Harvey Energy is the first vessel in North America to be powered primarily by liquefied natural gas (LNG). The pioneering offshore supply vessel (OSV) started operations in March 2015, serving Shell in its deepwater offshore operations in the Gulf of Mexico.

Gulf Coast Shipyard Group (GCSG) is constructing two more vessels in the series for Harvey Gulf International Marine, in Mississippi. Harvey Gulf estimates that each vessel will save it approximately $2.4m a year on fuel costs.

The dual-fuelled OSV, using diesel as alternative fuel, is capable of operating for roughly seven days without refuelling. The vessel will load from Harvey Gulf’s new LNG bunkering facility at their terminal in Port Fourchon, which is set to open in July 2015, and deliver equipment and drilling fluids to a number of offshore platforms.

Horizon Spirit is a C9 class container ship owned by Horizon Lines. The vessel was commissioned in 1980. Major modification works were carried out on the vessel in 1990.

The LNG-fuelled vessel will meet the new sulphur and nitrogen oxide emissions regulations set for the North American emission control area (ECA). The new regulations, set to be effective from January 2016, require vessels operating in the ECA to meet a 0.1% fuel sulphur emissions limit.

The vessel has been assigned the +A1, OSV, +AMS, +DPS-2, +ACCU, UWILD, FFV-1, ENVIRO+, Green Passport (GP), GFS (dual-fuel diesel) E class notations by ABS.

Design details of Harvey Energy OSV

The vessel is based on the Vard Marine 1 311 design. It has an overall length of 310m, moulded breadth of 64m, design draft of 6.2m and deadweight of 5,150t.

"The OSV is constructed using certified environmentally-friendly materials."

Harvey Energy is capable of carrying 958m³ of diesel, 295m³ of LNG, 61m³ of fresh water, 2,601m³ of liquid mud, 246m³ of methanol and 290m³ of dry bulk. It provides accommodation for 42 persons and is further equipped with three additional sick berths.

The OSV is constructed using certified environmentally-friendly materials, is fitted with advanced alarms for its fuel tanks and containment systems, and uses Shell’s proprietary Gadinia 40 as its engine oil.

Harvey Energy engine and propulsion machinery details

The vessel is powered by three Wärtsilä 6L34DF dual-fuel gensets that provide 7.5MW of power. Fuel is supplied to the engines through Wärtsilä’s LNGPac gas storage and supply system. The vessel is further equipped with a 152kW emergency generator.

The propulsion machinery of the vessel includes fixed-pitch propellers fed through a variable-frequency drive (VFD), two azimuthing thrusters of 2,700kW each, and two bow thrusters of 280kW each.

The propulsion system provides the vessel with a top speed of 13kt.

"The propulsion system provides the vessel with a top speed of 13kt."

Contractors involved with North America’s first LNG-powered vessel

The five-year maintenance services for the vessel are being rendered by Wärtsilä, who, in addition to supplying the engines and the LNG storage and supply system, was also contracted to supply and install its control and communication centre (3C) integrated bridge, navigation and communication control system, and the complete electrical and automation system.

Lockheed Martin supplied the 250,000lbs cryogenic LNG storage tank, which was fabricated at its NASA Michoud assembly facility in New Orleans, Louisiana.

The natural gas couplings, dry-break fuel connection, and break-away safety couplings for the vessel were manufactured by Mann Tek and supplied by Bluewater Rubber & Gasket. The cryogenic hoses were supplied by Guteling, while Bestobell supplied its fireproofed globe and check valves.