Defence Notes

Surface Navy: Hybrid propulsion chosen for cutters

13th January 2017 - 12:00 by Scott Gourley in Arlington, Virginia

DRS Technologies, a Leonardo Company, has been selected to provide the hybrid-electric drive propulsion system for the US Coast Guard Offshore Patrol Cutter.

The company received the order from Eastern Shipbuilding Group on 6 January.

Speaking at this week’s Surface Navy Association Annual Symposium, Clive Wilgress-Pipe, director of business development and strategic programs at DRS Power Technology said that different propulsion designs could be applied to various maritime platforms; from a pure electric design to militarized hybrid designs that add an electric motor to a gas turbine or diesel component.

According to Wilgress-Pipe, the pure electric design, ‘which is used a lot on cruise ships,’ might be appropriate for the emerging US Coast Guard Polar Icebreaker programme.

‘In hybrid designs, what a lot of navies are now doing with their frigates, is putting an electric motor on the shaft and still keeping the gas turbine, or possibly diesel engine,’ he said. ‘That way they can use the gas turbine for full power, “fight or flight,” either on its own or additive with the electric motor. Or they can use the electric motor only, if they are going for fuel savings. Or, more importantly for frigates these days, they can use the electric motor for submarine hunting.

'You couldn’t go full speed with that,’ he acknowledged. ‘Typically you rate it up to about 17 or 18 knots. But that’s all you need when you are doing submarine hunting.’ He noted that the shaft-mounted electric motor design is currently used on the Korean FFX-II frigate.

An alternative hybrid mounting option places the electric motor on the gearbox. Wilgress-Pipe said that the new Offshore Patrol Cutter design solution uses the gearbox mount configuration.