The UnitIed States Deedg-ihg 
 
 AND COH^TEIJCTIOH COMPANY 
 
Digitized by the Internet Archive 
 in 2019 with funding from 
 
 University of Illinois Urbana-Champaign Alternates 
 
 https://archive.org/details/unitedstatesdredOOunse 
 
INDEX TO CONTENTS. 
 
 Pages 5 to 12 —Financial Scheme. 
 
 Purchase price of Patents. 
 Capital of Company. 
 
 Issne of Shares. 
 
 Bonus,- 
 
 Page 9 -Patents to be purchased. 
 
 “ 11 —Form OE Subscription. 
 
 Page 
 
 (( 
 
 U 
 
 Pages 
 
 Pages 
 
 Page 
 
 Pages 
 
 J3_Evolution of the Fruhling system. 
 
 11 .... The German Government and the Fruhling System op Dredging, 
 
 11 _Advantages of the Fruhling System of Dredging. 
 
 15-16 _ Dredging in the United States op America. 
 
 The Panama Canal. 
 
 The Erie Canal. 
 
 The Mississippi River Commission. 
 
 New York Harbor and the Ambrose Channel. 
 
 18-20 - Prices Paid for Dredging Work. 
 
 18 ... .Various large dredging works in America. 
 
 20-22 .... Policy of the Company. 
 
 Page 25 ... .Certificate Relating to the Merits op the Fruhling System op 
 
 Dredging by Herr Scholer (Chief Engineer to the German Gov¬ 
 ernment River and Harbors Department, Member Imperial Canal 
 Commission of Kiel, Germany, &c). 
 
 Pages 27-32 ....Report on the Fruhling system of Dredging, by Messrs. Flannery 
 
 Baggallay & Johnson, of London, England. 
 
 “ 33-40 _Report on the Fruhling system of Dredging, by Herr Scholer. 
 
9 
 
 UNITED STATES PATENT RIGHTS TO BE PURCHASED BY THE COMPANY. 
 
 No, 708,541 of 1902. Improved method of emptying dredging boats. 
 No. 776,049 of 1904. Improved dredging apparatus. 
 
 No. 776,050 of 1904, Improved dredging apparatus. 
 
 No. 776,051 of 1904. Improved dredging apparatus. 
 
 By the purchase of the patented inventions described, the United States Dredg¬ 
 ing AND Construction Company would also acquire the sole and entire right to purchase 
 all or any alterations or improvements that are being or may be made by the inventor 
 at any time thereon, and in addition the sole and entire right to take out in the United 
 States Patent Bights for such improvements and alterations in all or any of the 
 patents hereinbefore described, all Patent Bights so taken out becoming the absolute 
 property of the Company, in addition to the Patent Bights more particularly men¬ 
 tioned hereinbefore. 
 
13 
 
 LACK OF IMPROVEMENT IN DREDGING APPARATUS. 
 
 Mechanical genius has not applied itself to the improvement of dredging apparatus, 
 but has turned to more popular branches of engineering. Consequently dredging has 
 been carried on with machines of the same type as were in use fifty years ago, on a 
 scale which was then unthought of. These machines raise all the various materials 
 in which dredging operations are conducted, and fifty years ago were capable of 
 dredging ports and harbors quickly enough to cope with the amount of work necessary. 
 
 INCREASED SIZE OP VESSELS AND URGENT NEED OF DREDGING. 
 
 Within a few years, however, both cargo and passenger vessels have increased in 
 size and draft to such an extent that few ports and harbors can accommodate the largest 
 of them. Inability to accommodate these vessels means commercial extinction, and 
 consequently ports all over the world are faced with dredging problems of great magnitude. 
 Where a few years ago the removal of a few thousand cubic yards was all that was 
 necessary, millions of cubic yards must now be dealt with. No port had time to accom¬ 
 plish a gradual increase of its accommodation facilities, and the immediate need of 
 machines capable of removing materials with a speed which no adaptation of existing 
 types could accomplish became apparent. 
 
 EVOLUTION OP THE PRUHLING SYSTEM. 
 
 The Suez Canal and Bazine’s Suction Dredger—Sand. 
 
 When the Suez Canal was commenced it was soon found that machines then 
 known could not deal efficiently with the vast quantities of sand of which the major 
 portion of the work consisted. The difficulty was overcome by Monsieur Bazine with 
 the Suction Dredger. This invention proved entirely successful in dealing with the 
 material in which it was designed to work. At that time the chief dredging problem 
 was the removal of sand-bars, and it was thought that with the suction dredger to deal 
 with sand and the bucket dredger and grab or clam-shell dredger to deal with mud and 
 clay and other heavier substances, dredging machinery was ready to deal with every 
 description of work. Bazine, however, attempted to dredge mud with his machine 
 and failed completely. Mud being then not a very great factor in dredging, slight 
 importance was attached to the suction dredger’s failure when such work was attempted. 
 
 When, however, the extent of dredging operations necessary was so suddenly 
 increased, new problems faced the engineers. The suction dredger was again put to 
 work in mud, and again failed. The reason for the failure is: Sand is a very heavy 
 substance, which, when sucked up by the suction pipe of the dredger and emptied into 
 barges or the dredger’s owm hold, falls very qnickly to the bottom of the barge or hold, 
 and, moreover, does not require the admixture of a very large percentage of water to be 
 sucked up with it. Mud, on the other hand, requires to be mixed with a large percentage 
 of water before the suction will draw it up the pipe, and, when emptied into the 
 barge or hold, remains in suspension and does.not sink to the bottom. The percentage 
 of solids to water varies to a very great degree, but, it will be seen that, if yO per cent, of 
 water has to be drawn up with 10 per cent, of mud, only 10 per cent, of the power of the 
 vessel is being effective in actual dredging, and the waste of power is obviously 
 enormous. 
 
14 
 
 THE KIEL CANAL AND THE FRUHLINC SYSTEM OF DREDGING BY 
 
 SUCTION.—MUD. 
 
 The urgent need of a machine to dredge the sand in the Suez Canal introduced 
 Bazine and his suction dredger. The problem of dredging the mud and maintaining 
 the entrances to the Kiel Canal gave rise to the invention of the Fruhling System of 
 Dredging by Herr Otto Fruhling, of Brunswick in Germany. This invention enabled 
 the suction system to be applied to the dredging of materials, which could only be 
 accomplished previously by means of the bucket and clam or grab dredgers. 
 
 The Fruhling System resulted in the dredging of the heavier materials with 
 enormous increase in speed and decrease in cost, and moreover gave to the engineers a 
 tool which could also be worked with even greater speed and economy in sand. In one 
 dredger therefore is combined an implement which is a very considerable improvement 
 in sand dredgers and an incalculable improvement in mud dredgers. 
 
 THE GERMAN GOVERNMENT AND THE FRUHLING SYSTEM. 
 
 The Fruhling system of dredging would not be acquired when in its experimental 
 stage by the Company. Since 1902 the German Government has expended from $500,000 
 to $750,000 on the construction of these machines, has adopted the system throughout 
 the empire, and has now under construction further machines to cost nearly twice the 
 amount already expended during the last three years. Fruhling dredges are now being 
 built for employment in nearly all the German ports of importance on the Baltic Sea. 
 
 In addition, the British Dredging Company, Ltd., has already constructed two of 
 these vessels and has further vessels under construction, and lately despatched a dredger 
 under her own steam from Holland to Shanghai. The vessel arrived at her destination 
 without having experienced the slightest mishap. This quality of seaworthiness is one 
 of the notable advantages of the type. No insurance premium above the ordinary 
 marine rate for cargo vessels was paid on the vessel for the voyage, thus demonstrating 
 the high idea of her qualities held by insurance firms. Seaworthiness is of no small 
 importance when the necessity for long and rough voyages and work in rough waters is 
 considered. 
 
 The Inventor, Herr Otto Fruhling, one of the greatest experts in dredging of the 
 present time, has been retained as consulting engineer by the Company. 
 
 ADVANTAGES OF THE FRUHLING SYSTEM OF SUCTION DREDGING OVER 
 
 OTHER SYSTEMS OF SUCTION DREDGING. 
 
 The numerous separate advantages ensuing from the use of the Fruhling system 
 OF DREDGING are explained in detail and in technical language by experts in the accom¬ 
 panying reports. Its main advantages may, however, be tabulated as follows: 
 
 It is the only means whereby the suction system of dredging may be equally 
 successfully applied to work in mud and sand. 
 
 It reduces the cost of working by 75 per cent. 
 
 It is the only system which ensures the dredging of a level bottom. 
 
 It is capable of working in a sea-way when it is impossible for other dredgers 
 to be employed. 
 
16 
 
 It can be employed in work in narrow and confined spaces such as canals, 
 docks and wharfs without fear of undermining the foundations of such 
 structures by the dredging of holes in proximity thereto. 
 
 It has been proved by years of exhaustive and complete trials undertaken 
 with characteristic thoroughness by the German Government to possess 
 all of the advantages mentioned above. Information regarding the sys¬ 
 tem may be obtained by application to the German Government Harbor 
 authorities in Germany. 
 
 VARIOUS MATERIALS MET WITH IN DREDGING. 
 
 The various grades of materials met with in dredging operations may be briefly 
 enumerated as follows; 
 
 Sand, silt or sand and mud mixed, clayey mud, gravel (sand and stones mixed 
 together); clay; “hard-pan,” a material consisting of a peculiar kind of clay mixed with 
 stones of larger size than those usually described as gravel, which hardens into a very 
 hard cement-like substance; boulders, and bed or slab-rock. 
 
 Of these materials the Fruhling System can deal with all excepting clay, hard- 
 pan, boulders, bed or slab rock, it is possible to deal with gravel, but it is not often 
 attempted on account of its being apt to “score” or wear out the inner casing of the 
 suction pipes. 
 
 SOME INSTANCES OF DREDGING AND EXCAVATION WORK IN THE UNITED 
 
 STATES. 
 
 THE PANAMA CANAL. 
 
 Though the need for dredging the actual canal has not yet arrived, important 
 maintenance dredging work must be at once proceeded with at the ports of Colon 
 and Panama so that ocean-going vessels bringing supplies for the canal work may 
 enter and leave in safety. The material met with in dredging work in these localities 
 is MUD, and therefore peculiarly suitable to the Fruhling system. 
 
 As water is admitted to the completed portions of the Canal the amount of 
 dredging work will of course increase, and as the Fruhling system is especially adapted 
 to work in narrow spaces, dredges a perfectly level bottom, and deals with such a wide 
 range of materials, it should be very largely employed in the dredging of the Canal. 
 The great reduction of the expense of dredging work attained by use of the Fruhling 
 system must also be an argument greatly in its favor. 
 
 The authorities who will superintend the construction, excavation and up-keep of 
 the Canal must employ the best tools to accomplish the end in view, and it has been 
 proved beyond any possibility of doubt by the German Government engineers, who are 
 famous perhaps above all others for thoroughness and conservatism, that the Fruhling 
 system is the best dredging tool extant for work in sand and mud. 
 
 Of the $200,000,000, or whatever the eventual sum may be, which is expended on 
 the Panama Canal works, a very large portion must be expended in dredging work in 
 material in which the Fruhling system has won its chief successes. 
 
16 
 
 THE ERIE CANAL. 
 
 The Erie Canal also presents a great opportunity for the Company. 
 
 Between $5,000,000 and $6,000,000 have already been expended on the work, 
 $10,000,000 having been set aside by the State as a first appropriation. During the next 
 two or three months the balance of $4,000,000 of this sum will have to be paid out for 
 work done, and a further sum set aside for new contracts. 
 
 The engineers’ estimate of the total cost of the enterprise is $100,000,000, and 
 there is little doubt but that the whole of this amount will be expended. 
 
 The work offers good opportunities for the employment of the Frtjhling System. 
 
 THE MISSISSIPPI RIVER COMMISSION. 
 
 This Commission was appointed many years ago by the United States Govern¬ 
 ment, and has since been in almost continual session for the study of the problem 
 presented by the Mississippi River in the obstructions continually arising throughout its 
 navigable course. 
 
 Enormous amounts of money are annually spent in the attempts to keep the 
 necessary channels open. The rapidity with which the sand and other materials accumu¬ 
 late renders the work of the Commission extremely onerous. The fact that it is sand 
 and silt which causes so much trouble in this instance immediately suggests the use of 
 the Pruhling System as a means whereby these accumulations can be dealt with. The 
 matter will be investigated. 
 
 THE AMBROSE CHANNEL CONTRACT IN NEW YORK HARBOUR. 
 
 The contract for the dredging of the East or Ambrose channel in New York 
 Harbour called for the removal of no less than 45,000,000 cubic yards of material, or some 
 60,000,000 tons—a work of international importance. The present channel is danger¬ 
 ously narrow and shallow, and provides absolutely inadequate accommodation for the 
 traffic using it. 
 
 ARTICLE FROM “ THE SCIENTIFIC AMERICAN ” ON THE FRUHLING SYSTEM. 
 COMMENTS ON THE APPLICABILITY OF THE FRUHLING 
 SYSTEM TO THE WORK IN NEW YORK HARBOUR. 
 
 Showing the enormous extent of this contract, it may be mentioned that the 
 total amount of material to be removed for the completion of the channel exceeds by 
 SIX TIMES THE TOTAL AMOUNT ANNUALLY DREDGED FROM THE GREAT ENGLISH PORTS OF 
 
 Manchester, Hull, Liverpool, the Clyde, and London. 
 
 One of the Fruhling dredges built for the German Government within the last 
 year is the largest dredger in the world. 
 
 The following extract from the Scientific American is here quoted and comment 
 made, showing what would hqve been the result of applying such a vessel to the New 
 York contract. 
 
17 
 
 Extract from the “Scientific American” for September 2nd, 1905. 
 
 ■ A GIANT DREDGE (THE FRUHLING DREDGER). 
 
 “ The gigantic dredger represented in the accompanying photograph has recently 
 been completed by F. Schichau, of Elbing and Danzig, Germany, for the Imperial Navy, 
 and it is intended for maintaining the channel of the Jade River at a convenient depth. 
 
 The dredges available in the Prussian seaports, up to this time, had proved unable 
 to deal with the Jade Channel, which is rather shallow for the new, large draft German 
 liners. 
 
 This dredge, which is the biggest in the world, sailed for Wilhelmshaven after a 
 short test of its engines made in the Danzig shipyards, and in the latter part of December 
 rapidly accomplished its trial dredging with splendid results. 
 
 Whereas, the contracts called for an hourly output of Jf.,680 cubic yards in soft 
 ground, the dredge by far exceeded this figure, readily dealing with 6,500 cubic 
 YARDS (or about 7,700 tons) per hour, instead of 4^,080, as stipulated.^’ 
 
 (Note.— The dredgers Mills and Thomas, the contractors’ dredgers on the 
 Ambrose Channel contract in New York Harbor, which are only slightly 
 smaller than the dredge now described, together dredged an average amount 
 PER DAY OF ONLY 11,000 cubic yards during the year 1904 in easy sand, or 
 ONLY ABOUT ONE-HALF AS MUCH AGAIN AS THE FrUHLING DrEDGER RAISED IN 
 ONE HOUR BY ITSELF.) 
 
 “In heavy sandy ground, of specific weight 1.96, the dredge excavated 4,680 cubic 
 yards per hour, 65 per cent, of solid ground being raised by the pressure pipes.” 
 
 (Note.— The percentage of solids raised with the ordinary suction system 
 RARELY exceeds 10 per cent.) 
 
 “ As regards the speed stipulated by contract, this had to be 8 knots with full loads 
 and tanks pumped full. The mean speed during a run of several hours’ duration was, 
 however, 10 knots instead of 8 knots, showing an enormous increase in the performance 
 of the dredge. The coal consumption was extremely favorable, being 0.85 pounds per 
 horse power per hour. 
 
 Owing to this increase in output and speed the dredge is able to raise and re¬ 
 move AS much as 31,200 cubic yards of soil in one day, corresponding to a yearly 
 OUTPUT OF 7,800,000 CUBIC YARDS IN 250 WORKING DAYS.” 
 
 [Note.— The latest Government figures, issued in October, 1905, show that 
 the Mills and Thomas (referred to above) together with the two Government 
 DREDGERS, the Manhattan and the Atlantic, which are of nearly the same size 
 as the two contractors’ dredgers, dredge and remove some 650,000 cubic yards 
 per month, working night and day. These figures show that these four 
 DREDGERS WOULD IN A FULL YEAR OF 365 DAYS OF 24 HOURS EACH, ONLY JUST 
 EQUAL THE WORK OF THE ONE FrUHLING DrEDGE IN 250 DAYS, i. 6 ., 7,800,000.] 
 (And, in addition, it must be remembered that these four dredgers cost 
 $1,700,000 to build, whereas the FrUHLING dredger DESCRIBED COST ONLY SOME 
 $350,000.) 
 
18 
 
 “Each cubic yard of soil raised costs accordingly less than 0.6 of a cent, 
 
 INCLUDING ALLOWANCE FOR THE DEPRECIATION OF THE DREDGE.” 
 
 (Note. —The average cost of dredging and removing soil on the New York 
 Harbor contract to the Government and the contractors is about 5.50 cents per 
 cubic yard.) 
 
 “ This result is quite unique and much more satisfactory than any of the figures 
 so far realized, as the harbor dredges so far known raised each cubic yard of soil at 
 an average cost of 9.6 cents. The Schichau shipyards, we are informed, have secured 
 contracts for a number of these novel dredges, especially for foreign ports.’^ 
 
 (Note. —Simple calculations show that had the Government constructed one 
 Fruhling dredger, such as is described, and placed it on the New York contract, 
 
 it would have saved: 
 
 In initial cost of construction. $1,350,000 
 
 In working expenses on the total amount of material 
 
 to be removed no less than. $2,500,000 
 
 And would have been able to complete the work in less time. 
 
 PRICES PAID IN CONTRACT FOR DREDGING WORK. 
 
 « 
 
 Prices paid for dredging work vary considerably. For work in light materials 
 such as sand or silt from 10 cents to 30 cents per cubic yard may be obtained and in 
 cases of pressing urgency as much as 50 cents or even $1 per cubic yard has been paid. 
 The amount to be dredged and the conditions under which dredging has to be carried 
 out influence the price. For instance in the great work for dredging the channel in 
 New York Harbour only 9 cents per cubic yard was paid. For work in the heavier 
 materials it is even harder to give any set table of prices. It is only safe to say that 
 from 30 cents up to almost any amount is paid. As much as $3 per cubic yard was paid 
 in New York for the dredging of some 4,000 cubic yards of mud. The profits made out 
 of this work must have been enormous, as even at 50 cents a profit of nearly 30 cents 
 per cubic yard would have been realized—if not more than that. But in such small con¬ 
 tracts the price has necessarily to be high to induce contractors to undertake the work. 
 
 The following table, compiled from the Annual Report of the Chief of Engineers 
 of the United States Army, which gives the cost and object of some of the most impor¬ 
 tant dredging works in America, serves very strikingly to show the great sums of money 
 expended on a branch of the countr 3 '’s domestic affairs to which so little of its citizens’ 
 attention is given; and, in addition, affords further proof of the unrivalled opportunities 
 and the vast field awaiting this Company. 
 
 Boston (Mass.). For a channel 1,000' wide by 27' deep; project adopted 
 
 in 1892. $1,488,751 
 
 For a channel 1,200' wide by 30' deep; adopted in 1899. 455,000 
 
 For a channel 1,200' wide by 35' deep; adopted in 1902. 7,994,248 
 
 New Haven (Conn.). For a channel 400' wide by 20' deep; 4 miles 
 
 long (3,287,000 cu. yds.). 345,000 
 
 Baltimore (Md.). For maintenance of a channel 30' deep; adopted in 
 
 1896 (annual payment of). 60,000 
 
19 
 
 Charleston (S. C.). For a channel 600' wide by 26' deep; adopted in 
 
 1899 (between). $4,000,000 and 
 
 5,000,000 
 
 Chesapeake Bay. For a channel 100' wide by 10' deep; adopted in 
 
 1899. 274,310 
 
 Great Lakes. For a channel between Chicago, Duluth and Buffalo, 
 
 300' wide by 20' deep; adopted in 1892. ... 3,340,000 
 
 Reclamation work. Southern Idaho. Snake River Valley, and a canal 
 
 69 miles long with 80' width at bottom, adopted 1903. 6,000,000 
 
 Cleveland (Ohio). For a channel to be dredged to a depth of 25'; 
 
 adopted in 1899. 478,400 
 
 Galveston (Tex.). A ship channel 100' wide by 25' deep, and a channel 
 
 in the harbor 600' wide and 25' deep; adopted in 1903. 4,000,000 
 
 And an annual payment for maintenance work of. 100,000 
 
 Portland Harbour (Me.). Dredging to a depth of 30'; adopted in 1896 946,250 
 
 San Diego Harbour (Cal.). For a channel 500' wide and 24' deep; 
 
 adopted in 1900. 542,850 
 
 Mississippi River Commission. For a channel 1,000' wide and 35' 
 
 deep; adopted in 1900. 6,000,000 
 
 Construction of tugs for upkeep, &c.; an annual payment of.. 150,000 
 
 Mississippi. Maintenance work in South Pass Channel; adopted in 
 
 1889; an annual payment of. 100,000 
 
 (This being only an infinitesimal portion of the amount annually 
 expended.) 
 
 Tampa Bay (Fla.). For a channel 500' wide by 27' deep; adopted in 
 
 1899 . 750,000 
 
 Diverting of Yazoo River and Vicksburg Harbour (Miss.). Improve¬ 
 ment, excavation of 5,836,366 cu. yds. earth. 1,200,000 
 
 Norfolk (Va.). For a channel 450' wide and 28' deep; adopted 1899. 359,516 
 
 WiMPAH Bay (S. C.). For construction of ietties and dredging; adopted 
 
 1902. 1,848,000 
 
 Mobile Harbor (Ala.). A channel 100' wide by 23' deep; adopted in 
 
 1902 . 1,640,000 
 
 And a channel 300' wide and 30' deep. 91,250 
 
 Pawtucket River (R. L). For a channel 100' wide and 12' deep; 
 
 originally adopted in 1883 and further revised 1904. 382,500 
 
 Passaic River (N. J.). For a channel 200' wide by 10' deep; adopted 
 
 1892. 547,697 
 
 Albemarle Sound (N. C.). For a channel 80' wide by 9' deep; adopted 
 
 in 1890. 306,667 
 
 Pensacola (Fla.). For a channel 500' wide by 30' deep; adopted in 1902. 220,000 
 
 (part dredge construction.) 
 
 Philadelphia (Penn.). For a channel 600' feet wide by 30' deep; 
 
 adopted in 1899. 6,810,000 
 
 St. John’s River (Fla.). Dredge construction and for dredging; adopted 
 
 in 1902. 1,450,000 
 
20 
 
 Savannah Harbour (Ga.). For Harbour Improvement; adopted in 
 
 1896. $992,250 
 
 Keweewan Bay to Lake Superior (Mich.). For caual construction, 
 
 width 70', depth 16'; adopted in 1^96. 1,115,000 
 
 Detroit River (Mich.). For a channel 600' wide and 20' deep between 
 
 Detroit and Lake Erie; adopted in 1892. 1,554,000 
 
 Revised and additional scheme adopted in 1902 for a channel 
 
 600' wide by 21' deep. 2,200,000 
 
 Irrigation lake and canals at Roosevelt (Arizona), adopted 1901. 31,500,000 
 
 CONSTRUCTION OF DREDGERS AND WORK FOR THE COMPANY. 
 
 A number of contracts for dredging work have already been offered on which the 
 Fruhling system could be profitably employed, and contractors have everywhere evinced 
 great interest in the system and have recognized its merits. It h:3s not been deemed 
 advisable, however, to make any decision as to what work the Company would under¬ 
 take when formed, for the reason that the most minute details of any such work must 
 be gone into with an amount of care and thoroughness it would be impossible to afford 
 under the present circumstances. 
 
 Investigations of the conditions under which dredging operations are carried out 
 and the positions of various contractors in relation to their progress in contracts under¬ 
 taken by them have been made, and it is certain that the Company will when formed be 
 able to obtain all tbe work it can conveniently handle. In fact it may be said that the 
 amount of work the Company will be able to secure will only be limited by the amount 
 of the Company’s resources for the building of Fruhling dredgers. 
 
 In view of the fact that it will in any case be necessary that the Company shall 
 know tbe cost of dredger construction plans and specifications, a model of a large Fruh¬ 
 ling dredger has been prepared by Mr. William A. Fairburn, the Superintending 
 Engineer to the Southern Pacific Atlantic Steamship Lines. Mr. Fairburn has the 
 highest reputation as a designer of all types of steamships, and the two largest freight¬ 
 carrying vessels in the world—tbe Minnesota and the Dakota (among many other large 
 vessels) were designed by him. Moreover, Mr. Fairburn has introduced methods into 
 steamship construction by which the cost of construction is very materially reduced 
 without any sacrifice of efficiency. Mr. Fairburn has also had considerable experience 
 in dredging matters, is thoroughly conversant with the main features of the Fruhling 
 system, and is, in addition, impressed with its merits. 
 
 Before the completion of the plans now in course of preparation by Mr. Fairburn, 
 Herr Frubling would be consulted and the plans submitted to him. Herr Fruhling 
 would prepare the specifications and plans for the construction of his dredging head and 
 apparatus in accordance with the requirements of the hull designed by Mr. Fairburn. 
 A dredger built on the plans prepared by two such experts would undoubtedly be the 
 best obtainable. 
 
 The cost of the vessel Mr. Fairburn proposes would be $275,000. The vessel would 
 be a “ self-containing ” dredge with a hopper capacity of 2,000 tons of dredged material. 
 The dredging capacity would be 5,000 cubic yards per hour in good material. In difficult 
 
 \ 
 
21 
 
 material Mr. Fairburn is of opinion some 8,000 cubic yards could be dealt with in a day 
 of ten working hours, i. e., 200,000 cubic yards per month of 25 days. 
 
 The cost of operating the difficult material alluded to per month would be $6,200 
 per month. The various items of expense being estimated as follows: 
 
 Pay roll of complement. $937 00 
 
 Coal. 1,125 00 
 
 Food. 255 00 
 
 Oil, water and stores. 175 00 
 
 Kepairs. 300 00 
 
 Superintendent. 200 00 
 
 Office expenses. 400 00 
 
 Depreciation. 1,525 00 
 
 Insurance and miscellaneous expenses. 283 00 
 
 Total cost op operating for One Month . 5,200 00 
 
 The figures for depreciation are based on the life of the boat being fifteen years— 
 which is much less than the true life of the vessel should actually be. The other items 
 in the foi'egoing table are estimated by Mr. Fairburn out of his great experience in the 
 designing construction and management of steamships. 
 
 The plans, &c., of the dredger described should be of great value to the Company. 
 It is not, of course, to be taken that the building of this dredger should be proceeded 
 with as soon as the Company is formed. It would, of course, be quite possible to build 
 a dredger on the Fruhling system for a sum much below that needed for the construc¬ 
 tion of such a vessel as is described hereinbefore. As instancing this fact the dredger 
 reported on by Messrs. Flannery, Baggallay & Johnson, of London, England (in their 
 report attached to this proposal), i. e., the Nicolaus, engaged in maintaining the entrance 
 to the Kiel Canal, cost only some $100,000 to build, and is capable of raising nearly 3,000 
 cubic yards per hour, but has hopper capacity for only some 500 tons, and is therefore 
 much smaller than the vessel Mr. Fairburn is designing. It would be possible to build 
 a Fruhling dredger without any hopper capacity capable of doing excellent work at 
 1,000 to 1,500 cubic yards per hour, at a cost of $75,000. The Company’s first 
 dredger will be constructed to meet the requirements of work undertaken, and will be 
 dominated by the amount of funds at the Company’s disposal. Such a vessel as is 
 described would, however, be capable of undertaking work of the class it is desired to 
 obtain, that is to say, of work of importance and magnitude. In such work the vessel 
 would earn large profits. 
 
 It is necessary, however, that it Should be well understood that it is not claimed 
 for the Fruhling System that it is capable of undertaking dredging work in all sorts 
 of materials. As has been previously pointed out herein there are various kinds of 
 materials such as heavy clay and rocks which it is impossible to deal with under any 
 circumstances by means of the suction system. To deal with these materials dredgers 
 of the clam-shell, bucket or dipper type must be employed. In considering tbe suit¬ 
 ability of contracts therefore it will be necessary to make the most careful investigations 
 with a view to ascertaining as nearly as is possible the exact proportions of the materials 
 
 / 
 
22 
 
 with which the Fruhling system can or cannot deal. Naturally those contracts offering 
 the largest proportions of work in mud and sand will be first considered. It may very 
 possibly happen that a contract will show 85% of mud and sand and 15% of rocks and 
 heavy clay. In such cases it is the custom of the Government to offer the contract 
 usually in two portions, i. e., the hard and the soft work, at two different prices. If it 
 is considered advisable to make an offer for the whole of the work in both soft and hard 
 materials the Company will either hire or build dredgers for the work on the hard 
 materials. In cases where the whole work must be tendered for, very careful figuring 
 is necessary, and the advice of the best expert obtainable of the greatest importance. 
 In these cases Herr Fruhling will be of inestimable value to the Company with his great 
 dredging knowledge and experience. 
 
 The intentions of the proposed Company with regard to construction of plant 
 have only been touched upon herein in the most general terms, for the reason that the 
 policy of the Company will be in the hands of its Stockholders who will from the outset 
 have perfect freedom in deciding the work that will be taken up and the work that will 
 be avoided. 
 
 The machines it is proposed to purchase may be divided into two classes— Main 
 and Auxiliary. The main devices are Thk Fruhling Patent Suction Pipe Dredging 
 Head Attachment. The auxiliary machines consist of various adaptations of the main 
 device for work under extraordinary conditions As instances, it may be said that Herr 
 Fruhling has invented means for reversing the dredging head and dredging in a diagonal 
 instead of a longitudinal manner. Herr Fruhling has also invented a system of piping 
 for the scouring out of the holds of dredging vessels. This system has been fitted to 
 each of the dredgers built for the German Government, with very marked success. 
 
 PROSPECTS OF THE COMPANY. 
 
 THE COMPANY OWNING THE FRUHLING SYSTEM WILL BE ABLE TO 
 UNDERTAKE DREDGING WORK AT A LOWER FIGURE THAN WILL BE POS¬ 
 SIBLE TO ANY COMPETITOR AND AT THE SAME TIME TO EARN LARGER 
 PROFITS. 
 
 COPIES OF REPORTS, &c. 
 
 Certified copies of the report by Messrs. Flannery, Baggallay and Johnson and of 
 the certificate by Herr Scholer on the Fruhling System may be seen at No. 15 William 
 Street, New York (City), the office of Mr. W. Donald Angier. The original of the 
 address on the Fruhling system given by Herr Scholer at the meeting of the Inter¬ 
 national Navigation Congress at Dusseldorf is in Germany. 
 
REPORTS. 
 
25 
 
 FRUHLINQ SYSTEM. 
 
 The following certificate shows the work done by the system on the Kiel Canal in 
 Germany, and the high opinion in which it is there held hy authorities most competent 
 to judge: 
 
 KIEL, 12th March, 1903.—This is to certify that the dredger 
 JVicolaus in the Emperor William Canal from the 15th October, 1901, to 
 the 1st March, 1903, has dredged in 700 working hours 1,350,000 tons 
 of sand, mnd and silt, and has transported and discharged this material 
 for a distance of 1.5 miles in 1,450 hours. The average cost of the above 
 work (including transport) was three-fifths of a penny per ton (about one 
 cent in U. S. A. currency). 
 
 After carefully watching the work done by the Mcolaus during the 
 above period I am able to say that, in my opinion, the Fruhling system is 
 the MOST RELIABLE, ECONOMICAL AND EFFECTIVE system of 
 maintenance dredging I have seen. 
 
 (Sig^ned) ^CUOLER. 
 
 Chief Engineer to the German Gov., Member of the 
 Imperial Canal Commission at Kiel. 
 

27 
 
 Report No. 1. 
 
 Report made by 
 
 FLANNERY, BAGGALLAY & JOHNSON, 
 
 Consulting Engineers. 
 
 Sir Fortescue Flannery, M.I.C.E., M.I.M.E, 
 Robert Baggallay, M.I.M.E. 
 
 Alexander B. Johnson, M.I.N.A. 
 
 Herbert B. Gregson, Wh.Sc., A.M.I.C.E., M.I.N.A. 
 Ernest C. Given, A.M.I.C.E., A.M.Mech.E. 
 
 FRUHLING SYSTEM. 
 Steam Dredger “Nicolaus.” 
 
 To W. Donald Angier. 
 Dear Sir: 
 
 9 Fenchurch Street, 
 
 London, 
 
 October Gth, 1902. 
 
 At your request we proceeded to Hamburg, and from there to Brunsbuttel, at tbe 
 Elbe entrance of the Kaiser William or Kiel Canal, to inspect and report on the steam 
 dredger “ Nicolaus,” fitted with dredging system by Herr 0. Fruhling, of Brunswick. 
 
 We visited vessel on the 30th September, 1902, and found that the steam dredger 
 “Nicolaus” had been constructed specially for working in and at the entrance of the 
 Kaiser Wilhelm Canal, her dimensions being about 47 metres (155 feet) long by 8^ metres 
 (28 feet) wide, these dimensions being the largest suitable for manoeuvring and turning 
 vessel round in the Canal. 
 
 On deck the machinery consists of a powerful double winch forward, fitted for the 
 purpose of working two anchors to pull vessel forward, should it be necessary to work 
 with anchors and chains instead of propellers; the anchors can also be used to aid pro¬ 
 pellers in forcing vessel forward should very stiff bottom be encountered. There are 
 also four winches—two forward and two aft—for working the hoppers when this system 
 of emptying vessel is used. Also a powerful crane aft for raising and lowering the 
 
28 
 
 dredging gear. This crane is also designed for the purpose of raising wreckage, etc., and 
 strongly ties the two halves of the stern of the vessel together. In addition there are 
 several valves, valve-rods, etc., led through the deck for manipulating the valves in the 
 piping system. 
 
 Vessel is constructed as a hopper dredger, and has three compartments for 
 holding the dredged material, one forward of 200 cubic meters (201.6 cubic yards) 
 capacity, and two aft, one on each side of the gap, of 100 cubic metres (130.8 cubic 
 yards) capacity each, or a total capacity of 400 cubic metres (523.2 cubic yards). The 
 boilers and machinery are situated amidships, and this arrangement of holds permits of 
 vessel always being kept on an even keel. 
 
 The vessel is fitted with two sets of engines of 120 h.p. each, to drive the twin 
 screws for propelling vessel, and in addition in the machinery department are: A 
 compound engine of 150 h.p., which makes about 250 revolutions per minute when 
 driving the centrifugal pump for dredging; a Blake pump 12" X IS^" X 14" X 12" for 
 delivering water under pressure to dredger head, to scour out holds if necessary, or to 
 be used for salvage operations; a dynamo, and the usual auxiliary machinery. Steam 
 is supplied by two boilers of the ordinary marine type, working at a pressure of 8 atmos¬ 
 pheres. The suction pipe has a diameter of I5f". We found the whole of the machinery 
 apparently in very good condition. 
 
 The piping system of vessel is, in our opinion, very complete, and should the 
 dredged material become too solid to be pumped out of the holds, it can be loosened 
 and softened by means of opening the valves, or, should this not prove effective, by 
 putting water urrder pressure through other pipes by means of the Blake pump. This 
 arrangement is also patented by Herr Fruhling. 
 
 The special dredging apparatus invented by Herr 0. Fruhling consists principally 
 of a strong box girder, which contains the suction pipe, and is attached to vessel and 
 held in position at the forward end of gap by two trunnions working in bearings. At 
 the after end of the box girder is the specially-designed dredger head, which is raised or 
 lowered as required through the gap in vessel by means of the crane at after end of ves¬ 
 sel. The dredger head, which in this case is about metres (11^ feet) wide, consists of 
 two principal parts. The forward or front part is in the form of a bucket or scoop, 
 having several sharp prongs or points on the edge. This, on being drawn forward, scoops 
 up the material to be dredged; and should the material dredged be solid the prongs or 
 points assist to atomize or split it up. The after or back part consists of a chamber 
 which is termed the mixing chamber, into which the material dredged by the bucket is 
 forced. It is from this mixing chamber that the dredged material is pumped. 
 
 The mixing is done by means of admitting water at the upper end of the box girder, 
 through which it flows on the outside of the suction pipe into the mixing chamber, and 
 the amount of water is controlled by means of levers from the deck. 
 
 Should the ground to be dredged be stiff soil, and require more atomizing or splitting 
 up than can be done by the bucket and mixing as above mentioned, it can be loosened 
 by the means of water under pressure, which is forced by the Blake pump through three 
 pipes laid side by side and secured on top of the box girder, and which lead through 
 smaller pipes into the prongs or points at the edge of bucket, and into the mixing 
 
29 
 
 chambers. But ia the case of the Nicolaus the material dredged off Brunsbuttel has 
 required very little mixing water. 
 
 Vessel can be discharged either by the hopper or by the dredging pump, and pipes 
 are arranged so that the dredged material can be discharged into hopper barges or on to 
 the banks of the Canal. This arrangement also enables vessel to be more useful as a 
 salvage boat, as the holds can be very rapidly filled or emptied, as desired. 
 
 In our opinion the Fruhling system has several great advantages, among which 
 are the following, viz.: 
 
 (1.) Vessel is propelled while dredging, and therefore under control the whole time. 
 This is of great importance in narrow waters or at entrance to docks, etc., especially where 
 there is much traffic; and in addition, as vessel has not to be anchored or moored, much 
 time is saved by not having to moor and unmoor. 
 
 (2.) Vessel being propelled while dredging with this system, the ground is cut or 
 scooped up level to any required depth, thus obviating the risk of forming holes in the 
 neighborhood of banks, etc., or of undermining them. 
 
 (3.) Vessel being propelled while dredging can cut or scoop up the ground for a 
 width of 11.48 feet in any required direction till holes are filled, and can after discharg¬ 
 ing same by means of landmarks, etc., return and continue the levelling process. 
 
 (4.) That by the construction of the dredging head the Fruhling system combines 
 several good points of the suction and bucket dredgers, the principal and most important 
 of which is the power of dealing by suction with soil heavier and more clay-like than 
 has hitherto been attempted successfully with a suction dredger. 
 
 (5.) That the amount of water pumped up is under the control of those working 
 the vessel, and that it is not necessary to pump up more water than is required (in the 
 case of mud) to moisten the mud for effective pumping. 
 
 (6.) That the material dredged containing only a small percentage of water, no 
 time is wasted in waiting for material to settle or extra pumping to allow water to 
 overflow from the holds, but as soon as holds are full vessel can proceed to the dumping 
 ground, 
 
 (7.) The small number of working parts, so that wear and tear and repairs are 
 reduced to a minimum. 
 
 (8.) The adaptability of the system to meet various local requirements. 
 
 We are informed by the Government Engineer in charge of the Brunsbuttell 
 district that previous to the Nicolaus commencing work, it took a large bucket dredger 
 and three steam hopper lighters working night and day to keep the channel clear, 
 whereas the Nicolaus now does the work more effectively and works only ten hours 
 per day. 
 
 From official accounts we find that Nicolaus has done the following work. 
 
 VIZ 
 
30 
 
 Date. 
 
 Time 
 
 Dredging. 
 
 Time 
 Trans¬ 
 porting 
 and Dis¬ 
 charging. 
 
 Total Time. 
 
 Quantity 
 Dredged and 
 Transported. 
 
 Total Cost of 
 Wages, Stores 
 and Upkeep. 
 
 Cost 
 
 per 
 
 Cubic 
 
 Metre. 
 
 Equiva¬ 
 lent in 
 U. S. A. 
 Currency 
 Cost per 
 Cu. Metre. 
 
 Equiva¬ 
 lent in 
 
 U. S. A. 
 Currency 
 Cost per 
 Cu. Yard. 
 
 
 
 Hrs. Mins. 
 
 Hrs. Mins. 
 
 Hrs. Mins. 
 
 Cubic Metres. 
 
 Marks. 
 
 Pfen. 
 
 Cents. 
 
 Cents. 
 
 From 
 
 Oct. 
 
 
 
 
 556,950 
 
 39,533.80 
 
 
 
 
 14th, 
 
 1901, 
 
 
 
 
 
 
 
 
 
 to 
 
 Aug. 
 
 445 59 
 
 950 57 
 
 1,396 56 
 
 
 
 7.1 
 
 .986 
 
 .750 
 
 1st, 
 
 1902. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Cubic Yards. 
 
 Dollars. 
 
 
 
 
 
 
 
 
 
 728,490.6 
 
 $9,670,68 
 
 
 
 
 In the above table the transporting from October 14th, 1901, to April 13th, 1902, 
 was for a distance of about 3 kilometres, and from April 14th, 1902, to August 1st, 1902, 
 was principally inside the Canal, and transporting was for a distance of 12 kilometres, 
 and the dredged material was discharged on land by means of the dredging pump. 
 
 At about 11.45 a.m. on 30th September, 1902, vessel unmoored in our presence 
 from the quay and commenced dredging in inner harbor, to illustrate the working. 
 Vessel then entered lock and was locked out of Canal, proceeded about 3 kilometres, 
 where the dredged material was discharged, the forward compartment of 200 cubic 
 metres being dumped through hoppers in 30 seconds, and the two after compartments 
 of 100 cubic metres each being pumped overboard in 4^ minutes. Vessel then 
 returned to outer harbour and filled all three compartments in 16 minutes with mud, 
 containing about 15 per cent, of water; then proceeded about 3 kilometres, and 
 dumped the whole cargo in 30 seconds. Vessel then returned to the harbor at 
 1.45 p.m. We requested to see the whole of the compartments filled and pumped over¬ 
 board or discharged on land. It was explained that the orifices to valves in the forward 
 compartment had been blocked up with wood plugs by order of the authorities, as they 
 were not required to be worked at present. But the Government Engineer of the dis¬ 
 trict very courteously and kindly had the plugs removed. 
 
 At 3.52 p.m. vessel was cast off from quay and at once commenced dredging in 
 inner harbor; all three compartments were filled in 12^ minutes with black mud and 
 fine sand; vessel then steamed along Canal for a distance of 12 kilometres, having to 
 ease down when passing four steamers, and arriving opposite jetty at 4.52, or in exactly 
 one hour; vpssel was then turned round in the width of the Canal, the twin screws 
 enabling this manoeuvre to be executed with facility. Vessel was moored at 5.15 p.m. 
 The shore pipe was connected by 5.29, dredging pipe was started, and all was discharged 
 by 5.40, or in 11 minutes. Vessel then returned to Brunsbuttell, where she arrived at 
 6.23 p.m. The whole operation of dredging, transporting for 12 kilometres, etc., dis¬ 
 charging and returning, occupying 2 hours 40 minutes. 
 
B1 
 
 We were permitted to attend and witness the above operations by the kindness 
 and courtesy of Herr Gilbert, Chief Engineer Inspector of the Brunsbuttel district. 
 
 The above work, including delays for docking out of Canal, transporting, etc., 
 deducting 25 per cent, for portion left in bottom of holds, increase in bulk, etc,, and 
 taking average of wages, stores, upkeep, etc., from previous table, the following table 
 gives:— 
 
 Date. 
 
 Total Time 
 Dredging, 
 Transporting, 
 &c. 
 
 Total Quantity 
 after 
 
 deducting 
 
 25 per cent. 
 
 Total Cost of 
 Wages 
 and Upkeep. 
 
 Cost per 
 Cubic 
 Metre. 
 
 Equivalent 
 in U. S. A. 
 currency per 
 Cubic Metre. 
 
 Equivalent 
 in U. S. A. 
 currency per 
 Cubic Yard. 
 
 
 Hrs. Mins. 
 
 Cubic Metres. 
 
 Marks. 
 
 Pfennig. 
 
 Cents. 
 
 Cents. 
 
 
 
 900 
 
 64.63 
 
 
 
 
 Sept. 30th, 1902 
 
 4 40 
 
 Cubic Yards. 
 
 Dollars. 
 
 7.18 
 
 1.666 
 
 1.040 
 
 
 
 1,177.2 
 
 15.79 
 
 
 
 
 The above results, especially that of the long period extending from October 14th, 
 1901, to August 1st, 1902, where on the average a cubic metre of solid material is dredged 
 for 7.1 pfennigs (.986 cent) the cubic metre, appear to us to be very good. 
 
 The Fruhling system is intended to advance and cheapen the process of dredging 
 by making it possible to apply the suction system to soils that have hitherto not been 
 available for such a system, with its consequent economy. 
 
 Until about thirty years ago dredging was accomplished by buckets upon the well- 
 known method, but after the cutting of the Suez Canal through sand by means of the 
 Bazine or suction system of dredging, it was recognized that, in the case of sandy soils, 
 a centrifugal pump, acting upon a suction pipe whose nozzle was placed close to the sub¬ 
 merged sand it was desired to dredge, would clear away such spoil more quickly and 
 more economically than the bucket system of dredging, and this centrifugal pump suction 
 system has been applied ever since with economy and advantage wherever the soil has 
 been sufficiently sandy. For clay or heavy soils, however, the suction system has never 
 yet been satisfactory, and bucket dredging has consequently continued for situations in 
 which such soils are met. Herr Fruhling’s invention has for its object the application 
 of suction dredging to soils that are less sandy and more in the nature of mud or clay 
 than has hitherto been possible for under any previously known suction system. 
 
 The system may be briefly described as a combination of mechanism in which 
 mechanical attrition is applied to heavy soil, and the same is simultaneously moistened 
 by water projected upon it, so as to reduce the soil by mixture with water to mud, or 
 an emulsion of sufficient fluidity to be acted upon by the suction of a centrifugal pump, 
 thus enabling heavy soils to be worked with the same facility as sand. The soil in the 
 neighborhood above referred to appears to have been easily dealt with in this way, and 
 
32 
 
 it would, we think, be desirable if a sample of the material in its atomized and undiluted 
 state be obtained for comparison with any soil that it is proposed to deal with under 
 this system. There appears to be no doubt that many soils, hitherto capable of being 
 worked only by the bucket or grab system, can under the Fruhling system be econom¬ 
 ically treated by suction, and therefore we regard the demonstration as most successful, 
 proving a great advance in economy and despatch in future dredging operations. 
 
 Two patents have been submitted to us, namely, 19239 of 1898 and 16797 of 1900, 
 the first being for the method of mixing the spoil with sludge, and removing it upon 
 the suction system as above described, and the second being for a skilful method of 
 mixing the sludge with water while it is deposited in the interior of the hopper for 
 the purpose of being carried away to the dumping-ground, and in such manner as to 
 keep the spoil sufficiently mixed with liquid to be pumped out of the hopper and de¬ 
 posited through the pipes on shore. In this way a vessel similar to the Nicolaus, con¬ 
 structed under the two patents above referred to, is adaptable both for winning spoil 
 from docks, harbors and such like places, when the soil is less sandy than has hitherto 
 been possible for suction, and is also adaptable to carry such spoil to a distance, and 
 deliver it through pipes to the required place for making up artificial land, as is 
 frequently required in harbor construction. 
 
 We are, Dear Sir, 
 
 Yours faithfully, 
 
 (Signed) 
 
 FLANNERY, BAGGALLAY & JOHNSON. 
 
33 
 
 Report No. 2. 
 
 IReport 
 
 ON THE 
 
 FRtfHLING SYSTEM OF DREDOmO 
 
 MADE TO 
 
 THE INTERNATIONAL NAVIGATION CONGRESS, DUSSELDORF, 1902. 
 
 BY 
 
 SCHOLER, 
 
 Kais. Regierungsrath and Member of the Imperial Canal Commission at Kiel. 
 
 The dredging operations, which are necessary to maintain the Emperor 
 William Canal, have, owing to the special conditions under which they are to 
 be carried on, necessitated the adoption of a new, specific method of dredging 
 by suction, and to make extensive trials in this respect; and as very satisfac¬ 
 tory results have been obtained during these trials, the dredger Nicolaus has 
 been constructed on the principle adopted, and thus the new method has 
 been thereby inaugurated for the first time. 
 
 The peculiar constructions in connection with the new method are the 
 invention of Regierungs-Baumeister 0. Friihling in Brunswick, and their 
 details as well as the conditions which have led to its adoption and the trials 
 made therewith are described in the present paper, because the results obtained 
 during the trials seem to point to the possibility that dredgers of similar con¬ 
 struction may be adopted elsewhere, too, with advantage. 
 
 The chief duties which the new dredger constructed for the Emperor 
 William Canal will have to perform, and which were specially kept in view in 
 working out all its details, were to keep open the entrance of the canal into 
 the River Elbe, for which purpose it will have to clear away large quantities 
 of mud, which the river is continually depositing in that locality; and also to 
 carry out small, odd jobs of dredging in the canal itself, and in addition thereto 
 to widen the bed of the canal at passing places and lay-by berths. 
 
 Besides these chief duties, the new dredger was also to serve as a break¬ 
 down floating derrick in case of accidents, to remove wrecks and to clear away 
 with expedition any accumulation of sand caused by such break-downs or 
 wrecks in the canal. 
 
 Ordinary bucket dredgers would not have been suitable for this purpose, 
 especially for performing the main duty, because their anchor chains and 
 attendant scows would have most inconveniently blocked the entrance; besides 
 which, they would not have possessed sufficient mobility to make way quickly 
 for the crowded traffic continually passing through the entrance. Moreover, 
 they would have had to be made of such large dimensions, to be able to fully 
 
 Inventor. 
 
 Use of 
 dredger for 
 maintenance 
 and excavation 
 work. 
 
 Use of 
 dredger for 
 salvage work. 
 
 Advantage 
 over ordinary 
 bucket 
 dredger. 
 
34 
 
 Advantage for 
 ordinary suc¬ 
 tion dredger. 
 
 Reduction of 
 water lifted 
 with dredged 
 material, &c. 
 
 Description of 
 Invention. 
 
 cope with the work, that the cross-section of the canal would have been unable 
 to accommodate them. 
 
 Suction dredgers of the ordinary construction would have been equally 
 unsuitable for the chosen purpose, because the material to be lifted mainly 
 consisted of soft mud or silt, which could not have been worked with such 
 dredgers, because it could not have been separated with sufficient rapidity from 
 the excessively large volumes of water which have to be dealt with in this 
 particular instance. 
 
 On the other band, there were several good points to recommend the 
 new dredger invented by Eegierungs-Baumeister Friihling, who had carried 
 out with it experiments on several occasions, and also small odd jobs near 
 Rendsburg in the vicinity of the canal, with remarkably good results. 
 
 This invention is an improvement on the ordinary suction dredger, and 
 its advantages mainly consist in the feature, that the volume of water lifted 
 with the dredged material can be regulated at will, and limited to the mini¬ 
 mum quantity, which renders dredgers of this description specially suitable 
 for removing soft mud. Moreover, it is possible to work with these dredgers 
 to a uniformly level bottom, and the formation of holes and deep pools usually 
 left by ordinary suction dredgers is thereby avoided; for this reason ordinary 
 suction dredgers cannot be used in canals where the finished excavation is not 
 to exceed a certain fixed maximum cross-section. 
 
 The special apparatus by which the advantages mentioned above are 
 attained consists of a dredging end-piece or head of special construction which 
 is fixed to the end of the suction tube, and is formed by two principal parts. 
 
 One of these, the foremost portion, is of the shape of dredging bucket 
 which excavates the ground mechanically, leaving a level flat bottom. 
 
 The othei’, hindmost portion forms a chamber or receiver, closed all 
 round, into which the excavated material is pushed in, and into which the 
 necessary volume of water can also be admitted in adjustable proportions. 
 The excavated material and requisite quantity of water for pumping it away 
 are then mixed in the receiver, and the slurry thus formed is lifted by the 
 pump. 
 
 Trials with a 
 
 remodelled 
 
 lighter. 
 
 The receptacle wherein the excavated material is mixed with water is 
 suitably constructed for that purpose, and when working in compact ground 
 the work of excavation and mixing is assisted by pressure water, which can 
 be directed in powerful streams upon the exact spot where the ground is to be 
 excavated. This system of dredging seemed to be eminently adapted to the 
 existing requirements, and it was, therefore, proposed for adoption, on the 
 understanding, however, that its efficiency was to be first proved by pre¬ 
 liminary trials on a larger scale. 
 
 To carry out these experiments an existing steam lighter was recon¬ 
 structed and fitted up as a dredger by Friihling on the system invented by 
 him, secured by patents. 
 
 The lighter was of the usual construction, had stowage room of 150 
 
35 
 
 cubic meters capacity, was fitted with a compound engine, with surface 
 condensation, of 185 indicated H.P., a boiler with 65 square meters heating 
 surface working at 8 atmospheres excess pressure, 2 hopper-winches, and a 
 simple anchor winch worked by hand gear. 
 
 To turn her into a dredger, the additional fittings consisted of a suction 
 pump with direct acting engine, suction and delivery pipes for dredging, pipes 
 for water for mixing purposes, pump and piping for forcing pressure water, a 
 dredging head, a dredging crane combined with two stern winches, and a 
 double forward winch. 
 
 The dredging pump was a centrifugal pump with impeller 900 milli¬ 
 meters in diameter, and made 200 revolutions per minute. It was driven by 
 a direct coupled engine of 75 I.H.P. 
 
 The dredging conduit consisted of a plate girder with two fixed arms. 
 The two arras enclosed the hull between them, reaching up on either side, and 
 turned round pivots fixed to the sides of the hull. The other end of the girder 
 was suspended by wire ropes, working round pulleys, from the dredger crane 
 which was fixed on the deck abaft. The dredging head, of special construc¬ 
 tion, was fixed underneath the lower end of the ladder, and two pipes led 
 from it on to the deck. The suction pipe was fixed on the port side, and ran 
 up on one arm to the pump. The other arm, on the starboard side, carried 
 two more pipes, one for conveying the pressure water to the dredging head, 
 the other the water necessary for mixing the slurry in the receiver. The 
 pressure water, as already stated, was supplied by a special force pump. The 
 other pipe, conveying water to the receiver for mixing with the dredgings, 
 had an inlet close to the end of the arm, the size of the opening of which could 
 be opened and closed and regulated by a valve from the deck, and more or less 
 water admitted to the pipe at will. The water to be conveyed to the mixer 
 and receiver was sucked in by the sucking action of the dredging pump. 
 
 The dredging head was 3.5 meters broad. When about to dredge, it 
 was lowered by the crane into position, and was dragged along the bottom by 
 the dredger. 
 
 The dredger was moved ahead by two powerful forward winches, and 
 made a straight cut 3.6 meters broad; arrived at the end of the cut, it was 
 hauled back by the two stern winches, and moving forward again made a 
 second, deeper cut or changed its position and made a fresh cut sideways. 
 
 The excavated material was delivered by the pump into barges lying 
 alongside, or was forced through a delivery pipe line, 100 meters long, and 
 deposited at convenient places on the banks. 
 
 The dredger started work in the autumn of 1900, and was subjected to 
 extensive trials. After it had undergone various improvements and its crew 
 had been properly trained to the work, the dredger worked with perfect satis¬ 
 faction both in mud and in sand, and is still continuously employed in main¬ 
 tenance work on the canal. 
 
 The work performed by the dredger, considering the small power of the 
 
36 
 
 pump, is truly remarkable. It can load a scow of 150 cubic meters capacity 
 in 15 minutes. Working in mud, the dredger delivers the excavated material 
 in such a state of consistency that, if caught up in a tub at the mouth of the 
 delivery pipe, it forms a heap that will stand for hours without running off. 
 According to the density of the mud, when deposited, it contains from 60 to 
 90 per cent, of excavated solid material in its mass. 
 
 When excavating fine sand the work of the dredger also compares 
 favorably with that performed by other suction dredgers, though the work 
 done in this case did not give such good results as when excavating mud. 
 When dealing with fine sand, the volume of slurry delivered by the dredger 
 only contained about 20 per cent, of excavated material in its mass. 
 
 After lengthy trials and numerous alterations in the shape of the 
 excavating head, the dredger now works as satisfactorily in sand as in mud. 
 The quantity of sand delivered in the slurry can now be increased in propor¬ 
 tion to the power of the pump, and from 40 to 50 per cent, of it can be attained 
 without difficulty. 
 
 H view of the satisfactory results attained during the trial working, 
 
 &ClOJ)v0Cl ctuCl 
 
 Mcoiawa built Fruhling’s system of dredging has been definitely adopted for the newly pro¬ 
 jected dredger Nicolmis, which has been designed in accordance with the 
 special requirements of the Emperor William Canal already mentioned, and 
 the experience gained during the experiments has been duly utilized in work¬ 
 ing out its details. 
 
 The design, construction and delivery, fully equipped for the work, was 
 entrusted to Eegierungs-Baumeister Friihling, of Brunswick. The dredger 
 was built in the course of 1900 and 1901, delivered in September 1901 and set 
 to work, 
 
 Description of The equipment for dredging has been arranged in a manner similar to 
 
 that adopted on the experimental dredger, with the exception that the arms 
 of the ladder and the various pipes have been combined into one whole, and 
 are carried up through a gap in the centre instead of at the sides of the hull. 
 The object of this alteration was to provide better protection for the various 
 conduits, to give the dredger more mobility, and to enable other barges, 
 scows and boats to lie alongside more conveniently. 
 
 The dredging conduit is formed by a box girder, of quadrangular cross- 
 section, which has an enlargement at its lower end, and rests on a horizontal 
 shaft at its upper end. The dredging head is fixed to the enlargement at the 
 lower end, and the box girder rests, by means of the shaft at its upper end, in 
 the central gap on plummer blocks. 
 
 The construction of the dredging head is similar to that on the experi¬ 
 mental dredger. 
 
 The suction pipe is led on the port side of the dredging head, through 
 the enlargement, up through the inside of the box girder. It consists of a 400- 
 millimeter tube which ends in the horizontal shaft on the box girder in a 
 
37 
 
 cylinder which surrounds a similarly shaped junction pipe, leading to the 
 suction pump. 
 
 The water intended for mixing with the excavated material is led 
 down through the inside space left unoccupied by the suction pipe. For this 
 purpose the upper end of the box girder is closed by a diaphragm, and inlet 
 holes are provided in the sides of the girder for the admission of water. 
 These inlet holes can be opened and closed at will by movable louvres worked 
 from the deck. 
 
 The piping for conveying pressure water to the mixing chamber is car¬ 
 ried on the top plate of the box girder and is connected with the force pump 
 by movable pipes. The piping consists of three pipes laid side by side and 
 leading down to the dredging head, where they branch off into a number of 
 single pipes, some of which lead to the cutting edge of the head, others to the 
 interior, where they can assist the cutting apparatus at will in loosening the 
 ground with pressure water when working in stiff soil. 
 
 The force pump delivering pressure water is a direct acting Blake pump 
 of 40 H.P. 
 
 The dredging pump has an impeller of 1,150 millimeters diameter, is 
 driven direct by a compound engine of 150 H.P., and makes from 200 to 250 
 revolutions per minute. The pump delivers the excavated material through a 
 force pipe laid along the deck into the hold of the dredger, or through lateral 
 overflow pipes into scows moored alongside the dredger, or through an exten¬ 
 sion of the delivery pipe to a distance of 200 meters, and up to a height of 5 
 meters on the banks of the canal sideways. 
 
 The whole dredging conduit is suspended from a powerful crane fixed 
 abaft on the deck. This crane can lift 20 tons at a speed of 3 meters per min¬ 
 ute, and forms at the same time a stiff connection between the two stern 
 halves of the hull of the dredger. The dredging conduit resting in the central 
 gap is removable, and the whole conduit can be lifted out of the gap and 
 hoisted above deck. When at work the dredger is generally propelled by 
 screws, without any chains. For this purpose there are, besides the engines 
 working the pumps, two special engines, of 120 H. P. each, provided for work¬ 
 ing the propellers. These can propel the dredger at a speed of 16 kilometers 
 per hour unloaded, and at 12 kilometers when loaded. When excavating 
 ground of medium stiffness, the dredger can travel forward at a sufficient 
 speed to enable the dredging head to cut just sufficient material; that is, the 
 dredging head will excavate as much material in front as the pump will be 
 able to remove from the mixing chamber behind. 
 
 The dredging of the bottom is done in this case also in long strips, 3.5 
 meters wide. After leaving off work and returning from the dumping ground, 
 or when starting work on a new site, the dredger can take up its position with¬ 
 out difficulty with the help of convenient land marks. Being able to move 
 the dredger forward, when at work, by means of propellers only, and without 
 any chains, has its special advantages, when working near the entrance of the 
 
38 
 
 canal, as it does not interfere with navigation, and removes all dangers arising 
 from the use of chains in dredger working. This arrangement has, besides, 
 the advantage of increasing the quantity of work done by the dredger, because 
 a great deal of time is usually lost in dropping and picking up the chains, 
 when working with other kinds of dredgers, which time can be saved com¬ 
 pletely now and more profitably employed in doing useful work. 
 
 The dredger is provided with compartments for loading the excavated 
 material; it is constructed as a hopper dredger. It was advisable to adopt this 
 construction in view of the special conditions obtaining at Brunsbiittel (at the 
 canal entrance), which necessitated the adoption of some method of dredging 
 that was to be as simple as possible, and could be effected by employing a 
 single boat only. All three compartments together will hold 400 cubic meters; 
 there being two of 100 cubic meters each, and one of 200 cubic meters capacity. 
 The two smaller holds are one on either side of the central gap or slit, and the 
 large one in front of the engine room and stokehold, which are placed amid¬ 
 ships. 
 
 Such a distribution of the holds makes it possible to properly adjust the 
 loading of the boat and to distribute the material uniformly, so that the 
 dredger, whether loaded or empty, will always float on an even keel. 
 
 The dredger is emptied through hoppers in the bottom, which are opened 
 and closed by four steam winches placed on deck. 
 
 There is besides a contrivance by which the material in the holds can be 
 lifted by the suction pump and delivered on to the banks. The dredger is fitted 
 also with an elevator apparatus. 
 
 These equipments also were found necessary to suit the working to the 
 special conditions on the Emperor William Canal, as there are very few places 
 along its route where the hoppers can discharge the excavated material, and 
 special provisions had to be made, therefore, to be able to deposit the dredgings 
 at convenient places anywhere on the banks direct from the dredger. 
 
 The elevator equipment provided for this purpose consists of three pipe 
 conduits built into the hull and leading to the suction pump. The pipes run 
 alongside the holds and have a number of openings closed by flaps, leading to 
 the holds. The dredgings in the holds can be exhausted through these 
 openings, which being distributed all over the bottoms of the holds render it 
 possible to empty the three compartments gradually and uniformly all over 
 their areas. In case of the dredgings in the holds having become solidifled 
 they can be remixed with water before the material is lifted by the suction 
 pump, for which purpose there are four other tubes provided besides the three 
 suction pipes already mentioned. The four pipes for the delivery of the water 
 required for mixing have also openings into the holds, which are placed 
 opposite the inlets to the suction pipes. 
 
 The sucking action of the pump produces a stream running across the 
 hold from the delivery to the suction pipes, which loosens the deposited 
 material in the hold and carries it away with it. The loosening can be 
 
39 
 
 assisted by pressure water, which can be conveyed down special tubes into the 
 waterpipes and intensifies the streams of water across the holds. 
 
 This arrangement which is also the invention of Regierungs-Baumeister 
 Friihling, and has been patented, has also answered very well. 
 
 The hull of the dredger is 46.68 meters long by 8.48 meters beam, and 
 3.7 meters deep. These dimensions have been adopted to suit the cross-section 
 of the canal, so that the dredger can easily turn round and manoeuvre about 
 on the canal. In view of these requirements, the dimensions given above could 
 not very well be exceeded. 
 
 Over and above the machinery and equipment already mentioned, there 
 are also on board a central condensing apparatus with forewarmer, an electric 
 light installation for arc and glow lamps and projectors, a steam steering gear 
 and the usual auxiliary machinery. 
 
 There is besides on deck a powerful double forward winch, which can 
 jnoyejbhe dredger forward at a speed of 10 meters per minute and exert a pull 
 of 16 tons. This is provided for the purpose of hauling the dredger forward, 
 when it is intended to work with chains and without propellers. Steam is 
 supplied by 2 tubular boilers working at a pressure of 8 atmospheres above 
 atmospheric pressure, and having a heating surface of 110 square meters each. 
 
 The consumption of coals is 0.35 ton per hour while dredging, and 0.24 ton 
 when steaming with full load. 
 
 In order to enable the dredger to fulfil its subsidiary duties as a break- use as break¬ 
 down floating derrick and salvage boat, it is fitted in a convenient manner deS:k°and^ 
 with all the necessary equipment for such purposes, as, e. g., with ample 
 pumping power, etc. The powerful crane can be used in case of break-downs 
 and for raising wreckage; and, as already stated, there is also the possibility of 
 self-filling and self-clearing the holds in the boat. 
 
 The crew consists of the captain, cockswain, 3 sailors, cook, 2 engineers 
 and 3 stokers; 11 men in all. 
 
 The efficiency of the work done by the dredger as regards consistency work 
 of the excavated material and proportion of solid matter contained in 
 dredgings is the same as that of the experimental dredger. Owing to the use 
 of a more powerful pump, the quantity of work done by the new dredger is, of 
 course, greater. When working at the canal entrance near Brunsbiittel, the 
 holds of 400 cubic meters capacity are upon an average filled in 16 minutes. 
 
 The excavated material is then taken away to a distance of 3 kilometers and 
 discharged through the hoppers. Working ten hours the dredger can in this 
 manner make 13 such full trips on an average, including any delays by navi¬ 
 gation. The quantity of work done in excavation can not, owing to local 
 conditions, be arrived at in any other way than by measuring the volume of 
 material deposited in the holds. Deducting from the cubic capacity of the 
 holds 33 per cent, on account of incomplete filling and for increase in bulk, the 
 quantity of earthwork removed by the dredger under above-mentioned work¬ 
 ing conditions may be reckoned in round figures at 1,000 cubic meters per 
 
40 
 
 hour, and the day’s work at ten working hours, consisting of excavation, 
 carrying off the dredgings to a distance of 3 kilometers and discharging them 
 through the hoppers at 3,500 cubic meters. 
 
 The working expenses of the dredger amount tc 150 marks per day upon 
 an average. 
 
 Calculations have also been made with regard to the specific gravity of 
 tlje, excavated material. 
 
 According to the conditions prevailing at Brunsbiittel it has been found 
 that the dredger can perform the greatest amount of work if the specific 
 gravity of the dredgings is kept down to 1.275. The principal bulk of the mud, 
 which has to be dredged at Brunsbiittel to standard cross-section, as it lies at 
 the bottom, that is, before it has time to consolidate completely, has an average 
 specific gravity of about 1.3 or 1.33 respectively. At greater depths this increases 
 to 1.4, and even as much as 1.6. According to these weights, the percentage 
 of solid material contained in dredgings of a specific gravity of 1.275 woulfi. 
 amount to 90 per cent., or 83 per cent., or 68 per cent, or 46 per cent, 
 respectively. 
 
 Before the dredger Nicolaus started work, the necessary dredging to 
 be done at the canal entrance was performed by a large bucket dredger and 
 three steam hopper-barges. Working under similar conditions as those upon 
 which the work done by the dredger Nicolaus has been computed above, 
 the four boats excavated 1,500 cubic meters only per day, and entailed a daily 
 w'orking expenditure of about 380 marks in round figures. 
 
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