Some ships are highly specialised and able to carry only one particular commodity – others are flexible in design and able to transport a variety of cargoes. Modern designs of certain multi-deck vessels – originally conceived to carry general cargoes – are also capable of carrying a part or full cargo of containers or, perhaps, a bulk cargo, in addition to or instead of ‘break-bulk’ parcels of various commodities. If they are additionally equipped with a high capacity crane or derrick (termed a ‘heavy lift’) capable of safely lifting from shore to cargo hold and vice versa, an article weighing in excess of 100 tonnes, they have yet another facility of advantage to the vessel’s owners/operators. There are some vessels designed specifically with even heavier lifts in mind and one class uses two heavy lift cranes in combination to lift loads up to 640 tonnes at a time. Thus vessels with this cargo flexibility can intrude upon the specialised markets developed around the marine transportation of containers, bulk commodities and ‘heavy lift’ items, in addition to the carriage of bagged and baled goods. Certain bulkcarriers – outwardly the simplest design of dry cargo vessels – are adapted by their owners and/or builders to engage in specialist trades when an opportunity arises; for example, the carriage of lumber in cargo holds and on deck. Or the dimensions, design and fittings of the ship may permit trading to particular geographical regions -e.g. The Great Lakes, or to ice affected areas of the World. There are even vessels – ‘combination carriers’ – capable of engaging in both ‘wet’ markets and ‘dry’. These vessels (usually of 60,000 tonnes cargo capacity plus) are equipped to carry cargoes of crude-oil or dry-bulk commodities, such as ores, coal or grain.