Combined gas and gas

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Principle of a COGAG propulsion system

Combined gas turbine and gas turbine (COGAG) is a type of propulsion system for ships using two

gearbox and clutches allow either of the turbines to drive the shaft or both of them combined. Marine usage of COGAG systems are similar to those found ashore.[1]

Description

Combined
marine
propulsion

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

A COGAG system consists of two gas turbines, each connected to a reduction gearbox. These are each attached to a coupling with both connected to larger gearbox and then to the ship's propeller.[2]

Advantages and disadvantages

Advantages of the system include a large degree of automation along with quick startup time, they are easier to silence and protect from shock.[3] Compared to combined diesel and gas (CODAG) or combined diesel or gas (CODOG), COGAG systems have a smaller footprint but a much lower fuel efficiency at cruise speed and for CODAG systems it is also somewhat lower for high speed dashes.[4] Issues with COGAG systems include their complexity and gearbox issues and high fuel use.[5]

List of COGAG ships

Citations

  1. ^ Soares 2015, pp. 10, 27.
  2. ^ Plaff 2021, p. 95.
  3. ^ Graves & Carleton 1963, p. 12.
  4. ^ Soares 2015, p. 31.
  5. ^ Plaff 2021, p. 92.

References

  • Graves, G. L.; Carleton, R. S. (September 1963). "Gas Turbines for Unconventional Craft". Bureau of Ships Journal. 12 (9): 7–12.
  • Plaff, Manfred (2021). Ship Operation Technology: Reference Book and Guidebook. Wiesbaden, Germany: Springer Fachmedien. .
  • Soares, Claire (2015) [2008]. Gas Turbines: A Handbook of Air, Land and Sea Applications (Second ed.). Kidlington, Oxford: Elsevier. .