Ship goes out of control, all because of a small switch.

In February 2023, a Panamanian-flagged oil tanker experienced a complete power outage while underway, forcing it to drop both anchors and become uncontrollable. The incident occurred near the Changtong ferry route, in a curved section of the Yangtze River's main channel with an angle of approximately 40 degrees. The surrounding traffic was heavy, making the situation extremely urgent. After more than two hours of emergency rescue efforts, the tanker was eventually escorted to a repair facility.

During the inspection, the PSCO (Portable Maritime Safety Administration) identified five safety deficiencies and one other safety hazard, providing reasonable rectification suggestions for all. The vessel was urged to immediately implement these corrective measures to ensure it was in a safe and seaworthy condition.

Cause of Loss of Control: 

During prolonged navigation, the vessel was affected by currents, causing it to pitch and roll. The cumulative effect of the vibrations caused the already malfunctioning carbon dioxide remote-controlled system release valve in the fire control station to break its critical state and suddenly open. This triggered the internal limit switch, causing the engine room's air and fuel remote-controlled shut-off, resulting in a complete power outage and loss of control.

The release control box is a crucial component of a carbon dioxide fire extinguishing system, used to release carbon dioxide gas from stored cylinders to the protected area. It primarily operates by controlling the opening of the carbon dioxide cylinder valve via a high-pressure cylinder within the control box. It is an essential fire-fighting device for ships.