| Combined marine propulsion |
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CODOG |
Combined gas turbine and gas turbine (COGAG) is a type of propulsion system for ships using two gas turbines connected to a single propeller shaft. A 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
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
- Kolkata-class guided-missile destroyer (Indian Navy)
- INS Vikrant (aircraft carrier) (Indian Navy)
- Type 22 frigate (Batch 3) (Royal Navy)
- Invincible-class aircraft carrier (Royal Navy)
- Cavour-class aircraft carrier (Italian Navy)
- Asagiri-class destroyer (Japan Maritime Self-Defense Force), and subsequent destroyer classes
- Hyūga-class helicopter destroyer (Japan Maritime Self-Defense Force), helicopter carrier
- Izumo-class helicopter destroyer (Japan Maritime Self-Defense Force), helicopter carrier
- Type 055 destroyer (People's Liberation Army Navy)
- Neustrashimy-class frigate (Russian Navy)
- Sejong the Great-class destroyer (Republic of Korea Navy)
- Skjold-class corvette (Royal Norwegian Navy)
- Arleigh Burke-class destroyer (United States Navy)
- Ticonderoga-class cruiser (United States Navy)
- Wasp-class amphibious assault ship (United States Navy)
Citations
- ↑ Soares 2015, pp. 10, 27.
- ↑ Plaff 2021, p. 95.
- ↑ Graves & Carleton 1963, p. 12.
- ↑ Soares 2015, p. 31.
- ↑ 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. ISBN 978-3-658-32729-3.
- Soares, Claire (2015) [2008]. Gas Turbines: A Handbook of Air, Land and Sea Applications (Second ed.). Kidlington, Oxford: Elsevier. ISBN 978-0-12-410461-7.