Confusing units in test certificates

摘要

As a port captain specialising in project cargoes, I regularly handle heavy lifts of 120-150 tonnes. Before starting the operations, I ask to see the test certificates for the lifting slings. On many occasions, only the test certificate for the original batch of wire rope used for making the sling is produced, without any document to show the sling's safe working load (SWL). This should be less than that of the parent wire rope, allowing forrnthe weaknesses introduced by the bending of the rope around the thimbles and splicing.