Small bores show big potential

While the running cost of high-speed engines is higher than with medium- and low-speed, the power density is more favourable. This is especially true when generating, where the higher speed of the engine allows a lighter and cheaper alternator to be used. So for those wanting a lightweight or compact supply of power, the high-speed diesel has advantages – and they have started to make their mark in unusual places.

One example is Botnica, the Finnyards-built icebreaker designed by the Finnish Maritime Administration which has six engine-generator-engine packages for main propulsion. The twelve Caterpillar 12V3512B electronic engines are coupled to each end of six ABB generators to produce 10MW of usable power. The power is fed to twin Azipods via ABB Megastar PWM controllers. This unusual installation is designed to cope with the wide variance in power requirements of this dual-purpose ship. During the winter it is deployed on icebreaking duties, and in the summer it is employed as a dynamically-positioned offshore exploration/drilling ship.