Faced with rising fuel prices and diminishing oil reserves, the US Navy is rebuilding itself with a greener fleet. The>USS Makin Island is the poster child of this restructuring, having cut its fuel consumption in half with an engine overhaul.
The USS Makin Island is the eighth and final WASP-class Amphibious Assault Ship in the US armada and the second to bear the name of the famous US raid on the Japanese-held island during World War II. However, that’s generally where the similarities between the Makin Island and her sister ships end. Unlike other WASP-class vessels, which rely on antiquated steam power, Makin Island sports a state-of-the-art electric-hybrid propulsion system.
The Makin Island is outfitted with a pair of General Electric LM2500+ gas turbines, a pair of electromotors, and six diesel generators. Propulsion duties are split between the gas turbines and the diesel-powered electric motors, dubbed the auxiliary propulsion motor (APM), with the former used for high-speed travel (it tops out at 25 knots) and the latter for low-speed maneuvers (anything under 12 knots). The electric motors are employed about 70 per cent of the time (since the diesel engines are more fuel efficient and produce fewer emissions) and the gas turbines enabled only sparingly, which reduces the ship’s fossil fuel consumption by half.
During its seven month maiden voyage, during which it circumnavigated the Earth carrying a full compliment of 1200 Marines and 1000 Navy sailors, 29 helicopters and 6 Harrier jets, the USS Makin Island burned just $US15 million of its $US33 million allotted for fuel costs. On average, the Makin Island uses 56,781 litres of fuel a day, versus 130,000 to 150,000 litres consumed by its old steam engine. Naval brass hopes to save close to $US250 million in fuel costs over the life of the ship.
What’s more, the new APM allows the Makin Island to deploy faster, requires a smaller crew to operate, and can remain active longer than its steam-powered counterparts. See, conventional steam propulsion drives may require up to three days in which to build enough of a head from a cold start to deploy — the APM requires about 60 seconds. While a conventional steam engine needs roughly 25 crew members to operate, the APM needs just 11. Even better, the APM is heavily automated and features 32 control centres spread around the ship so that if one area or engine is damaged or destroyed, the crew can still get moving. And once the Makin Island reaches its destination and deploys its forces, the fuel-sipping electric motors allow it to “stay on station” for nearly twice as long as if it were steam-powered.
“Our Sailors and Marines successfully met every mission during our historical maiden deployment in support of the nation’s maritime strategy,” Capt. Cedric Pringle, Makin Island’s commanding officer said in a press statement. “As the Navy’s first operational test platform for this hybrid-electric propulsion system, our fuel efficiency directly enhanced the ability to operate forward for longer. Additionally, our significant fuel cost savings, coupled with our lessons learned, will serve as a solid foundation for optimising this ship, as well as current and future ship designs. The value of our first deployment will continue to increase, as we assess required refinements in engineering subsystems, training, and logistics support.”
While the Makin Island is the most advanced ship in her class, is but a preview of the new LHA-class of Amphibious Landing Ships that will eventually replace her. The cutting edge machinery control system, water mist fire protection systems, and advanced command and control systems aboard the Makin Island will likely find their way into the next fleet. The only problem the USS Making Island faces now is finding a port where it can plug in. [US Navy – Navysite – CNet – Wikipedia – Image: Northrop Grumman Shipbuilding, Gulf Coast]