Navy maritime surface craft sets speed record on algal fuel blend

By Bryan Sims | December 15, 2011

In a continued effort to test and validate advanced biofuel utilization in both air and sea crafts, the U.S. Navy successfully concluded its final demonstration of the year Dec. 7-9 with operational testing of a 50/50 blend of algae-derived hydroprocessed oil and petroleum-based F-76 fuel in a landing craft air cushion (LCAC) amphibious transport vehicle.

The tests also marked the fastest speed achieved to date by a Navy surface craft using alternative fuel blends as the LCAC 91 reached an impressive 50 knots (57.5 mph). The fastest recorded speed using a 50/50 algal blend in previous testing was 44.5 knots (51.2 mph) by the experimental Riverine Command Boat (RCB-X) in October 2010 at Naval Base Norfolk, Va.

“This demonstration is another Wright Brothers-moment for the Navy,” said Rear Admiral Philip Cullom, director, Chief of Naval Operations Energy and Environmental Readiness Division. “We have shown that we can achieve more than 50 knots on the water and Mach 1.7 in the air—all on biofuel blends.”

LCACs, which move elements of a Marine Air/Ground Task Force, feature four gas turbine engines and two generators that traditionally run on NATO F76 or NATO F44. They also have a 7,000-gallon fuel capacity, an average range of 200 nautical miles, and can carry up to 150,000 pounds of weapons systems, equipment, cargo and/or personnel.

“The test run on the 50/50 alternative fuel mix was very successful,” said Scott Feenstra, mission director for the LCAC at the Naval Surface Warfare Center (NSWC) Panama City, Fla., Division. “LCAC 91 performed without issue. The operators were able to use high power; and reported that the craft handled beautifully and without problems.”

For the test, according to Richard Leung, Naval Sea Systems Command’s Navy Fuels Engineering Manager, the craft operated out in the Gulf of Mexico on two different fuel configurations in order to compare operations as powered by each fuel type.

“After draining the diesel, LCAC 91 received approximately 5,000 gallons of the 50/50 algal blend,” Leung said. “We assessed the engine performance capabilities on the biofuel blend and collected data on engine torque, acceleration rates, craft speed, fuel flow rates, propeller pitch, compressor discharge pressure and inlet and exhaust gas temperatures.”

Mechanical engineers bore scoped the engines and collected the technical data. LCAC operators then provided input on how the craft performed and operated.

“We are going to compare how the engines performed during the test both on the straight diesel and on the 50/50 mix,” said Ben Canilang, mechanical engineer for the Naval Surface Warfare Center Carderock’s Naval Ship Systems Engineering Station in Philadelphia. “Results from the comparison will help us assess the performance of the fuel.”

Meeting the secretary of the Navy’s directive for a drop-in fuel replacement, no changes were required to the LCAC or fueling equipment infrastructures for the test.