Modutech Marine, Tacoma, Wash., has delivered the first of 25 tugs, designated Work Boat Medium, to the U.S. Navy. The first was delivered in December 2017 with the others to follow in regular deliveries through to December 2019.
The U.S. Navy has some spectacular vessels from submarines to high speed RIBs. It also has dedicated ports and support facilities worldwide. A practical reality of all of this is that the Navy requires efficient and handy boats to support the warhorses. To meet this requirement John Myers of the Seattle-based naval architect firm Hockema & Whalen and Associates has developed a 30'x15' tug, with a 5'6"-foot draft.
The engines turn nozzled 39"x36" propellers through ZF W325 gears with 3:1 reduction ratios. Cummins Marine photo
In order to handle some heavy pushing, the Navy has ordered the vessels to be powered by a pair of Cummins QSL 9 diesels each delivering 285 hp continuous duty. The engines turn nozzled 39"x36" propellers through ZF W325 gears with 3:1 reduction ratios. Triple shutter-type rudders are mounted behind each prop. The combined 570 hp will give the 30' tugs a 17,500-lbs. bollard pull. Between jobs, the boats will be capable of nine-knot speeds.
Tankage will include a 400-gal. fuel tank. On deck, a 400-lb. davit can be moved to port or starboard mounts as required. A pair of Bloom deck winches are mounted forward, port and starboard, so as to function with a pair of cheek blocks mounted alongside the pilothouse for making up to a barge with the push knees. Wide side decks provide a safe workspace for the deckhand. A towing bitt is mounted on the after deck. Heavy bollards are mounted on both sides for mooring and for working barges or other equipment on the hip. Lifting pad eyes are built into the tugs’ structure.
D-Rubber fendering surrounds the hull, including the chine, and is mounted on the push knees that extend below the waterline. The wheelhouse has overhead windows for working alongside ships. This series of boats have clearly been designed with careful attention to detail and thought to versatility of application and varied roles to which they may be assigned.
