history narrowed space available.
Firing all these hungry furnaces was a challenge and the designers did their best to ease fuel handling and avoid coal heaps on the boiler room plates. The main coal bunkers were in a tweendeck space on each side of the ship between the lower and middle decks of the machinery space, from where the coal was hand trimmed to cross bunkers extending right across the full width of each boiler room. Stokers took their coal from doors in the cross bunkers immediately opposite the furnaces. Watertight doors between each boiler room were placed at the centre of the cross bunkers. The 24 double-ended boilers
called
for 48 firemen, 20 trimmers and five leading firemen to be on duty for each four-hour watch; and each boiler room required four trimmers to cart the coal and carry ash to the ejectors. One fireman was responsible for working one end of a double-ended boiler, while leading firemen supervised the boiler room crew. Firing the boilers was to a schedule regulated by a Kilroy’s Stoking Regulator in conjunction with Kilroy’s Stoking Indicator for each boiler. These devices, via indicators and gongs, gave the signal for the firemen of the exact moment that each furnace was to be fired; the regulator could be set for firing the furnaces every eight, nine, 10, 12, 15, 20, 25 or 30 minutes, depending on how much steam was needed and the number of boilers on line at any time.
The instruments were so configured that
the minimum number of furnace doors were open at the same time, and no two opposite doors in a double-ended furnace would be open at the same time. The intervals between firing could be set by the duty engineer. Handling the ashes might seem to be
and raking of furnaces.
Some 29 coal-fired Scotch boilers with a total of 159 furnaces were installed to raise steam, arranged five abreast in five boiler rooms and four abreast in the forward room
a major problem but the arrangements on Olympic and Titanic were quite simple and effective. The firemen shovelled the ashes into a hopper placed on the stokehold floor, from where they were sucked to a water jet which carried the ashes well clear of the ship’s side. As well as the 10 See’s ash ejector pumps fitted, four hoists were provided for port use, by which bagged ashes were lifted to upper deck discharge points. Firemen who served on Olympic described
the work as good and not at all like earlier coal-burners, where coal was everywhere in the stokeholds and intense heat contributed to the traditional ‘hell-hole’ image. Their key task was to keep the furnaces full at regular intervals, and there was not too much slicing
Conditions were further improved by the White Star Line policy of forced ventilation of the stokeholds and no forced draught of the boilers. With the average height of the four 24½-ft (7.5m) major axis diameter funnels some 150ft (45.7m) above the firebars, however, natural draught was hardly a problem. The superlative dimensions of the main engines and boilers were mirrored by some of the auxiliary plant. Many ship designers of the period did not devote much importance and hence space to electricity generating machinery but the two superliners were in a league of their own in lighting demands alone. A separate machinery space – described as palatial – housed the four large steam-powered generator engines, which were of the W H Allen totally-enclosed compound type. Each engine, comprising an HP cylinder (17-inch/43.2cm bore) and two LP cylinders (20-inch/50.8cm bores) with 13-inch (33cm) strokes, was directly coupled to a compound-wound 400kW DC dynamo also manufactured by W H Allen. Steam was supplied at 185 lb/in2 and at a maximum speed of 325 rpm the auxiliary engines could each develop 580 ihp. Large steam reciprocating engines were chosen for electrical power generation rather than turbines because of the exhaust steam being used for boiler feed water heating (turbines would have needed to exhaust into a condenser if their economy of operation was not to be seriously undermined). Power was generated at 100V with a full load plant capacity of around 20,000A.
In addition, two 30kW steam-driven gensets were mounted on the saloon deck level way above the waterline: these were running until Titanic sank, the doomed liner reportedly going under with ‘all lights blazing’. Steam engines of a similar size to the main genset machines were also used to drive the main circulating
pumps.
Two
separate centrifugal pumpsets, each driven by a 13-inch (33cm) and 22½-inch (57.4cm) bore/15-inch (38.1cm) stroke two-cylinder compound engine, were installed on each side of the turbine engineroom. These delivered huge quantities of sea water to the two main pear-shaped condensers in the same room which were designed to operate at 28½-inches (72.6cm) of vacuum. Also arranged in the turbine room were
On the Titanic large steam reciprocating engines provided electrical power generation 18 I Marine Propulsion I February/March 2012
the Weir Duplex-type main air pumps, four in all, incorporating air and water cylinders of 36-inch (91.4cm) diameter and 21-inch (53.3cm) stroke. MP
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