Combined diesel and diesel

Combined diesel and diesel (CODAD) is a propulsion system for ships using two diesel engines to power a single propeller shaft.

Combined diesel or gas (CODOG) Combined diesel and gas (CODAG) Combined diesel-electric and diesel (CODLAD) Combined diesel–electric and gas (CODLAG) Combined diesel and diesel (CODAD) Combined steam and gas (COSAG) Combined gas or gas (COGOG) Combined gas and gas (COGAG) Combined gas and steam (COGAS) Combined nuclear and steam propulsion (CONAS) Integrated electric propulsion (IEP or IFEP) A gearbox and clutches enable either of the engines or both of them together to drive the shaft.

Two advantages over simply using a single, larger diesel engine of the same total power output are that (1) diesel engines have somewhat better specific fuel consumption at 75% to 85% max output than they do at only 50% output, and (2) there is a weight and size advantage to using two higher-speed engines compared to a single lower-speed engine, even with the slightly larger gearbox system.

Passenger and Car Ferry Ships Containerships Coast Guard Offshore General-Purpose Cutters Coast Guard Offshore Security Patrol Cutters Coast Guard Multi-mission Cutters Coast Guard Interceptor Cutters Coast Guard Security Cutters Patrol Corvettes / Navy OPVs Corvettes Frigates LSDs (landing ships, dock) LPDs (landing platforms, dock) Amphibious Flat-topped Ships FACs (fast attack-craft) Cruise Ships