Hydrofoil SWASH CTVs
Danish operator World Offshore Marine has refined the design of its advanced crew transfer vessels and has two new designs under construction that it believes will revolutionise crew transfer operations writes Dag Pike.
The existing designs operated by WOM feature innovation SWASH hulls where a central hull operates on the SWATH principle combined with side hulls for stability. With the new designs that will shortly be operational the propulsion system has been improved to give more versatility and a hydrofoil system has been added to help reduce the hull movements.
The trimaran hull shape confers the ability to operate at high speed with reduced fuel consumption. This gives the new vessels a service speed of 25 knots and a 29-knot sprint speed. The SWASH type hull gives the vessels good seaworthiness and stability and WOM is confident that the vessels will be able to undertake transfers in sea states up to a significant wave height of 2.5m aided by the Soft Bow system that the company has developed.
The vessels are fitted with Humphree interceptors coupled to an automatic ride control system that helps to reduce pitch and roll. The innovative hydrofoil mounted at the bottom of the centre hull is adjustable and this helps to, reduce vessel motions. “The hydrofoil and the interceptors work together to optimise the trim of the vessel,” Lykke-Kjeldsen, Sales manager for WMO, explains. “Because the hydrofoil is adjustable, and its operation can be independently controlled to either side of the centre hull, it can be used to reduce rolling motions.” It can also provide 7 tonnes of lift to adjust the trim and compensate for cargo on the vessel’s 110 sq. metre foredeck.
For propulsion the PM5 has five Hamilton water jets, three in the centre hull that are powered by 736kW Scania diesels and each side hull has a single jet powered by a Visedo Electric motor. These electric motors are powered from a 640kW generator and a 42kW battery bank. For manoeuvring there are two 100kW bow thrusters
These new designs can transport 24 passengers in business class seats or alternatively accommodate 12 passengers in single cabins with the latter offering a 14 day at sea capability.