The Rolls-Royce Marine Spey is a marine gas turbine based on the Rolls-Royce Spey and TF41 aircraft turbofan engines. The Marine Spey currently powers seven ship classes including the Royal Navy's Type 23 frigates and provides a power output of 19.5 MW (about 26,150HP). The Marine Spey incorporates technology from the Tay and RB211.