3M6 V #^o fA\ >^' :, % A3 /?], A MONOMOY AND ITS SHOALS. Fkom Annual Kepoet of Massachusetts Boakd OF Harbor and Land Commissioners FOR THE Year 1886. \\zv-^i r -i,- BOSTON : WRIGHT & POTTER PRINTING CO., STATE PRINTERS, 18 Post Office Square. 1887. AUG 30 mi MONOMOY AND ITS SHOALS. By the courtesy of Mr. F. M. Thorn, Superintendent of the United States Coast and Geodetic Survey, the Board i8 enal)led to present a very able and interesting report, re- cently made to that department by Prof. Henry Mitchell, concerning Monomoy audits Shoals, — a copy of which has, upon request, been furnished for publication in this report. Monomoy, it need hardly be said, is the long, narrow peninsula which projects southward from the shore of the town of Chatham, at the elbow of Cape Cod, and points towards Nantucket Great Point, which, in turn, stretches northward as if to meet it. Between these two points is the easterly entrance to Nantucket and Vineyard Sounds, through which, as Professor Mitchell says, "about 30,000 vessels pass annually, and occasionally 300 in a single day." In this great highway of commerce, around Monomoy Point and between it and Great Point, lie the Shoals of which the report treats. The purpose of the report is to show the changes — the shifting of position and growth in volume — of Monomoy and its Shoals during the last century. The discussion of the data available for a comparison of their former with their present location and l)ulk, and the methods of investigation and deduction by which the results slated are arrived at, are fully given in the report, and are marked by the scientific knowledge, skill and acumen for which the writer of the report is distinguished. The results are surprising, and seem to furnish just occa- sion for alarm. " The present aspect of the case," says Professor Mitchell, " is very threatening to navigation." It 4 Monomoy and its Shoals. is not proposed, however, to anticipate the more full and Batisfactory statements of the report itself. A map accompanying the report of Professor Mitchell is appended to this report, and presents to the eye by distinctive colors the comparative position and dimensions of Monomoy and its Shoals as shown by a chart based upon a survey made by Capt. Paul Pinkham in 1784, the accuracy of which is vindicated by Professor Mitchell, and as shown by the United States Coast Survey chart issued in 1885. Another map, also received with the report in question and appended to this report, shows in like manner the increase of '^Handkerchief Shoal" between the years 1853 and 1874-75, by means of a comparison of the coast surveys made at those dates respectively. Monomoy and its Shoals. MO NO MO Y AND ITS SHOALS. BY PROF. HENRY MITCHELL. This peninsula, and the group of Shoals about it, present dangers that afTect the commerce between the States to a greater degree, l)erliaps, than any other obstructions ; for here, at the eastern entrance to Nantucket and Vine\"ard Sounds, pass about 30,000 vessels annually, and, occasionally, 300 in a single day, the raaxi- mum of the j-ear. These 300 vessels average 200 tons nieasure- raent, giving a total of 60,000 tons, and represent, with cargo, three millions of dollars. These vessels not onl}' run the gantlet among these natural dangers, but they endanger each other by crowding into the fair- ways. The principal avenue, Butler's Hole, has only half the width that it had a centur}' ago, and its course has of late 3'ears very materially changed. Enery foot of loklth, where safety is assured, has a value; and, if the limits of the Shoals could be accurately defined, there would be a great reduction in the real danger, and — most of all — in the fear of danger, which delays the fleet in thick weather. In the measure that we can furnish the coaster with accurate charts and marks of this localit}', we reduce his danger and his fears which tax the community. The real source of trouble is the constant shifting of these Shoals, and their growth. We speak within the truth when we assert that these Shoals have doubled their volume in the last centurj', and that they have moved a mile in the average. The worst of it is that the movement is ver}" far from uniform in rate or directions for ditferent members of the group. Tills neighborhood was designated by Champlain (1605) " Cap Batturier" conve3'ing the impression by this name (and the context in his narrative) of a projecting region of breaking flats. At the present rate of building, the dry land of Monomoy could scarcely 6 Monomoy and its Shoals. have been half the present length at the time of Champlain ; and, if half the bulk, it must have been submerged. The present aspect of the ease is ver\' threatening to navigation. It looks as if a continuous breaker might extend from Monorao}' to Nantucket on the summit of the circus that is formed by r\)llock Kip, Great Uound Shoal and Great Point Rip, with their connections. The present broken wall has material enough in it to close the ship navigation, if this material should be strewn along more uniformly by some great storm, so as to connect more intimatel}' the chain of shoals. Moreover, there is plenty of new material supplied from the caving down of the Cape Cod shore. This caving has been ver}' active of late years, and forms the theme of reports in Appendices to the Annual Reports of the Coast Survey fur 1871 and 1873. The beach in front of the town of Chatham began to break up in 1871 ; and Professor Peirce, then Superintendent, ordered special surveys, which were executed b}' Assistant H. L. Marindin, and formed the subject of reports by myself. The earliest chart of this neighborhood, based upon anything like a regular survey, seems to be that of Capt. Paul Pinkham, made at the time that the present Light-house was being built upon Great Point Nantucket, in 1784. There are plenty of earlier charts, and there are sailing directions as far back as 1707 ; but the Paul Pinkham chart, on the whole, furnishes the first reliable testi- mony relative to the location of the Shoals at the entrance to the Vineyard Sound. I beg leave to offer an analysis of this testimony in detail, because of its importance, and because I fear that the chart of which 1 speak is likely, otherwise, to be confounded with a later one by the Blunts, assuming to be " Surveyed by Capt. Paul Pink- ham," which is siugularl}' out in its longitudes and in its distances. Tbe following appears upon the chart which I have used as m}' base of comparison : — A Chart of Nantucket Shoals surveyed by Capt. Paul Pinkham. Boston. Published and sold by \Vm. Norman, No. 75 Newbury St., February 16, 1791. To all whom it may concern : As there never has yet been published an accurate chart of Nantucket Shoals, These arc to certify that, when the Light-house was building on Nan- tucket point in 1784, this survey of the Shoals was made from the lantern (an oi)portunity never before had for so valuable a purpose) by Capt. Paul rinkliam and others, by the help of the best compasses and instru- ments that could be procured; and it has been proved by experience to be the most accunite chart ever olfered to the public of those dangerous Shoals (which are a terror to all navigators), which has been run by Monomoy and its Shoals. 7 with greatest safety, and is fully approved ; and that the publication of this chart, from its accuracy, cannot fail to be greatly beneficial to all navigators who may fall in with said Shoals, is the jud^'ment of us, [signed by] Jno. Cartwright, Jos'ii. Chase, Dan'l Collin, Nath'l Barnard, Jas. Backer, Wm. Coffin, Alex. Coffin, Jun., Thos. Delano. Nantucket, September 1, 1790. The many snrveyors who have attempted the survey of the Island of Nantucket, with the Shoals around it, and those charts have been jjub- lished, have from experience proved very incorrect and erroneous; more 2)articularly the Shoals which, lying at so great a distance from the land, have hitherto been laid down from information only. From htaice has arisen great errors and inaccuracies in the various charts published of those Shoals. On considering their dangerous situation, and the dread they are to all navigators who frequent the coast, as well as the great utility of a cor- rect cliart, I have been induced to use my best endeavors to obtain a new and accurate survey of the Shoals eastwardl}' of the Island, being taken from the Light-house on Nantucket Point in 1784, which eminence afforded a large and distant prospect of the Shoals, and from which their true bearing was had with precision and certainty. I hereby certify that the chait hereunto annexed, having been carefully examined by warrantable jiilots and navigators, and run by for some years with safety, is fully approved and by them certified. [Signed by] Peleg Coffin, Jr. Nantucket, September 1, 1790. The scale of this chart is about 1 : 137,780. It is the property of the Nantucket Athenaeum. It will be observed from the foregoing, that the claim of accu- racy particularly applies to the region seen from the Light-house, which is plotted on this old chart in latitude 41° 22', longitude 70° OOi'. It is the same Light-house that now stands, and is found, by latest survey, in 41° 23' 24" of latitude, and 70° 02' 45" of longitude. The former determination, on the Paul Pinkham chart, was, then, 2^ miles too far to the east-south-east. This error, however, need not concern us if we confine our inquiries to objects within sight of the Light-house ; and, first of all, we must seek those that have not changed, in order to orient ourselves. From Matthew Clark's chart of the neighborhood, endorsed b}' Osgood Carleton for the Boston Marine Society, the variation in the compass, at that time, seems to have been 6° 45' ; and, as the Paul Pinkham chart is evidently adjusted to the magnetic merid- ian, we have corrected for variation (as finally ascertained to be about 6J^° west) in the following bearings : — "Bishop and Clarks" Rocks, on Paul Pinkbam's chart, lie 15^ 8 Monomoy and its Shoals. nautical miles north 39^° west (true) from Great Point. Bishop and Clerks, on the most recent chart, lies 14| nautical miles north 39|° west of Great Point Light. The distances are measured from the old chart, not b}- its scale, but by minutes of latitude. I would remark here that the Paul Pinkham chart is a prett}' good projection, with ratio of 1 : 1.3 for longitude and latitude divisions ; but the scale of miles seems to be minutes of longitude. There is, upon the north-eastern portion of Tuckernuck, a sort of lagoon, at the head of which is quite a hill, upon which there was, at tlie time of Paul Pinkham, and still is, a group of houses. This hill, as represented upon the Coast Surve}' charts, lies west 30° south from Great Point Light, distant lOf nautical miles. Upon Paul Pinkham's chart, the head of the lagoon bears west 29J-° south, distant 11 nautical miles. The lagoon is known as East Pond, and the hill that rises at its head is a very conspicuous landmark. These three points, Bishop and Clerks, Tuckernuck and Great Point Light, are all that we can feel sure of as remaining un- changed. Great Round Shoal. — If we draw a circle through the three shoalest soundings upon the Coast Survey chart, we find its centre north 55° east from the Great Point Light-house, distant 7| miles. On the Paul Pinkham chart, it is represented by a circular line of dots, the centre of which is north G0|-° east of Great Point Light, 71- miles distant. Litt'e Bound Shoal. — The shoalest water lies north 39J-° east of Great Point Light, upon our most recent charts, distant 8 miles. Upon Paul Pinkham's chart, it is indicated b}' a circle of dots, the centre of which is north 40f° east from the Light, distant 7 miles. This shoal is not easily distinguished from the Stone Horse. '■'■Broken part of Pollock Pip" lies north 37^-° east, 11 i miles from the Light, on the Coast Survey chart, and north 35|-° east, 14^ miles, on Paul Pinkham's chart. This is rather beyond the range of vision from the Light-house, except for a wreck, and hard to distinguish, the shoals being numerous. Stone Horse. — The middle of this shoal, as well as can be de- termined, lies about in the same direction upon old and new charts, — north 22|-° east from Great Point Light. Its distance, according to Paul Pinkham's chart, was 8i nautical miles. It is now 7| miles ; that is, tlie shoal has moved about three-quarters of a mile towards the Light. Handkerchief Shoal. — This shoal has very much increased in size, and worked or extended downward. The least de[)th is the same (" 4 feet") now as upon Clark's map of 1798 ; but this figure Monomoy and its Shoals. 9 lies about one mile further from Great Point Light on Clark's chart than upon our own. The southern point of the shoal is given 8f miles north 2° west from Great Point Light, by Pink- ham, while by Clark it is 7^ miles due north, and upon the recent Coast Survey chart 6 J miles north 7J° west. The northern or north-eastern portion of the shoal has not essentially changed, being the same for Pinkham, Clark and the Coast Survc}' ; but the growth southward has exceeded one mile in the past century. Upon both of the old charts (Pinkham's and Clark's), the sailing course for the ' ' North Channel " was laid down north of the Hand- kerchief, and ran across what is now dr}' land near the present Monomoy Light. Clark's representation of Monomoy indicates a great extent sub- ject to overiow, so that it is difficult to make comparisons between it and other plottings. Butler's Hole. — This most frequented channel was about 1^^ miles wide upon Pinkham's chart, one mile on Clark's, and little better than a half-mile at the time of the most recent surveys. As might have been expected, Butler's Hole has increased in depth as it has lost in width. We find nearly 20 fathoms on the site where the old charts gave 15 as the maximum depth. The present max- imum depth is 23i fathoms. Before entering upon the more modern history of this region, we must call attention to what we ma}' designate as the deep hole, indicated b}' the sounding of 24 fathoms upon Paul Pinkham's chart. This sounding is plotted 7^- nautical miles north 71;^'' east of Great Point Light. Capt. McBlair, in 1849, found 21^ fathoms at a distance of G miles north 79f° east, and Capt. Brownson, at Ihe margin of his survey of 1883, gives 20 fathoms and no bottom 7 miles north 77^° east, of Great Point Light. There seems to be no doubt that a gully of considerable extent exists, which our printed chart does not proi)crly represent ; and it is believed that this gully is a permanent feature, notwithstanding that our benrings differ from Paul Pinkham's very largely'. It must be borne in mind that the bearings of breaking shoals could be accurately taken from Great Point Light tower; but a deej) hole makes no sign. Tliis gully lies so near the proper track of the South Channel fleet, that its careful representation upon the chart would be a valuable guide to navigation ; while its absence from the chart, or entirely inadequate rendering, provides for disaster. Some vessel standing in from seaward in thick weather, may happen to cast her lead in this deep place, and, believing herself outside of all the shoals, sail on to her destruction. 10 Monomoy and its Shoals. There is reason to belieA'e that Great Round Shoal and this gully are to be found now just where the}' always have been. The sailing line on Paul Pinkham's chart of 1784, if plotted upon our own chart, lies very near the southern slope of this gull}', and between it and our most recent sailing line. But wh}' this gully should not fill up, in this region of strong tidal currents laden with sand, is a mystery. It might be worth while to take some current observations, and ascertain if a resultant occurs here, not elsewhere developed. Monomoy Point. — This is well defined on Desbarres' chart of 1777, and on Pinkham's of 1791 ; but, on Matthew Clark's chart of 1798, it is represented as if aioasJi. The distances across from Great Point to Monomo}' are 1777, On Desbarres' Chart, . . 14 nautical miles. 1784-91, " Paul Pinkham's " . . 11^ 1798, " Matthew Clarli's " . . lOJ 1868, " U. S. Coast Survey " . . 9J Matthew Clark's chart only assumes to be a correction of Desbarres', while Paul Pinkham's was from a new survey. There seems always to have been a shoal off the extreme point of Monomoy, known as " Egg Island " when dr3\ This shoal has sometimes attached itself to the end of Monomoy, but oftener has been separated by a deep slongh channel. If we ignore the slough channel that now separates the point of Monomoy from the Shovelful Shoal (the reappearing Egg Island in an advanced position), we reduce the distance across from Great Point to less than 9 nautical miles (1875). It should be noted here that Great Point Nantucket has lost, by fits and starts, considerable length. Paul Pinkham found the extreme point, in 1784, over 3,000 feet be3-ond the present Light- house, then in course of construction ; Prof. Henry L. Whiting's topographical survey of 1846, gives this distance 1.900 feet; and Assistant F. D. Granger, on his h3'drographic sheet of 1874, places the point (by a signal as near as possible to the high water breaker) about 1,600 feet from the Light- house. We have every reason, then, to believe that the dry land of Monomoy has extended southward tico miles during the past century.* * There is a mysterious chart in the archives of the Coast and Geodetic Survey, entitled " A Chart of George's Bank, including Cape Cod, Nantucket, and the Shoals lying on their coasts, surveyed by Capt. Paul Pinkham," and " published by Edmund Jil. lihint, 1797." This chart, ostensibly six years later than the "Chart of Nan- tucket Shoals " (which we found so valuable), is comparatively absurd. It is a vhoie degree out in longitude, and it gives for the distance from Great Point to Monomoy, sixteen minutes of latitude; and yet the bearing and distance of George's Shoal were more nearly correct than upon any previous chart. Its scale is about 1 : 400,000. Monomoy and Us Shoals. 11 The first survey of Monomo}- made by a professional topograplier, was that of Mr. Charles O. Boutelle, then attached to the Trigono- metrical Survey of Massachusetts, in 1840. At that time the Point lay 2,681 feet south, 3,837 feet west, of the Light-house then standing.* In l