Combined diesel or gas

Combined marine propulsion
CODOG CODAG CODLAG CODAD COSAG COGOG COGAG COGAS CONAS

Principle of a CODOG arrangement

Combined diesel or gas (CODOG) is a type of propulsion system for ships that need a maximum speed that is considerably faster than their cruise speed, particularly warships like modern frigates or corvettes.

For every propeller shaft there is one diesel engine for cruising speed and one geared gas turbine for high speed dashes. Both are connected to the shaft with clutches, only one system is driving the ship in contrast to CODAG-systems, which can use the combined power output of both. The advantage of CODOG is a simpler gearing compared to CODAG but it needs more powerful (or more) gas turbines for the same maximum power output and also the fuel consumption at high speed is even worse compared to CODAG.

CODOG vessels

• MGB 2009, a prototype Motor Gun Boat of the Royal Navy (1947), and
• The Tribal class frigates (COSAG gas turbine propulsion. First ship commissioned in 1961
• The two German torpedo boats Pfeil and Strahl (Vosper class, 1963-65)
• The Swedish Spica class motor torpedo boats (First vessel commissioned in 1966)
• The US Coast Guard Hamilton class cutters (from 1967)
• Finnjet (the World's fastest passenger ferry)
• Queen Mary 2
• Halifax Class Frigates of the Royal Canadian Navy
• Bremen class frigates, and
• Brandenburg class frigates of the German Navy
• Anzac class frigates of the Royal Australian Navy (RAN) and Royal New Zealand Navy (RNZN)
• other MEKO type frigates or corvettes
• Peder Skram class frigate of the Royal Danish Navy
• Pohang class corvette of the South Korean Navy
• Visby class corvette of the Swedish Navy
• Shivalik class frigate of the Indian Navy
• Niterói class frigates of the Brazilian Navy
• BNS Bangabandhu of the Bangladesh Navy