Single- and double-acting cylinders

These often transmitted their force through the beam by means of chains and an "arch head", as only a tension in one direction was needed.

The main impetus towards double-acting cylinders came when James Watt was trying to develop a rotative beam engine, that could be used to drive machinery via an output shaft.

This was for similar reasons to the internal combustion engine, as avoiding the piston rod and its seals allowed a more effective crankcase lubrication system.

This, in turn, has the advantage of allowing easy access to the bottom of the piston for lubricating oil, which also has an important cooling function.

Small petrol two-stroke engines, such as for motorcycles, use crankcase compression rather than a separate supercharger or scavenge blower.

This was for two reasons: as for the high-speed steam engine, the high force on each piston and its connecting rod was so great that it placed large demands upon the bearings.

A single-acting piston, where the direction of the forces was consistently compressive along the connecting rod, allowed for tighter bearing clearances.

Lenoir's steam engine-derived cylinder was inadequate for the petrol engine and so a new design, based around poppet valves and a single-acting trunk piston appeared instead.

In 1935 the US submarine USS Pompano was ordered as part of the Perch class[iii] Six boats were built, with three different diesel engine designs from different makers.

[5] Owing to the limited space available within the submarines, either opposed-piston, or, in this case, double-acting engines were favoured for being more compact.

Pompano's engines were a complete failure and were wrecked during trials before even leaving the Mare Island Navy Yard.