All parts of the cargo lifting equipment must be rigorously and regularly checked with certificates issued attesting to the ‘safe working load’ – ‘swl‘ of each unit. These inspections can be carried out by Classification Societies or by certain other internationally recognised authorities specialising in this activity. Certainly, it is always best to ensure that a Charter Party contains confirmation by the Shipowner that a vessel’s gear certificates are up to date and will remain so during the currency of the voyage/timecharter involved. Failure to attend to this aspect could cause shore workers to refuse to handle a vessel or, worse, injury or death resulting from defective or uncertificated gear could render to those involved enormous financial penalties in certain areas of the world. The basic derrick can be extremely versatile and is capable of adaption for certain trades. ‘Union purchase‘ is a method of joining derrick booms to a particular rigging method, simple to use and fast in operation, so that loads can be moved speedily from shore to cargo hold, or vice versa. The problem with the system is that once the rigging is set up it has to be altered to adjust the places of lifting and setting down of each load. Thus cargo has to be moved to an exact position prior to lifting and taken away from another exact position at the end of each movement cycle. It is therefore a labour-intensive method (although this is not a problem in certain areas of the less-developed world). Additionally, however, the union of derricks in this way reduces the swl, so that two 5-tonne swl derricks might have a union purchase capacity of less than half the individual swl – say 2 tonnes. However, for bagged goods, this may well not be a problem, and the system has its advantages for the discharge of bagged goods in less-developed regions.