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1899.) , MARINE REVIEW. ee NAVAL DRY DOCK AT BOSTON. THE LARGY CONORETE STRUCTURE FOR THE OONSTRUOTION OF WHIOH A CON- er TRAOT WAS AWARDED EARLY IN THE PRESENT YEAR AND tN WHIOH IS TO COST $1,025,000. The drawings herewith presented will convey to readers of the Review a fairly accurate idea of 'details of the construction of the new dry dock, for the construction of which at the Boston navy yard the secretary of the navy some months ago let the contract to O'Brien & Sheehan of New York, the price being $875,000 for the dock proper and $150,000 for elec- trial and other machinery, bringing the total up to $1,025,000. The draw- ings and description of the dock are reproduced from the Engineering News. It will be remembered that under the pressure of demand for more and larger dry docks for the ships of the "new navy," and attracted by the relative cheapness and speed of construction, the United 'States navy de- partment, about 1886, adopted timber as the material of construction for its dry docks. Between 1887 and 1897 docks of this type were built at New -Yertical Section Through Pump Well. Plan of Pump Well Grating Hemoved. ELEVATION AND7PLAN OF PUMPING PLANT. York, N orfolk, League island, Port Royal and Puget Sound; and the last Congress, in spite of the able argument for stone docks presented by the Present chief of the: bureau of yards and docks, provided for four more timber docks. The bill, however, did finally make a concession to the effect that the secretary of the navy might, in 'his discretion, 'build one of these docks of stone; provided thiat the cost of this stone dock would not exceed $1,025,000, or about 25 per cent in excess of the limiting cost of timber docks, fixed at $25,000 each. For a long time past Rear Admiral Endicott, chief of the bureau of yards and docks, and other well informed naval officials, have been doing excellent missionary work in the cause of Stone or concrete construction for government dry docks, and some of their very convincing arguments have been presented in the Marine Re- view from time to time. Firm in his convictions in this matter, it was only natural that Rear Admiral Endicott resorted to extreme measures in his pleadings with the navy department. As a result, the secretary of the navy €xercised the discretion granted him in the case of the Boston dock, and On Jan. 31, 1899, he invited proposals for stone, and stone and contcrete combined, for the dock at that yard. Several favorable proposals were re- ceived, and on Feb. 6, 1899, the contract for a concrete dock, with rubble filling and lined with cut granite, was awarded to the firm of O'Brien & Sheehan of New York city. x SS EU srwteeee cone pees -- This dock will'be completed within two and a half:years. Therborings made at the sitenofithe new dock show that at a depth ofiabout 25 feet below mean low water a 'bed of compact clay and gravel disoencountered, with some thin sand strata, possibly containing water. 2°The position*of the AA Pe kefe Oak Bilge Blocks Kee" £8x18X26 Oath Slide for : 7 Side Elevation. Front a Elevation. 3 {o\ ai fey | [aX | Wo HUNAN TT Plan' of Cast Iron Rack Bar. } ' "DETAILS OF BILGE BLOCKS. new dock is about midway between the old stone dry-dock, finished in 1833, and the larger-of the two "wet-basins,' and parallel to the old dock. The general dimensions of the dock will be as follows: : Se aaa far tes Feet. Inches Length on coping, from head to outer end of table...............788 0 Length on coping, from head to outer gate-sill 1.0... 750 0 Length on-fioor, from head to outer gate-sill.....:.........cc0ec000. 729 0 Length on floor, from head toinner abutment........ ._ .........689 0 Wid thion coping mod yee eye ate el ees 114 0 Wd thy OD HOON TIND Od yee sae cee tees sc ettecn tn et eee 72 0 Width on coping at abutment, least... cccece cceseseceeeeeeees 101 8% Width at entrance on mean high water level. ................. 0. 100 0 Depth from coping to mean high water 2 2 Depth from coping to floor, in body........ 2 Draught over, sill_at'mean high water... lees 0 the contract this dock is to be built of concrete, with rubble stone fillers, and lined with cut-stone masonry, as shown in the cross-section illustrated. Wihen the excavation has sufficiently ad- -- vanced so as to fully expose the character of the underlying material, the Under the terms of. jess eas pept yeti By eae | [Ror a nn ne mere ees nent se mes ~---------- ---- pe og" a | TT : ! eee . | ! | 51378 4ux3 VP | ! i341, pOvsset PL ar * oak "\ i 1 gf ee NR StS eB" |W | eee ena ' i Fs : : . 4 ES . Valve Sahih a = -- Ry) iM 5 y= + Fousset Pi Peat MP see Zar' NI ii Ht ne do BFL, 34, Bub i 7 ' a } ee : ei, wi PPE (a | IE, ge at : 4 | i oo i of East Pe OS at i ) i | aa: ae 5 i eee Pane : i itr 1 i "il 8 Bent Pie t i eset Base Line _ kU tak een a ay : OT ES lbs." ah op 15,55 IBS. Transverse Section, Le pare sus OW 0! a : 5 ' 6 Neat t Beir ye ata ee eee ee pee ye pean, Fig, 410 acres ' . Part Plan and ~-- Sections of Caisson : REP Port Top Plan. government will decide whether piles shall or shall not be used under the dock; the present borings, however, would indicate that the soil is suffi- ciently compact to'omit piling. A price for piling and framing, in accord- ance with plans made, was obtained in the bids submitted; to be separately considered. In addition to the dock, there will be a pump house, one story in height, built of granite, with steel roof trusses and a copper roof.