GE’s Power Conversion business has increased its offshore systems portfolio with Inovelis, a podded thruster with unmatched fuel efficiency and overall performance. The company said the move could change the way the maritime industry views propulsion technology.

Inovelis incorporates an electrically powered propeller with its motor housed within a steerable pod mounted beneath the hull of an offshore vessel. It incorporates all the assets of a podded thruster, including maneuverability, responsiveness and excellent fuel economy. Based on pump jet principles, it features fixed stator vanes and a nozzle that act together to guide the water flow across the impeller blades, substantially enhancing propulsion efficiency. Its compactness enables an even greater degree of integration between the hull and the propulsion unit, further influencing the ships’ fuel economy and emissions.

Pump jet technology was originally used in submarines, and is already used for high-speed surface vessels. Now GE is applying it to offshore platform support vessels (PSVs). The Inovelis solution has higher thrust capability than a more conventional propulsion system, as well as improved hydrodynamics, providing higher efficiency over a wider range of operations, in dynamic positioning (DP) and in transit. A traditional propulsion set-up for a PSV has a large propeller with a nozzle, which has reduced performance when the speed of the ship increases.

Whereas a vessel with a traditional propulsion system has a propeller pushing on the water, a pump jet draws in water and then forcibly ejects it out through a nozzle. It is the marine equivalent of a jet engine, except that while jet engines are fixed, Inovelis can be pointed in any direction on a horizontal plane.  Paul English, marine leader, GE Power Conversion, stresses that Inovelis is a new concept that brings better performance – both improved thrust capability as well as improved hydrodynamics. The combination maximises performance of pod technology and brings fuel efficiency.

He cites a PSV driven by two 2.5 MW Inovelis pods, operating 30 per cent of the time in transit at full speed. “The benefit in terms of fuel savings could be, based on our estimates, up to $250,000 in one year,” English says.

“There is a clear trend towards larger, more capable offshore support vessels and a second trend towards the search for oil and gas taking these vessels ever further from home ports. Ship operators are looking for systems that support cost-effective, fuel efficient, rapid transit without sacrificing the capability to operate effectively and efficiently once on site in DP mode. This raises a dilemma as many current designs are a compromise between these two differing requirements.”

English says that the Inovelis advantage is so significant that it has the potential to permit ship designers to incorporate reduced capacity power plant – fewer cylinders or smaller engines - when designing offshore vessels.