Four years ago, a large freighter was on a typical voyage when the captain and crew discovered the ship could not be steered. It couldn’t even move in a straight line. Instead it turned in circles over the open ocean. It was a ship owner and crew’s worse nightmare, as the ship with a dead weight of almost 40,000 ton followed its own path.
The container vessel was eventually towed to the nearest port and various causes were investigated, including the meter-diameter rudder bushing, which was found to be at fault. The bushing had been replaced three months earlier and, despite the specification being for Vesconite, a dimensionally-stable polymer suitable for underwater applications, a moisture-absorbing nylon rudder bushing was installed instead.