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Tuesday, 16 February 2016

Preliminary design for an American harbour tug dated 20 March 1918


Drawing S 584-127 made by the Bureau of Construction and Repair for a wood-built harbour tug based on designs for a similar merchant tug provided by the firm of Gielow and Orr. The available technical specifications are quite summary. Normal displacement of 215 tons and as dimensions 76.0 (designers waterline)-86.0 (overall) x 20.0 (moulded on waterline)-20.6 (extreme on waterline) x 7.6 and a freeboard of 4.0 (at side M.P.)-4.3 (freeboard maximum at AP)-7.0 (freeboard maximum stem) feet. Coefficients at normal displacement 0.665 (block)-0.785 (longitudinal)-0.835 (midship). Water tank forwards frames 6 to 14=14 ton or 506 cubic feet and water tank aft frames 31 to 38=933 cubic feet or 25,9 ton. Coal bunkers situated in the sides of the boiler room (dimensions 20.3 x 11.0 feet and a total machine space 31.3”) with a maximum bunker capacity of 1.406,5 cubic feet or at 43 cubic feet per ton for each bunker 16,35 ton. Vertical single cylinder elevated type machinery.

Source the so-called Spring Styles Book 1 (March 1911-September 1925). Naval History and Heritage Command. Lot S-584. Preliminary designs prepared by mostly civilians working at the Bureau of Construction and Repair (succeeded by the Bureau of Ships nowadays the Naval Sea Systems Command) under supervision of naval architects of the Navy Construction Corps. A major part of the drawings is presented to the General Board which adviced the Secretary of the Navy.