Tankers show the way forward
This Mitsubishi-built, MAN-designed, unit was the first large-bore 12-cylinder Diesel engine to be delivered
It was tankers that provided the headlines in the October 1961 issue of The Motor Ship. A glimpse of the future came from the fact that three separate contracts had been placed, all with Japanese builders, for large gas-carrying tankers.
All three were of 20,000gt or more, one purely for LPG and the others, one of which was a conversion job, carrying a combination of LPG and oil products.
However, it was the propulsion systems for tankers of more conventional type which proved most newsworthy. The magazines Comment column noted that the technology of the day meant that all but the largest tankers could now be powered by Diesel engines, and even larger engines could be expected in the future that could mean the steam turbine would be superseded.
The largest tanker engine to date was reviewed – a 12-cylinder turbocharged MAN KX84/160C unit built by Mitsubishi Heavy Industries, for the 73,000ton Olympus. Although two similar large-bore engines had been built, this was the first 12-cylinder example. The engine was rated for a continuous output of 22,000bhp at 115rpm, with bmep of 8.1kg/cm2 (7.94bar).
Another solution for the relatively high power requirements of a large tanker was adopted for the 34,050dwt tanker London Independence, whose two Gotaverken non-turbocharged 15,000bhp eight-cylinder diesels drove AC shaft generators and also provided waste heat for a further steam-turbine powered generating plant, providing all the ship’s electrical power and saving a substantial amount of fuel.
A similar principle was offered by Schleiker Werft of Hamburg for a 50,800dwt tanker design for Marlin of Liberia. This employed a twin-screw configuration, with four four-stroke engines - two pairs of SEMT Pielstick units with each pair driving a CP propeller. The arrangement of the engines was interesting: each pair, comprising one 16PCV and one 12PCV of 5,120bhp and 3,840bhp respectively, was mounted above the shaft, with the engines electro-magnetically coupled to a twin-input gearbox between each engine. Shaft generators, one per gearbox, supplied all of the ship’s electrical needs (a separate small Diesel genset was provided for harbour use).
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