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.

Principle of a CODOG arrangement

System

edit
Combined
marine
propulsion

CODOG
CODAG
CODLAD
CODLAG
CODAD
COSAG
COGOG
COGAG
COGAS
CONAS
IEP or IFEP

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 combined diesel and gas (CODAG) systems that can use the combined power output of both.[1] The advantage of CODOG is a simpler gearing compared to CODAG, but it needs either more powerful or additional gas turbines to achieve the same maximum power output. The disadvantage of CODOG is that the fuel consumption at high speed is poor compared to CODAG.

CODOG vessels

edit

Citations

edit
  1. ^ Friedman, p. 206

Bibliography

edit
  • Friedman, Norman (1993). "Propulsion". In Gardiner, Robert & Friedman, Norman (eds.). Navies in the Nuclear Age. London: Conway Maritime Press. pp. 199–210. ISBN 1-55750-613-2.