Harvey Gulf International Marine has chartered two more LNG-powered offshore supply vessels.

Harvey Gulf announced the deal this week. The five-year charters will commence upon delivery of the Harvey Freedom and Harvey America, the fourth and fifth in a class of six LNG-powered OSVs the company has built. Harvey Gulf said that the charters "come during one of the softest OSV markets in decades, demonstrating a clear advantage for clean burning LNG power."

The first three LNG OSVs, the Harvey Energy, Harvey Power and soon-to-be-delivered Harvey Liberty, have been chartered by Shell to work in the Gulf of Mexico.

Harvey has demonstrated a strong commitment to LNG fuel, opening what it calls the first marine liquefied natural gas fueling terminal in North America in Port Fourchon, La., earlier this year.

The first ship to be bunkered at the new terminal was the Harvey Energy, named along with sister ship Harvey Power as the 2015 Boat of the Year by WorkBoat Magazine for their innovative LNG design.

Also last week, Harvey Gulf was named Shipowner of the Year by the U.K.-based Offshore Support Journal at a ceremony in London.