Bulk Barley

Vessels too wide to transit the Panama Canal are termed ‘cape-size‘ and usually this term is taken to mean vessels in excess of 100,000 tonnes deadweight, there being few bulkcarriers between 80,000 and 100,000 tonnes deadweight size. Bulkcarriers of between, say, 20,000 and 50,000 tonnes deadweight size are frequently loosely termed ‘handy-sized‘ whereas there is a specific class of bulkcarrier around 20,000/30,000 tonnes deadweight designed with measurements enabling transit of the St. Lawrence Seaway, and thus access to the Great Lakes system of North America, these maximum dimensions being . Bulkcarriers have a basically simple design, where superstructure, bridge and engines are located aft in nearly every case, leaving relatively unobstructed access to cargo hatchways. To avoid the expensive necessity of employing shore labour to ensure that bulk cargo safely fills extremities of the holds – i.e. it is safely ‘trimmed‘ – most bulkcarriers are constructed with ‘upper wing tanks‘, sometimes termed ‘topside tanks‘, providing ‘self-trimming‘ facilities on their underside. These upper wing tanks are used to carry ballast water when the vessel is empty at sea or only partly laden, other areas used for this purpose being tanks located forward and aft (‘fore-peak’ and ‘after-peak’ tanks) and, perhaps, a midships located ‘floodable-hold’, as discussed in the general-cargo vessel section. Because some bulk cargoes are relatively light (e.g. bulk barley) and thus a vessel’s hold can be filled before she comes down in the water to her permissible loadline marks, some ‘handy-sized’ bulkers utilise the space in these upper wing tanks for certain commodities (again bulk barley might be an example) that are relatively free-flowing. By loading through openings in the weatherdeck above the upper wing tanks, these spaces can be drained of ballast water at the loading port, washed through, cleaned and dried, the cargo then fed into the vacant spaces, thereby using otherwise wasted deadweight capacity.