Products & Services

Hybrid Shaft Generator

The Hybrid Shaft Generator (HSG) upgrade is a modification to the power electronics system which controls the shaft generator to switchboard power flow. This means that the diesel engine and the propeller can operate at variable speeds, whilst keeping the network frequency-stable and voltage fixed.

With the HSG system the switchboards see a constant voltage and frequency at variable engine rpm.

The HSG system upgrade allows for more flexible use of engine and propeller speed variations, so that both propeller and engine efficiencies can be maximised by ensuring that they are running at their most efficient point.


  • Reduced fuel consumption – Optimised system operation means that engine rpm can be reduced while maintaining the voltage and frequency to the switchboard. This results in considerable potential for fuel savings and NOx/CO2 reduction.
  • Flexible operations – with the Hybrid Shaft Generator upgrade, the shaft generator also acts as an electric motor. As a motor, it can operate alone, or together with the main engine for more power options.
  • Optimised propulsion mode selection – This system has a fast easy mode change capability between generating and motoring for five options: boost mode, diesel electric mode, parallel mode, transit mode and shore connection mode.
  • Longer engine life and reduced maintenance – reduced running hours on auxiliary gen sets, thrusters and electric motors extend their lives and maintenance intervals, lowering operating costs.
  • Increased comfort on board – Lower noise and vibration levels with reduced engine rpm and running hours.
  • System compatibility – Further additional fuel savings can be made when combined with a thruster starter upgrade.
  • Improved redundancy – the propulsion system still operates, even if one engine should fail.