General Purpose Frigate Low-Speed Electric Drive - When does it Make Sense?

Light Frigates (LFs), like many warships, will spend a reasonable amount of sea time at low speeds. By definition, the LF has to be capable yet affordable, a difficult balance to strike, but a dichotomy which has to be addressed particularly given the cost pressures our world’s navies are under. Whilst low engine loading at loiter speeds may lead to fuel inefficiency and increased maintenance burden, a purely mechanical Combined Diesel and Diesel (CODAD) propulsion system is attractive from a simplicity perspective. Hybrid propulsion architectures, using electrical machines as motors for low-speed operations, can be employed as a way to address this part of the operating profile. This paper explores to what degree a hybrid solution is appropriate for a LF through the consideration of a number of factors.