As ports have been enlarged, deepened, developed and, in the richer countries, equipped with relatively sophisticated cargo-handling equipment, so merchant ship naval architects have been required to incorporate general port needs into vessel design, and to plan yet larger vessels, capable of maximising earnings potential for their owners and of transporting goods worldwide at the lowest unit prices for the commodities involved. Commonly referred to nowadays as ‘multi-purpose‘ vessels, general-cargo ships fulfil the same functions as their predecessors hundreds of years ago – the ability to adapt to world trades and demands and to carry a variety of cargoes.These vessels were first mass-produced during World War II, when the famous 10,000 tons deadweight ‘Liberty’ type ships were built. Later, many of these vessels were sold to surviving and aspiring shipowners as the basis of modern post-war fleets, and their ‘three-island’ design (i.e. forecastle, midships-located bridge accommodation, and stern superstructure) remained in vogue until the 1960’s), when new designs – principally the British ‘SD14’ and the American designed but Japanese produced ‘Freedom’, as well as the German ‘Liberty Replacement’ (the GLR) – first appeared. There still remain a few elderly vessels at sea with bridge and engines located amidships, modern ships have aft-superstructure, bridge and engines, and with ‘cargo-friendly’, unobstructed hatchways and holds between these and the forecastle; and without the inconvenience of a ‘shaft-tunnel‘ covering a lengthy propeller shaft linking the ‘midships‘ main engine and the vessel’s propeller, being exposed to potential damage from poorly-operated ‘cargo-grabs’ when discharging a bulk cargo, or from heavy units of cargo (e.g. scrap metal) being carelessly loaded.