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Trinity Delivers Second Cycloidal Tractor Tug; Launches Casino Boat

Trinity Industries Inc.'s subsidiary Halter Marine has been busy, delivering the Garth Foss—the second of two 155-foot (47.3-m), 8,000- hp enhanced tractor tugs equipped with cycloidal propulsion units— and launching theFlamingo Hilton, a 245-foot (74.7-m), 1,500-passenger riverboat casino.

Voith-Schneider Powers Tug The Garth Foss was delivered to Foss Maritime of Seattle, an^ preceded in November by an identical sistership, the Lindsey Foss.

The tugs, reportedly the world's largest and most powerful, are fitted with Voith-Schneider cycloidal propulsion units. The Garth Foss will work for BP Oil Shipping Co. escorting tankers in the Straits of Juan de Fuca and Puget Sound.

The Lindsey Foss is already working for Arco Marine, performing similar tasks.

The Voith-Schneider cycloidal propulsion system consists of two sets of five vertically oriented blades installed ahead of the tug's center. The system gives the tug 360° maneuverability and great ability to steer and stop tankers in the event of an emergency.

Foss Design Team primarily performed the design work for the two tugs.

Glosten Associates, Inc., a Seattlebased naval architectural firm, provided a contract design and prepared plans and specifications. Detailed design work was conducted by Trinity under Foss supervision, with additional assistance from Glosten. Foss selected tractor tugs equipped with cycloidal propulsion because of the need to provide high speed (12 knots plus), safe escort, and retardation and steering forces for loaded tankers during rough, open-water conditions.

"Cycloidal propulsion is relatively new to U.S. shipyards, but not to Trinity shipyards," said John Dane III, president of the Trinity Marine Group.

Technical details of the vessels were recently presented by Steve T. Scalzo, senior vice president of Foss Maritime, at the Royal Institution of Naval Architects in London. He said the nearly double-ended hulls have a pronounced shear to keep the decks dry, and a substantial shear strake to provide a foundation and bearing surface for fendering and bulwarks. The bulwarks were moved inward and canted inward to reduce contact with the vessel being assisted.

The superstructure was also kept well inboard to minimize the possibility of contact with the vessel being assisted, as well as all deck machinery, particularly in an obstruction- free zone at the stern.

The Voith-Schneider unit is driven by a pair of General Motors EMD ME 16-710-G7A diesels rated at 4,000-hp each turning through propulsion unit reduction gears. A turbo coupling between the engine and reduction gear replaces a clutch. The 475-grt vessel has a running conditionspeed of 14.5 knots, and carries 83,700 gallons of diesel fuel, 2,400 gallons of lube oil and 4,000 gallons of fresh water.

A 345-sq.-ft. skeg at the stern helps the tug to steer and stop a moving tanker.

A tractor tug fastened to a ship is operated stern first, and can shear off at an angle using the skeg in combination to produce steering and stopping forces greatly in excess of the tug's static bollard pull.

The tugs feature second generation winches with high braking capacity and fast line recovery.

 
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