New LNG-burning crew boat offers high-speed, stable W2W platform
Working collaboratively with Australian naval architect and marine engineering firm Incat Crowther, ST Engineering has developed a high-speed, LNG-fuelled crew boat. The vessel features a wave-piercing semi-SWATH hull form, allowing the 76-m vessel to transit at high speed with low hull motions. For crew comfort, the fast crew boat is fitted with a ride control system comprising a pair of forward-mounted active T-foils and aft-mounted active Interceptors. These technologies enable comfortable high-speed transit and provide a platform to operate a broad range of walk-to-work (W2W) solutions from its rear deck, when coupled with a dynamic positioning class 2 system.
Propulsion power is supplied by four 10-cylinder, dual-fuel engines that drive four waterjets, providing a maximum speed of 40 knots and a cruising speed of 34 knots.
The interior has two classes of seating for 150 passengers and can comfortably house 30 passengers in single cabins.
Using LNG as a fuel is an unusual choice for a crew boat, but ST Engineering marine sector senior vice president, marketing and business development Michael Bell says several factors weighed into the decision, notably LNG’s cleaner burning nature as compared to traditional bunker fuels. “Tighter emission regulations from IMO are driving changes in fuel requirements, as the industry works towards lowering SOx emissions,” says Mr Bell. “Compared to traditional marine fuel, LNG has a lower carbon content, making it the fuel of choice for many shipowners and operators to meet the tighter regulations.”
“LNG is the fuel of choice to meet tighter regulations”
Adds Mr Bell: “Over the medium- and long-term outlook, LNG is proven to be more cost effective than marine diesel in most markets.”
ST Engineering’s US shipyard, VT Halter Marine in Pascagoula, Mississippi, is well-experienced in building LNG-fuelled vessels, constructing two container roll-on roll-off vessels for Crowley Maritime for service between Jacksonville, Florida and San Juan, Puerto Rico. The shipyard is also building the first LNG bunkering and transport articulated tug barge (ATB) unit for Q-LNG, LLC for service in the US southeast and Caribbean.
Mr Bell says the crew boat design concept was developed with oil and gas and offshore renewables customers in mind, taking into account regional factors from Europe, Asia, Middle East and the Americas.
“For example, during the Asia monsoon season, our dual-fuel LNG catamaran fast crew boat can still enable high speed yet comfortable transit despite high significant wave heights,” he says. “Also, we understand the inherent risks associated with working in an offshore environment. Our concept provides safe transfer of people via gangways, even in poor weather.”
ST Engineering is also evaluating alternative fuels and technologies like hydrogen fuel cells and pure electric propulsion.
“We are constantly seeking innovative ways to increase cost and power efficiency, while lowering emissions for our customers’ vessels,” says Mr Bell. “We have specifically evaluated hybrid-electric propulsion, not only for main propulsion, but also as an alternative to running main engines during idle and stand-off periods, since these are the times where the engine runs most inefficiently and produces high exhaust emissions.”
He adds that there is an option to include electric inputs to gearboxes on the crew boat to enable diesel-electric operation in a standoff mode. He says this will enable shutdown of the main engines and the ability to operate on the basic generator set-driven electric motors for more sustainable shipping.