Modified anchor-handling tug/supply vessel in build to meet US Navy requirement
Warship Technology: May 2020
The deal is the US Navy’s execution of its fourth and fifth options for Gulf Island’s construction of five T-ATS vessels that will be built at the company’s facility in Houma, Louisiana. The US Navy has remaining options for three additional vessels.
The Navajo-class will provide ocean-going tug, salvage, and rescue capabilities to support fleet operations. The current capabilities are provided by three T-ATF 166 and two T-ARS 50 class ships, which reach the end of their expected service lives starting in 2020.
The new vessels will be capable of towing US Navy ships and will have 6,000ft2 of deck space for embarked systems. The tugs will be 263ft long, have a beam of 59ft and can carry a load of 1,796 tons.
The T-ATS is a multi-mission common hull platform based on a commercial anchor handling tug/supply (AHTS) vessel with a large, unobstructed deck that allows for the embarkation of a range of standalone/interchangeable systems.
The vessel is designed to be able to support missions including towing, salvage, rescue, oil spill response and humanitarian assistance and undertake wide area search and surveillance using unmanned underwater vehicles and unmanned aerial vehicles.
It is also designed to enable what the US Navy describes as ‘future rapid capability initiatives.’ The key requirements established by the US Navy included at least 5,000ft2 of deck space, dynamic positioning to DPS-2 standard, a bollard pull of 130 tons and 40-ton salvage crane.
The new vessels are based on the Wartsila VS 4612 AHTS vessel design. This design has a hullform with bulbous bow that provides excellent fuel efficiency and seakeeping and diesel mechanical propulsion plant with shaft generators for operational flexibility and redundancy.