Twistlocks There are many different designs of twistlock. Over 20 designs of manually operated twistlock are known to be in use together with at least 26 designs of semi-automatic twistlock. Semi-automatic twistlocks are twistlocks that lock automatically when they enter a corner casting or deck fitting but have to be released manually. They are sometimes just referred to as automatic twistlocks. Twistlocks are usually the property of the ship and it is possible that ports may find themselves having to work with types of twistlock with which they are unfamiliar.
More problems are likely to occur with semi-automatic twistlocks.
It is recommended that ports obtain information from shipping lines or agents on the methods of operation of semi-automatic twistlocks before a particular type has to be used for the first time. The information should include not only the normal method of use but also methods of freeing them if they jam. This can involve the use of simple special purpose hand tools or devices which may be carried by ships or made locally. Some of these devices may be screw operated. The information obtained should be used to develop trouble-shooting guidance for those who are likely to be involved.