Abnormal Tension to the Chain Cables Caused by Working on Electric Windlass

This paper is a part of the research for the causes of breaking of chain cables which recently occurred successively on the newly built small vessels equipped with welded chains operated by electric windlass. It was concluded by theoretical and experimental investigations that in weighing the anchor, if stopping of windlass were too late to avoid unexpected pull on the chain by force when driving at a high notch or even at a low notch with high speed electric motor, according to its characteristics, the accessive tension should act suddenly on the chain from the inertia force of revolving mass of the motor and the mechanical parts of the windlass. This tension could easily exceed the proof test load of the chain and the repetition of such abnormal pull would be able to cause the chain to break.