CODAG differs from CODOG because the diesel engine continues to work when the gas turbine comes online. The added power suits a destroyer that needs economical range and a marked increase above cruising speed. A rocket-assisted-take-off analogy conveys the turbine's role as an extra burst beside the ship's everyday power source. The gearing becomes more complicated because both engine types must transmit power into the propulsion train. The word "and" therefore carries a clear trade-off between performance and mechanical complexity.
Notable Point · 21:26-22:44
How CODAG adds gas-turbine dash power
CODAG keeps economical diesel machinery running while a gas turbine adds power for a longer, faster burst, at the cost of more complicated gearing.