Seabulk is adding powerful and manoeuvrable tugs to its US Gulf coast fleet
Seabulk is modernising its fleet with new escort and ship-handling tugs for operations in US Gulf coastal ports. It has introduced two of these, built to the advanced Rotortug (ART) concept, to support ships in Mobile, Alabama. Nike was delivered Q4 2021 and Hermes in Q2 2022.
Both were built by Master Boat Builders in Coden, Alabama to an ART 90-98 design by Robert Allan Ltd (RAL), ABS class rules for escort and towing vessels and US Coast Guard standards for manoeuvring large ships into ports on the US Gulf.
“Hermes is the latest addition to our fleet and joins Nike, its sister ship commissioned from Master Boat Builders last year,” says Seabulk chief executive Daniel Thorogood.
ART incorporates the patented triple Z-drive Rotortugs concept, featuring omni-directional manoeuvrability and the benefits of a fully redundant and precise propulsion machinery configuration.
“The Rotortug concept offers increased redundancy for ship-handling, terminal support and escort towing, as well as enhanced crew safety,” says RAL. Seabulk now has five ARTs in its fleet.
Hermes has an overall length of 30 m, a beam of 13 m, a hull depth of around 5 m and a maximum draught of nearly 6 m. This 299-gt tug has a bollard pull of 87 tonnes and a free running speed of 13 knots.
This comes from its main propulsion, comprising three Caterpillar-manufactured Cat 3512E engines, each rated at 1,770 kW at 1,800 rpm, complying with US Environmental Protection Agency Tier 4 certification and driving three Schottel SRP 430 Z-drives with fixed-pitch propellers.
The electrical plant comprises two Caterpillar C7.1 diesel generator sets each with a power output of 118 ekW. These provide electricity for the accommodation for eight workers. The master and chief engineer cabins are located on the main deck with two double crew cabins located on the lower deck.
Hermes has deck machinery enabling ship handling over the bow or stern and towing over the stern. On the foredeck is a Jonrie Intertech Series 240 hydraulically driven, single-drum winch carrying 183 m of 8-in Samson Saturn 12 HMPE rope. This winch has a line pull of 25 tonnes at 0.5 m/s and has a 300-tonne brake.
On the aft deck is a Jonrie Intertech Series 500 hydraulically driven, double-drum winch with a line pull and brake, carrying 198 m of similar rope.
The towing drum, with a spooling gear, has a capacity of 640 m of 2.25-in steel wire with a line pull of 50 tonnes at 0.15 m/s and a 150-tonne brake.
For safe ship handling, Hermes has extensive fendering around its hull, consisting of a cylindrical and W-shaped fender at the bow and stern and D-shaped fendering along the port and starboard sides.
This ART tug also has fire-fighting equipment capable of delivering 681 m3/hr with a single FFS pump and monitor driven off the port main engine power take-off unit. Foam is carried in portable tanks loaded on deck when required. Hermes can carry 180 m3 of fuel oil and 19 m3 of potable water.
Master Boat Builders has also delivered one tug and is building a second with hybrid propulsion for Seabulk. In March, it completed Spartan with two Cat 3512E main engines, each producing 1,900 kW and complying with EPA Tier 4 emissions requirements, and two Berg MTA 628 azimuth thrusters.
Berg Propulsion also supplied its own VS3 variable frequency drives with motors, and its own hybrid control system. Berg’s design, supply and integration includes the switchboard with full power management plus control of the tug’s twin main engines.
