammels or gauges for aligning crank shafts, brass pins being let into pillow blocks and center marked for this purpose. Two complete sets of fire tools for each fire room. Four coal and four ash buckets for each fire room. All trammels and gauges will have protecting cases. All tools will be conveniently stowed. 52 139. DUPLICATE PIECES. The following duplicate pieces, in addition to others specified, will be furnished, fitted, and ready for use, viz: One set of valves and springs for each pump; One set of valve guards and bolts for one air pump; One set of valve guards and bolts for one feed pump; One set of bottom brasses for crank-shaft bearings; One crank shaft for each engine to be fitted in place, protected in an approved manner; One propeller for each engine, and thc}^ will be of such pattern as may be directed after the trial of the vessel; One complete set of brasses for each main-engine valve gear, so that all the brasses can be replaced at one time; One complete set of brasses for each circulating-pump engine, each main feed pump, each auxiliary feed pump, and each blowing engine; One piston rod for each size pump; One feed check valve complete; One bottom blow valve complete; One surface blow valve complete; One complete set of metallic packing for each size stuffing box, in addition to four sets for piston rods; A spare hose and nozzle for each steam tube cleaner; One-eighth of a complete set of grate bars and bearers for all furnaces, and one pattern for each casting in fur- nace; One dead plate for furnaces and one pattern for same; One complete set of brasses for two of the main-engine connecting. rods; One complete set of brasses for two of the main-engine crossheads; Two per cent of each shape of boiler tubes used in the construction of the boilers and such other spare parts of boilers as may be required by the Bureau of Steam Engineering after an inspection of the drawings; Two hundred condenser tubes packed in boxes; Fifty condenser-tube glands; 53 One spare spring for each safety valve, one for each sentinel valve, and one for each cylinder and pump relief valve; One spare basket for each Macomb bilge strainer; One set of coils or tubes for each evaporator, with steam head. Wherever duplicate pieces are furnished for one ot two or more pieces of machinery of the same size, they must be made strictly interchangeable. All finished duplicate pieces not of brass will be painted with three coats of white lead and oil and well lashed in tarred canvas, with the name painted on outside unless otherwise directed. Brass pieces will be marked or stamped. All pieces will be stowed in an approved man- ner. All boiler tubes will be securely stowed in racks, or as directed. These duplicate pieces are not to be regarded as part of the machinery weights, but are to be delivered at such navy yard as may be directed. 140. MATERIALS AND WOEKMANSHIP. All castings must be sound and true to form, and before being painted must be well cleaned of sand and scale, and all fins and roughness removed. No imperfect casting or unsound forging will be used if the defects affect the strength or to a marked degree its sightliness. All nuts on rough castings will fit facings raised above the surface, except where otherwise directed. All flanges of castings will be faced, and those coupled together will have their edges made fair with each other. The faces of all circular flanges will be made male and female when under pressure g-reater than 200 pounds to the square inch and grooved in all other places. When required all bolt holes in permanently fixed parts will be reamed or drilled fair and true in place, and the bodies of bolts finished to fit them snugly. All brasses will be properly channeled for the distri- bution of oil. 54 Packing for stuffing boxes will be such as may be approved. AH material used in the construction of the machinery will be of the best quality. The iron castings will be made of the best pig iron — not scrap — except where other- wise directed. Composition castings will be made of new materials. The various compositions will be by weight, as follows: For all journal boxes and guide gibs where not other- wise specified: Copper 6, tin i, and zinc ^ parts. Naval brass: Copper 62, tin i, and zinc 37 per cent. For composition not otherwise specified: Copper 88, tin 10, and zinc 2 per cent. Manganese bronze and Muntz metal will be of the best commercial quality. Antifriction metal will be of approved kind. Ornamental brass fittings will be of good uniform color. All castings will be increased in thickness around core holes. Core holes will be tapped and core plugs screwed in and locked, except where bolted covers are used, or where it may be directed that the holes be left open. All steel forgings will be without welds and free froni laminations. All flanges, collars, and offsets will have well rounded fillets. All boiler plates, stays, and tubes will be well cleaned of mill scale by pickling or other approved means. All flanged parts of boilers will be annealed, after flanging, in an approved manner. India-rubber valves will be of approved kind, of best commercial quality. All bolts for securing the boiler attachments will, where practicable, be screwed through the boiler plates, with heads inside. All work will be in every respect of the first quality and executed in a workmanlike and substantial manner. Any portion of the work, whether partially or entirely completed, found defective, must be removed and satis- factorily replaced without extra charge. 55 141. TESTS OF MATERIAL. All steel used in the construction of the boilers, and all steel forgings and castings, will be tested in accord- ance with rules to be prescribed by the Navy Depart- ment. All boiler tubes will be tested to 1500, and condenser tubes to 300 pounds pressure per square inch, applied internally before being put in place. If India rubber valves are used, they will be taken at random, and must stand a dry -heat test of 270° Fahren- heit for one hour, and a moist-heat test of 400° Fahren- heit for three hours, without injury. 142. TESTS OF BOILERS AND MACHINERY. Before the boilers are painted or placed in the vessel they will be tested under a pressure of 360 pounds to the square inch above atmospheric pressure. This pressure will be obtained by the application of heat to fresh water within the boilers, the water filling the boilers quite full. The boilers, steam pipes, and valves and all fittings and connections subjected to the boiler pressure will be tested to 360 pounds to the square inch. After the boilers are placed in the vessel and connec- tions are made, the boilers and pipe connections will be tested by steam to 300 pounds per square inch, and all leaks made tight before they are clothed. The high-pressure cylinders and valve chests will be tested by water pressure to 360 pounds to the square inch, the intermediate-pressure cylinders and connec- tions to 180 pounds, and the low-pressure to 90 pounds. The exhaust side of the low-pressure valve chests will be tested to 30 pounds. The condensers will be tested to 30 pounds. The pumps, valve boxes, air vessels, and pipes of all feed pumps will be tested to 500 pounds per square inch. The cylinders and condensers will be tested before being placed on board, and must be so placed that all parts may be accessible for examination by the inspector during the tests. All parts will also be tested after 56 l>eing secured on board. No lagging or covering is to be on the cylinders or condensers during the tests. All pressures to be above atmospheric pressure. The circulating pumps will be tested by discharging water under conditions as nearly as possible like those they will be working under when throwing water from the bilges. They must discharge the water at the same height as the water line is above the pumps and through the same length and size of pipe, drawing water from the same depth as the lowest part of the bilge-suction pipe below the pump and through the same length and size of pipe. Each pump must throw 750 gallons per minute under this head. When the engines are completed they will be firmly bolted on a good foundation in the shop " A good dyna- mometer of approved design will be applied to each engine in turn. There will then be made a progressive test of each engine up to 412 revolutions at full steam pressure, beginning with low pressures of steam, and various rates of revolution for each pressure, the engine being indicated for each speed, and the dynamometer being read at the same time. Before this test is made the Bureau of Steam Engin- eering will issue explicit instructions to be followed. 143. PAmTING. After a satisfactory test the boilers will be painted on the outside v^ith two coats of brown zinc and oil, and when in place the fronts will be painted with one coat of black paint. All engine work, not finished, will be primed with two coats of brown zinc and oil, and when placed in position on board the vessel will be painted with two coats of paint of approved color. The shafting, when in place, will be painted with two coats of red lead and oil and two coats of black paint. The smoke pipes will be thoroughly painted before and after erection on board. Special care will be taken that the^ outside of the smoke pipe and the inside of the casing are thoroughly painted before the smoke pipe and 57 casing are secured together. The ventilators will be painted similarly to the smoke pipes. All pipes will be painted in accordance with a schedule to be hereafter furnished. 144. PRELIMINARY TESTS AND TRIALS. The boilers will be used for the shop test of the engines elsewhere specified. After boilers are placed on board and connections made, steam will not be raised to a higher pressure than 50 pounds until the specified water test has been made. All expense of preliminary tests will be borne by the contractor. 145. SUPERINTENDING ENGINEER'S OFFICE. • A suitable office and a suitable drafting room, properly furnished and heated, will be furnished by the contractor for the use of the Superintending Naval Engineer and his assistants. 146. RECORD OF WEIGHTS. All finished machinery, boilers, and appurtenances thereof, as fitted, and all spare machinery and tools herein specified, will be weighed by the contractor in the pres- ence of the Superintending Naval Engineer, or one of his assistants, before being placed on board ; and no part of the material will be placed on board without being so weighed to the satisfaction of the Superintending Naval Engineer. 147. WORKING DRAWINGS. All drawings necessary for the prosecution of the work must be prepared by and at the expense of the contractor. Those which are developments of the drawings fur- nished and of these specifications will be subject to the approval of the Bureau of Steam Engineering before the material is ordered or the work commenced; and a copy of each working drawing, after approval by the Bureau of Steam Engineering, will be furnished to the Superin- tending Naval Engineer before the work shown by the drawing is commenced. A copy of each drawing accom- panying orders for steel castings or forgings will also be supplied when the work is ordered. 58 The drawings will be made to scale, with figured dimensions of all parts. If a correction or change is made in any part of a finished drawing, the dimension will be written with the word " marked " after it. Mate- rials will be hatched in accordance with the Bureau standard, or be plainly marked with lettering. In the drawings furnished, figured dimensions, where given, will be followed, and not scale dimensions, unless otherwise directed. All discrepancies discovered in drawings, in specifications, or between drawings and specifications, will be referred to the Bureau of Steam Engineering. 148. DRAWINGS OF COMPLETED MACHINERY. The contractor will make and furnish to the Bureau of Steam Engineering, through the Superintending Naval Engineer, one complete set of drawings, and three sets of blue prints on cloth of approved quality, of the boilers, machinery, and appurtenances as actually completed, including plans of the same as fitted on board the vessel. These drawings will include every piece of machinery, both in whole and in part, and will be in such detail as would enable the entire machinery to be duplicated without additional drawings. No sheet will contain drawings of more than one part of the machinery, except those intimately connected with each other. The detail drawing of each part of the machinery will be furnished within one month after the completion of the part with- out waiting for its incorporation into the machine as a whole. Detail drawings will be made to a scale of not less than ij^ inches to the foot. General plans of the machinery in place in the vessel will be made to a scale of % inch to the foot. The pipe plans will be made to a scale of not less than % of an inch to the foot. The pipe plans will be divided into at least two parts — one showing steam and exhaust pipes, and the other showing all other pipes. The pipe plans will be colored in accordance with a schedule to be furnished, to indicate the purpose which the pipes are intended to serve, and accompanied by an explanatory index. 5864 9 59 All drawings will be made on the best quality of tra- cing cloth ; all sheets being of " double elephant " size, or multiple of this. Detail drawings will be hatched, where in section, in accordance wnth a schedule to be furnished, to show the various metals employed. 149. CHANGES IN PLANS AND SPECIFICATIONS. The contractor will make no changes in the plans or specifications without the approval of the Navy Depart- ment. In case it is thought advisable to make changes, the contractor will make application by letter to the Bureau of Steam Engineering, through the Superintend- ing Naval Engineer, stating the nature of the change, accompanied by complete plans and specifications of the proposed change, together with a statement of his esti- mate of the amount of increase or decrease in cost. 150. INSPECTION. The work of construction of the boilers, machinery, and appurtenances shall be at all times open to inspection by officers appointed for such purpose by the Navy Department. Every facility will be afforded such inspec- tors for the prosecution of their work. All handling of material necessary for purposes of inspection will be done at the expense of the contractor. All test specimens necessary for the determination of the strength of mate- rial used will be prepared and tested at the expense of the contractor. The contractor will furnish the Superin- tending Naval Engineer with a weekly list of the num- ber of men of each class employed upon the work, together with a statement of the number of hours' labor in each class. 151. OMISSIONS. Any part of the machinery or any article pertaining thereto which may have been inadvertently omitted from these specifications or from the official drawings, but which is necessar}^ for the proper completion of the vessel, is to be supplied by the contractor without extra charge. o i i