A pair of rotor tugs for Seabulk Towing, Trident and Triton, are being constructed at Master Boat Builders in Bayou La Batre, Ala. Both 98-by-43-foot boats are scheduled for delivery in early 2017.
They are the first Robert Allan-designed Advanced Rotortugs (ARTs) to be built and operated in the U.S. Damen has built two in Europe and three are being built at ASL Shipyard in Singapore. A rotor has three z-drive propulsion units configured in a triangle, as opposed to two stern-mounted z-drive units on an ASD tug.
According to Robert Allan Ltd., the omni-directional maneuverability and redundancy of three propulsion units provides increased security for ship handling and escort towing, as well as enhanced crew safety.
Rick Groen, CEO of Seabulk Towing, said the company decided to introduce the tugs into the U.S. fleet because it believes they represent the “next generation of highly maneuverable tugs that provide an ideal solution for LNG export terminals and other applications that demand safe moorings.” Seabulk Towing is a subsidiary of SEACOR Holdings Inc., which is headquartered in Fort Lauderdale, Fla.
Each rotor tug has two Schottel SRP 1210 z-drives forward and one drive aft. The units are driven by three 1,910-hp Caterpillar 3512C Tier 3 mains, with Alphatron controls in the pilothouse. Running speed is 12.5 knots and the bollard pull is a hefty 80 tons. Twin 150-kW Caterpillar auxiliary engines provide electrical power.
On the foredeck is a JonRie Intertech Series 230 hawser/escort winch outfitted with 450 feet of Samson rope. The aft deck is fitted with a JonRie Series 500 towing and hawser winch wound with 2,100 feet of 2.25-inch wire rope and 450 feet of Samson rope.
The new tugboats will be ABS classed Maltese Cross A1, AMS, UWILD, Unrestricted Navigation.