What does "Locked Shaft" refer to in ship operations?

"Locked Shaft" refers to a condition in ship operations where the shaft is immobilized and cannot turn at all. This scenario typically occurs due to a mechanical failure or an issue with the propulsion system, which could be caused by various problems such as a gear failure, loss of lubrication, or an obstruction. When a shaft is locked, it can create significant operational challenges for the vessel, as it directly affects the ship’s ability to maneuver or generate any propulsion power. Understanding this term is crucial for maintaining safe and effective ship operations, as it signals a need for immediate attention to avoid further damage or safety hazards.