Cranes

Naturally, when chartering general-cargo, multi-purpose ships, the location, safe working loads and capabilities of the vessel’s derricks may be of paramount importance, and the broker acting for a Charterer should ensure that he or she is entirely familiar with the requirements of his principal and can properly evaluate the ships proposed for the business with regard to their cargo gear potential. In a chartering sense, the term ‘double-rigged‘ means that two derricks serve each hatchway. Modern multi-purpose vessels are almost always equipped with cranes. These are usually electrically powered, having the advantage over most derricks of being more versatile and capable of accurately placing and picking up cargo from a variety of adjacent positions. Cranes are, however, more sophisticated and expensive to maintain, also requiring more efficient handling than derricks. Fewer cranes are needed than derricks, though, and they are self-contained in their own units, not requiring supporting samson posts, etc. Typical lifting capacities of shipborne cranes range from 5 to 40 tonnes swl, with most modern vessels tending towards the higher capacities, perhaps having the facility to unite the lifting capacity of two adjacent cranes, thereby substantially increasing the maximum capacity – e.g. 2 x 25 tonnes cranes equating to 1 x 50 tonnes. To recap, most newbuildings are fitted with cranes of around 25 to 60 tonnes swl, derricks still being used to provide a heavy-lift facility, where required.