Harvey Gulf International Marine has ordered the construction of an additional Dual Fuel Offshore Supply Vessel TY Offshore, bringing Harvey Gulf’s total order to six.

TY Offshore is building the six vessels at its Gulfport, Miss., shipyard.

TY Offshore said the 302-foot-by-64-foot vessel and other orders position Harvey Gulf as the largest owner/operator of clean-burning liquefied offshore support vessels in the world.

“We are the only company in America building offshore supply vessels utilizing liquefied natural gas as its fuel source regardless of the fact that these vessels have a construction cost of 20 percent higher than a conventional offshore supply vessel,” Harvey Gulf CEO Shane J. Guidry said in a statement.

Founded in 1955, Harvey Gulf International Marine specializes in towing drilling rigs and providing offshore supply and multi-purpose support vessels for deepwater operations in the U.S. Gulf of Mexico.