Gas turbines and generator systems for yachts
by Dag Pike
The Aga Khan’s gas-powered yachts
While the 118 was a complex installation, but even more complex was a yacht built under considerable secrecy at Devonport Dockyard. Reportedly built for HH the Aga Khan, this 42m yacht was powered by no fewer than six gas turbines coupled in pairs to three water jets. The smaller turbines were thought to be Eurodyne units, each producing about 3,000hp.
The smaller turbines were for relatively low speed cruising and harbour manoeuvring. When high performance was required, the second batch of turbines – each delivering around 10,000hp – could be coupled in. The yacht was designed for speeds of up to 80 knots, and the result was one of the most complex machinery installations ever. She was plagued by considerable delays mainly caused by the machinery and its final speed potential has never been revealed.
When high performance was required, HH the Aga Khan’s yacht could use a second batch of turbines – each delivering around 10,000hp
HH the Aga Khan was no stranger to high performance, with his involvement in the Destriero project, a 67m vessel built to challenge for the trans-Atlantic record. Powered by three General Electric LM1600 gas turbines, she had around 52,000hp on the throttles and averaged 53 knots across the Atlantic, burning fuel at the rate of 10 tonnes per hour.
On board the 86m Estasea, built for Roman Abramovich, there was one General Electric LM2500 gas turbine. This turbine produced around 30,000hp and was supplemented by four MTU diesels totalling over 12,000hp.
The diesels allow a variety of flexible cruising speeds and when the turbine is coupled in the speed could reach 28 knots – fast for a superyacht of this size – although the fuel consumption obviously shoots up resulting in a drastically reduced range.
Gas turbines are at the exotic end of the fast motor yacht market, but they continue to attract attention from owners and builders who want a vessel that will stand out from the crowd. When money is no object, the gas turbine can still be an attractive power source for propulsion systems.
However, the possibility of using gas turbines to power a superyacht’s other electrical systems is now being explored.