Combined steam and gas (COSAG) is a

propulsion Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived from ...

system for

ship A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...

s using a combination of

steam turbine A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Par ...

s and

gas turbine A gas turbine or gas turbine engine is a type of Internal combustion engine#Continuous combustion, continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas gene ...

s to power the shafts.

System

gearbox A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (who founded Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/r ...

and

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

es enable either of the engines or both of them together to drive the shaft.Friedman, p. 206 It has the advantage of the cruising efficiency and reliability of steam and the rapid acceleration and start-up time of gas. This system was mainly used on first-generation gas-turbine ships such as the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

's and .

Citations

Bibliography

*{{cite book , editor1-last=Gardiner , editor1-first=Robert , editor2-last=Friedman , editor2-first=Norman , title=Navies in the Nuclear Age , date=1993 , publisher=Conway Maritime Press , location=London , isbn=1-55750-613-2, author-link=Norman Friedman, name-list-style=amp, chapter=Propulsion, last1=Friedman, first1=Norman, pages=199–210 Marine propulsion Steam power