An engine (110, 210) for moving a conveyance (132) through a fluid includes first and second pressure creating means (13, 14) for pressurising an engine airflow, and intercooling means (116, 290, 292) for cooling the engine airflow between the first and second pressure creating means (13, 14). The intercooling means (116, 290, 292) includes a heat exchanger (116) which is arranged to be cooled by a flow of the fluid generated by the relative movement of the conveyance (132) through the fluid.