The early Deltic engines designed for the Admiralty were expensive to produce and it soon was recognised that if D Napier & Son were to have any commercial sales the engines would have to be “of cheapened construction”. The Deltic was designed for use in different scenarios and able to be fitted with a forward / reverse gearbox or flange mounted generator. As far as possible components were standardised meaning that, for example, a machined hole might not actually be used in that particular engine. This meant that an additional plug or cap would have to be manufactured and fitted at extra cost with no real benefit. As such a Deltic Design Study Group was formed to find methods to simplify engine manufacture whilst hopefully improving engine functional operation.
As such a new Deltic standard (DS102) was created which not only made it cheaper to produce but improved the design. Externally the change was immediately apparent but the considerable reduction of studs attaching the crankcase cover to the engine. More importantly the cylinder block had been redesigned reducing the cost of the raw casting by 25% and also reducing the machining and other manufacturing costs. The new design also featured an improved circuit for the engine coolant which ensured flow rates to individual cylinders were equalised. The net result was that the engine manufacture cost was almost halved from £30,000 to £16,000. Taking inflation from 1955 to today into account, in today’s terms this is a reduction of £310,000 from around £660,000 to £350,000!
The first Series 2 Deltic engines were fitted into a bulk iron ore carrier named Bahama King. The trial was not a success due to the cargo acting a a grinding paste on engine components! However the Deltic engine saw early commercial sales in applications as diverse as fast passenger ferries (Shell for Lake Maracaibo), luxury yacht (Naief for the Sheik of Qatar) and rail traction (9 and 18-cylinder engines for British Railways).
