Combined gas and gas

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Principle of a COGAG propulsion system COGAG-diagram.png
Principle of a COGAG propulsion system

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]

Contents

Description

Combined marine propulsion

Combined diesel or gas (CODOG)
Combined diesel and gas (CODAG)
Combined diesel-electric and diesel (CODLAD)
Combined diesel–electric and gas (CODLAG)
Combined diesel and diesel (CODAD)
Combined steam and gas (COSAG)
Combined gas or gas (COGOG)
Combined gas and gas (COGAG)
Combined gas and steam (COGAS)
Combined nuclear and steam propulsion (CONAS)
Integrated electric propulsion (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

References