Fuel cell submarines offer underwater stealth

For higher speeds, connection is made to the high-performance lead acid battery. An MTU 16 V- 396 diesel engine powers the generator for charging the battery installed on the lower of the two decks at the forward section of the submarine. The diesel generator plant is mounted on a swinging deck platform with double elastic mounts for noise and vibration isolation. The propeller motor is directly coupled to the seven-bladed screwback propeller.

U214

The U214 submarine, still in development, has a displacement of 1,700 tonnes, is 65 metres long and is manned by a crew of 27. The propulsion is again provided by a Siemens Permasyn engine which draws its power supply either from the fuel cells or from batteries which are fed by a diesel generator. Performance of the AIP system has been increased with two Siemens PEM fuel cells, which produce 120kW per module and will give the submarine an underwater endurance of two weeks.

EXPORT MARKETS

The HDW fuel-cell plants are being incorporated into all newly designed boats such as the U212 and U214 Class, but a fuel-cell plug-in section can also be integrated into an existing non-nuclear submarine during modernisation upgrades.

The German Navy has ordered four of the U212 submarines, with another two being built by Fincantieri for the Italian Navy. HDW is also developing the U214 fuel-cell submarine for export markets. The Greek Navy - the first foreign navy to order fuel cell submarines from HDW, in February 2000 - has ordered four Class U214 submarines. It was also the first foreign navy to order Class 209 submarines for export from HDW in 1967 and now possesses eight of these vessels. Three of these are scheduled to be refitted at Hellenic Shipyards with a fuel cell propulsion system. South Korea has also ordered three U214 submarines to enter service in 2007, 2008 and 2009 and to be built by Hyundai Heavy Industries.

The American Office of Naval Research (ONR) is also developing innovative propulsion systems based on new fuel-cell technology for efficient generation of electrical power—and greater design flexibility—for future ships.

ONR program officer Anthony Nickens explains that "the Navy's shipboard gas-turbine engines typically operate at 16 to 18 percent efficiency because Navy ships usually sail at low to medium speeds that don't require peak use of the power plant. The fuel cell system that ONR is developing will be capable of between 37 to 52 percent efficiency."

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