Boiler rooms

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Elevation drawing of boiler rooms 1 and 2 (343K GIF)
Plan drawing of boiler rooms 1 and 2 (362K GIF)
Section drawing of boiler rooms 1 and 2 (302K GIF)

A portion of the boiler shop, Harland & Wolff

From: The Shipbuilder, Vol. VI, Midsummer 1911, special number on The White Star Liners "Olympic" and "Titanic"

Altogther there are twenty-four double-ended and five single-ended boilers in each vessel, designed for a working pressure of 215 lb., which it is anticipated will be maintained under natural draught conditions.  The aftermost, or No. 1 boiler room contains the five single-ended boilers, boiler rooms 2, 3, 4 and 5 contain five double-ended, and the foremost, or No. 6 boiler room contains four double-ended boilers.  Owing to the great width of the ships, it was found possible to arrange five boilers abreast, as shown in [the section plan], except in No. 6 boiler room, where, owing to increased fineness, only four abreast could be fitted.

Each of the double-ended boilers is 15 ft. 9 in. diameter and 20 ft. long, and contains six furnaces; while the single-ended boilers, which are of the same diameter as the double-ended but are 11 ft. 9 in. long, contain three furnaces, so that the total number of furnaces is 159.  The latter are all of the Morison type, 3 ft. 9 in. inside diameter, and are provided with fronts of the Downie "boltless" pattern.  The firebars are of the Campbell type, supplied by Messrs.  Railton, Campbell & Crawford, of Liverpool.  The shells of the single-ended boilers are formed in one strake, the double-ended boilers having, as usual, three strakes.  All the shell plates are of mild steel 1-11/16. thick.

The arrangement of uptakes, by which the smoke and waste gases are conveyed to the funnels, is necessarily of a very elaborate nature, no less than twenty branches being required to one funnel in the case of boiler rooms 3 and 4. The branches from adjoining boiler rooms are united immediately above the watertight bulkhead separating the rooms, the bulkhead thus forming a valuable support to the uptakes and funnel above.  One set of uptakes is shown [below] and well illustrates their numerous ramifications.

Set of boiler exhaust uptakes

The four funnels have an elliptical cross section and measure 24 ft. 6 in. by 19 ft.  0 in.  Their average height above the level of the furnace bars is 150 ft.  A striking photograph of the last funnel of the Olympic leaving the shops is reproduced [below].

Last funnel of the "Olympic" leaving the Shops, Harland & Wolff

The arrangements in the Olympic and Titanic for loading and storing coal and feeding the coal to the stokeholds are the result of great experience. The bunkers consist of a 'tween deck space on each side of the ship between the lower and middle decks, into which the coal is first shipped and from thence distributed into the cross bunkers extending the full width of the vessel in each boiler room.  The stokers obtain the coal from doors in the cross bunker end bulkheads at the stokehold level immediately opposite the furnaces [see elevation drawing], an arrangement which reduces the amount of handling of the fuel for each boiler to a minimum.  A further advantage of the bunker arrangement is that no watertight doors are required in the bunker ends, as each set of boilers has the necessary coal supply provided in the same watertight compartment, the watertight bulkheads dividing the boiler rooms being placed at the centre of the cross bunkers.

Ash Hoists and Ejectors

The arrangements for discharging ashes on each of the two new White Star liners consists of ten See's ash ejectors, of which there are two in each large boiler room, placed as shown [in the plan drawing].  The ash ejectors are worked by the large duplex feed pumps, placed in a separate room adjoining each boiler room.  One of the See's ash ejectors is shown on the right-hand section [the elevation drawing].  The ashes are discharged by shovelling them into the hopper placed on the stokehold floor, whence they are drawn down by the rush of air to a water jet which is being discharged through the long inclined pipe shown, at a pressure of about 150 lb., the jet being maintained by the pump already referred to.  The water jet carries the ashes up the inclined pipe till, at the upper bend, they are deflected and discharged well clear of the ship's side.  In addition, there are four ash hoists supplied by Messrs.  Railton, Campbell and Crawford, for use when the vessel is in port.

Drawing of one of the ash hoists (130K GIF)

Ash hoists of this type have proved remarkably free from wear and tear and require a very small supply of steam, a 1/4-in. pipe only being used for the steam inlet. [The drawing] above shows clearly their arrangement and method of working.

Induced Draught and Fans

No forced draught is provided, it being the practice of the White Star Line to have forced ventilation only to the boiler rooms of their ships. For the latter purpose twelve Sirocco fans, two for each boiler room, have been supplied by Messrs.  Davidson & Co., of Belfast, fitted with Allen motors.  The fans are placed at the middle deck level and draw in air through ventilating shafts from the boat deck, supplying the same through trunks led down the bulkheads to the level of the furnaces.  Eight of them are 55 in. diameter, two 50 in., and two 40 in., a pair being illustrated [below].

Two of the stokehold electric fans

One of the stokehold fan controllers with the cover removed is shown in [below].

Stokehold fan controller, cover removed

It will be seen that the cables are fitted permanently into screw plugs, the holes for which are bored and tapped in the joint of the cover, so that they can be placed in position and the cover screwed down, making a simple and yet watertight joint.  The controllers can also be worked from the stokeholds by rods supported on ball thrusts.  The ball thrusts so greatly eliminate friction that the different positions on the controller can be easily felt below.

Steam and Exhaust Pipes and Valves

The steam supply is carried from the boilers to the engines by two main steam pipes made of welded steel, with a butt strap riveted over the weld, from which branches are carried to the various boilers, and which gradually increase in diameter as they approach the engine room forward bulkhead. On the forward side of this bulkhead, on each pipe line, is placed a balanced emergency stop valve (see [plan drawing]), which can be closed in a few seconds in case of need.  On the after side of the same bulkhead are the main stop valves, 211-in. diameter, each provided with a large separator and a cross connection, which allow either range of piping to be used for either or both engines.  The main stop valves are of the equilibrium double-beat type, and are operated by hand wheels and screws from the starting platform, which is situated in the centre of the reciprocating engine room.


The engine telegraphs for transmitting orders from the captain's bridge to the starting platform are of the usual type fitted in large vessels and call for no special comment. A system of illuminated telegraphs has been provided between the starting platform and the various boiler rooms to, enable the engineer on watch to communicate hos orders to each stokehold. With eleven stokeholds to control, the foremost of which is 320ft. from the, engine room, the necessity for such an arrangement is evident.  [The photo below] shows the transmitter and one of the receivers belonging to the installation, which has been supplied by Messrs. Evershed & Vignoles, Ltd., of London.

Boiler room telegraph (transmitter left, receiver right)

The same firm have also supplied a set of Kilroy's stoking indicators for each stokehold of which a regulator and one of the indicators are illustrated [below].

Kilroy's stoking indicator (firing rate regulator left, indicator right)

The regulator is set to the rate of firing desired by the engineer, and the indicators, which are electrically operated by current switched on from the ship's circuit, give visible and audible intimation to the fireman at the exact moment when each furnace is to be fired.  Five indicators are provided in each stokehold, one for each boiler, and are regulated so that the minimum number of furnace doors will be open at the same time, and no opposite doors in a double-ended boiler open togther.