The Tramp Steamer wri tten and illustrated by Ian Marshall or a period of roughly eighty yea rs, starting in about 1870, th e tramp steamer was far and away the mos t common type of ship in ocean-go ing trade. The tramp steamer was a modest-sized cargo vessel, steel built, with a single screw powered by ve rtical triple-expansion steam engines supplied from coal-fired boilers. The most common layout was the three-island type, which had high freeboard at fo'c'sle, central island, and poop, with interve ning well-decks fo re and aft, each penetrated by two hatches allowing access to the cargo holds. A central funnel was acco mpanied by a cluster of goosenecked ve nti larors, which provided fresh air to the boiler- and engine-rooms below. A navigating bridge straddled the fo re part of the central island, and the superstructure was occupied by officers' quarters and sometimes a few passenger cabins, together with the ship's lifeboats. The crews' quarters were usually in the fo'c'sle and sometimes in the poo p. M ost tramps had two masts, stepped centrally in the two well-decks, rigged with cargo-handling derricks. M any ships also carri ed sm aller, independent kingpost derricks mounted near the sides of the ship, fo re and aft. Som e had a fifth hatch between bridge and funn el allowing access to a central hold, which had its own derricks. A straight vertical stem, slab sides, and a graceful counter stern were hallmarks of its hull -form. Tramps had a nearly fl at bottom so as to have min imum draft, and the holds were as nearly as possible rectangular, for m aximum cargo capacity.
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Early steamships had fo llowed the pattern of sailing vessels in having a wea ther deck, which was also the main structural deck, running from stem to stern. Only small deckhouses were located above this level. In time they were succeeded by ships with raised deck areas at bow, amidships, and stern, whi ch afford ed better seawo rthiness, pro tected the ancho r gear, elevated engine-room skyli gh ts a nd ve ntil ato rs further fro m invading seas, and also gave som e protection to the steering gear. The layout of ca rgo space was much influenced by language in legislation for the levy of taxes (also dock dues and can al rolls), based on statu to ry m ethods of m eas urem ent o f ships and their ca rgo, and by the need to ensure safety a t sea. As a res ult, th ere was a p rog ressio n towards ships w ith a m o re extended upper deck amidships, a nd later m os t were built with an upper deck running the full length of the hull. Thi s was to acco mmodate low-density ca rgo in an area that was subj ect to lower assess ment than rhe holds; this deck ge nerally co ntained interruptio ns to p rov ide access to hatches in th e main stru ctural dec k below, a nd it was mos t often term ed the "sh el ter deck" o r "superstru ctu re deck." The space below the shelter deck was so m etimes referred to as '"twee n decks, " a nd in som e ships it was empl oyed to acco mm odate low-fare passe ngers, or "deck passe ngers." Tramps carried few passengers, however; ca rgo had first priori ty and the rime spent in port was likely to be prolonged,
D uncan Dock, Cap e Town (1951)
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HISTORY 129, WINTER 2009-IO