Each of the vessels will have a length of 87.4 metres and breadth of 21 metres and they will be designed by Rolls Royce Marine under a £50m contract.
Based on Rolls Royce’s UT 731 CD design, the vessels will be equipped to handle anchors for oil rigs, tow rigs to location and also serve as supply vessels.
Rolls Royce Marine said the vessels can operate in challenging climatic conditions and deep waters to carry out rig manoeuvring operations in water up to 3,000 metres and be able to implement sub sea construction and installation work.
The vessels will be built according to DNV’s environmental class "Clean Design" and will be equipped with a bollard pull of approximately 260t and 24 000 bhp of power.
Rolls-Royce will also equip the vessels with an integrated equipment system, including deck machinery and vessel control systems.
The vessel pair will also be equipped with diesel electric hybrid propulsion systems to reduce fuel burn and CO2 emissions.
Farstad said the new vessels will be similar to the design of four vessels Langsten previously delivered to the company during 2009-2010 while two of the vessels are currently under construction at the same yard with scheduled delivery in 2013.
The steel hulls of the AHTS will be built in Romania while they will be outfitted at STX OSV’s Langsten shipyard in Tomrefjord, Norway.
Delivery of the vessels will take place during first quarter 2014.
With this latest order Farstad will have four AHTS and six PSV vessels under construction worth NOK 4.4bn ($763m) as part Farstad Shipping’s fleet renewal programme with a focus on deepwater operation.
Farstad Shipping currently operates a fleet 54 vessels including 30 AHTS, 21 PSV and 3 SUBSEA while 6 PSV and 4 AHTS are under construction.
Image: The vessels will be designed to Rolls Royce’s UT 731 CD and will have a length of 87.4 metres and breadth of 21 metres. Photo: TX OSV.