W&D Delivers Z-Drive FiFi Tug

Washburn & Doughty Associates, Inc. of East Boothbay, Maine delivered Bulldog, a 98 x 37 ft., 6,700 hp, Z Drive firefighting tug, to Crescent Towing of New Orleans, La. Bulldog provides ship-assist and escort services for LNG tankers at the Elba Island LNG re-gasification terminal in Savannah, Ga. Bulldog is a new Washburn & Doughty in-house design and the first tug built at the yard for Crescent Towing. Washburn & Doughty's Chief Naval Architect and Vice President, Bruce Washburn, drew on the company's experience designing and building Z-Drive Tugs for ship docking and LNG operations while designing the 98-ft. Tug. Since 1999, the company has designed and built 18 Z-Drive Tugs, six of which are used at LNG Terminals. With the 98-ft. design, Washburn & Doughty maintained a traditional look while providing 360-degree visibility in the pilothouse. Underwater, the vessel features a deep box skeg designed to enhance escorting without sacrificing maneuverability. Throughout the design process Washburn & Doughty received input from Crescent, Moran Towing Corporation, the shipping companies and their consultant, Greg Brooks. In addition, Washburn & Doughty contracted with Glosten Associates who analyzed the tug's escort capability from their escorting computer model. Glosten predicted that at 8 KTS the tug will have steering forces of 75.6 ST and braking forces of 116.2 ST. Bruce Doughty, Washburn & Doughty's President & CEO said, "We have worked on numerous tug bids for LNG operations lately and thereby become very familiar with what terminals and shippers are looking for in a vessel. Our 98-ft. tug addresses what LNG operations need in a tug, particularly as it pertains to power, maneuverability, escorting and firefighting capabilities." Bollard pull tests on January 10 in Newport News, Va., revealed: Forward Mode — 180,000 lbs. (90 Tons); Forward Mode Max — 182,000 lbs. (91 Tons). Firefighting 1 equipment includes two Caterpillar 3412C engines rated at 900 hp @ 2,100 rpm and Nijhuis HGTFI-1-250.500 pumps located in the engine room. The pumps supply two remote controlled FiFi 1 monitors mounted on the aft upper deck. Controls for the monitors are in the pilothouse and locally at the monitors. The firefighting system also includes a deluge sprinkler system and eight fire stations located on the main deck.

Bulldog is powered by two medium speed GE 7FDM12 main engines that each produce 3,350 hp @ 1,050 rpm. According to Bazemore, "The GE power units are remarkable and performing well." The propulsion system is completed by Rolls Royce model US255 Z Drives with 2800mm, 4 blade, stainless steel propellers. Bulldog is equipped with John Deere model 6068TFMGK-99, Tier 2 emissions certified, marine generator sets providing 99 kW @ 1,800 rpm, 208V 3 phase power. In the event that the on-line generator fails, the standby generator will automatically start and go on line. The generator experiencing the failure will be automatically shut down. The main switchboard provides for automatic paralleling of the generator sets and is integrated with the winch controls. The online generator provides sufficient power to operate the winch in normal (assist) mode. When high power (escort) mode is selected, the standby generator is automatically paralleled with the online generator. The bow is fitted with a Markey type DESF-48, 100 hp electric escort winch. The winch drum holds 750 ft. of nine in. synthetic line. The winch features line-pulls up to 365,000 lbs. @ 0- 8 fpm; line-speeds up to 600 FPM; and a drum brake holding capacity of 476,000 lbs utilizing an Eaton water cooled brake. A 15 hp Markey CEWC-60 electric stern hawser capstan is located on the aft deck and a 5 hp Markey CEP-40 electric messenger capstan is fitted on the foredeck. Bow fendering includes 12 x 14 in. rectangular molded rubber on the upper section; 16 in. soft loop on the middle section; and a "Turk's head" style fender on the lower section. 12 x14 in rubber D fender is fitted at the main deck on the sides and stern.