Combined Diesel and LM2500 Gas Turbine Propulsion Enhances Corvette/Frigate Missions

The LM2500 Gas Turbine is used for propulsion of naval ships from 220 tons to 14,000 tons displacement. Those ships from 220 to 4000 tons have used combined diesel or gas turbine (CODOG) systems in all but one ship class. Destroyers and larger ships, 7000 tons and up, have all used solely LM2500 turbines as Combined Gas Turbine and Gas Turbine (COGAG). Recently, the diesel engine industry has announced the advent of technological developments whereby diesel engine specific power can be significantly increased. Thus it is being suggested that with this new technology, all diesel propulsion (CODAD) can replace various propulsion systems currently using combined diesels with gas turbines. This paper explores the desired mission objectives for corvette/frigate class ships and develops an analytical comparison of all diesel and combined propulsion abilities to satisfy the ship’s missions. The comparison assesses the system’s relative impact upon propulsion system acquisition and life operating cost, system operational flexibility, ship’s detectability, and overall ability of the ship to perform the broadest range of mission requirements.