Vessel Management Services, a subsidiary of Crowley Maritime Corp.
, is building three Z-drive, Cat-powered prevention response tugs (PRT). The first 140-ft. vessel is scheduled to enter service in Prince William Sound, Alaska
, in February, 2000, with the other two following closely in April and June.
Dakota Creek Industries, Anacortes, Wash., is building the vessels, which were designed by Guido Perla & Associates, Seattle.
Propulsion will be provided by two Cat 3612s, each rated 5,096 bhp at 900 rpm. Two Aquamaster Z-drives, with 5.15:1 gear reduction will drive 138-in. diameter controllable pitch propellers inside nozzles. The vessels will have approximately 260,000 lbs. of bollard pull, and an estimated top speed of 15 knots.
The vessels' mission will include general purpose tug work, such as line-haul towing, tanker towing, staging pollution response barges and some ship handling and docking work. They are ABS certified for FIFI-1 firefighting, and equipped with boom reels for spill response.
The vessel features more than 10,000 bhp of steerable Z-drive propulsion and two appropriately sized deck winches: a Markey Machinery TDS-40 tow winch, with 2,500 ft. of 2.5-in. wire rope will be located aft, and a Markey WYWD-20-48 combination winch/windlass on the bow will carry 400 ft. of nine-in. synthetic fiber rope.
Auxiliary power will be provided by two Cat 3306B gensets, each rated 190 ekW at 1,800 rpm.