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The Machinery of the Titanic - 1912

From the Congressional hearings, the description of the machinery provides information on the reciprocating engines, turbine, boilers, auxiliary and main steam pipes, condensing plant and pumps, bilge and ballast pumps, and other essential machinery, presented for non-engineers.

22-Ton Turbine Propellor on the RMS Titanic

22-Ton Turbine Propellor on the RMS Titanic. The Universal Engineer (December 1911) p. 412. GGA Image ID # 104ff0403b

The propelling machinery was of the combination type, having two sets of reciprocating engines driving the wing propellers and a low-pressure turbine working the center propeller.

Steam was supplied by 24 double-ended boilers and 5 single-ended boilers, arranged for a working pressure of 215 pounds per square inch.

The turbine was placed in a separate compartment aft of the reciprocating-engine room and divided from it by a water-tight bulkhead.

Boilers on the RMS Titanic

Boilers on the RMS Titanic. The Truth About the Titanic (1913) p. 52. GGA Image iD # 1055386319

The main condensers, with their circulating pumps and air pumps, were placed in the turbine room. The boilers were arranged in six water-tight compartments, the single-ended boilers being placed in the one nearest the main engines, the whole being built under board of trade survey for passenger certificate.

Reciprocating Engines

View of the Starboard Reciprocating Engines on the RMS Titanic.

View of the Starboard Reciprocating Engines on the RMS Titanic. It may be stated that both triple screw steamers Titanic and Olympic have propelling plants consisting of reciprocating engines and a low-pressure steam turbine. The two sets of reciprocating engines, one driving each wing shaft are of the four crank triple type and are arranged to work at 215 pounds per square inch and to exhaust at 9 pounds absolute. The International Steam Engineer (November 1911) p. 744. GGA Image ID # 1055751ec4

The reciprocating engines were of the four-crank triple-expansion type. Each set had four inverted, direct acting cylinders, the high-pressure having a diameter of 54 inches, the intermediate pressure of 84 inches, and each of the two low-pressure cylinders of 97 inches, all with a stroke of 6 feet 3 inches.

The valves of the high-pressure and intermediate cylinders were of the piston type, and the low-pressure cylinder had double-ported slide valves, fitted with Stephenson link motion. Each engine was reversed by a Brown type of direct-acting steam and hydraulic engine.

There was also a separate steam-driven high-pressure pump fitted for operating either or both of the reversing engines. This alternative arrangement was a stand-by in case of breakdown of the steam pipes to these engines.


The low-pressure turbine was of the Parsons reaction type, direct coupled to the center line of shafting and arranged for driving in the ahead direction only. It exhausted to the two condensers, placed one on each side of it. A shut-off valve was fitted in each of the eduction pipes leading to the condensers.

An emergency governor was fitted and arranged to shut off steam to the turbine and simultaneously change over the exhaust from the reciprocating engines to the condensers, should the speed of the turbine become excessive through the breaking of a shaft or other accident.


All the boilers were 15 feet 9 inches in diameter, the 24 double-ended boilers being 20 feet long, and the single-ended 11 feet 9 inches long. Each double-ended boiler had six and each single-ended boiler three furnaces, with a total heating surface of 144,142 square feet and a grate surface of 3,460 square feet.

The boilers were constructed in accordance with the rules of the board of trade for a working pressure of 215 pounds per square inch. They were arranged for working under natural draft, assisted by fans, which blew air into the open stokehold.

Auxiliary Steam Pipes

The five single-ended boilers and those in boiler rooms Nos. 2 and 4 had separate steam connections to the pipe supplying steam for working the auxiliary machinery, and the five single-ended boilers and the two port boilers in boiler room No. 2 had separate steam connections to the pipe supplying steam for working the electric-light engines.

A cross connection was also made between the main and auxiliary pipes in the reciprocating-engine room, so that the auxiliaries could be worked from any boiler in the ship. Steam pipes also were led separately from three of the boiler rooms (Nos. 2, 3, 5) above the water-tight bulkheads and along the working passage to the emergency electric-light engines placed above the load line in the turbine room. Pipes were also led from this steam supply to the pumps in the engine room, which were connected to the bilges throughout the ship.

Main Steam Pipes

There were two main lines of steam pipes led to the engine room, with shut-off valves at three of the bulkheads. Besides the shut-off valves at the engine-room bulkhead, a quick acting emergency valve was fitted on each main steam pipe, so that the steam could at once be shut off in case of rupture of the main pipe.

Condensing Plant and Pumps

There were two main condensers, having a combined cooling surface of 50,550 square feet, designed to work under a vacuum of 28 inches with cooling water at 60° F.

The condensers were pear shaped in section and built of mild steel plates. Four gun-metal centrifugal pumps were fitted for circulating water through the condensers. Each pump had suction and discharge pipes of 29-inch bore, and was driven by a compound engine.

Besides the main sea suctions, two of the pumps had direct bilge suctions from the turbine room and the other two from the reciprocating-engine room. The bilge suctions were 18 inches diameter. Four of Weir's "Dual" air pumps were fitted, two to each condenser, and discharged to two feed tanks placed in the turbine engine room.

Bilge and Ballast Pumps

The ship was also fitted with the following pumps : Five ballast and bilge pumps, each capable of discharging 250 tons of water per hour; three bilge pumps, each of 150 tons per hour capacity.

One ash ejector was placed in each of the large boiler compartments to work the ash ejectors, and to circulate or feed the boilers as required. This pump was also connected to the bilges, except in the case of three of the boiler rooms, where three of the ballast and bilge pumps were placed.

The pumps in each case had direct bilge suctions as well as a connection to the main bilge pipe, so that each boiler room might be independent. The remainder of the auxiliary pumps were placed in the reciprocating and turbine engine rooms.

Two ballast pumps were placed in the reciprocating-engine room, with large suctions from the bilges direct and from the bilge main. Two bilge pumps were also arranged to draw from bilges. One bilge pump was placed in the turbine room and one of the hot salt-water pumps had a connection from the bilge main pipe for use in emergency.

A 10-inch main ballast pipe was carried fore and aft through the ship with separate connections to each tank, and with filling pipes from the sea connected at intervals for trimming purposes. The five ballast pumps were arranged to draw from this pipe. A double line of bilge main pipe was fitted forward of No. 5 boiler room and aft of No. 1.


Funnels of the RMS Titanic, One Installed, One on a Rail Car

Funnels of the RMS Titanic, One Installed, One on a Rail Car. The Universal Engineer (December 1911) p. 418. GGA Image ID # 10502e45f1

There were four elliptical-shaped funnels; the three forward ones took the waste gases from the boiler furnaces, and the after one was placed over the turbine hatch and was used as a ventilator. The galley funnels were led up this funnel. The uptakes by which the waste gases were conveyed to the funnels were united immediately above the water-tight bulkhead which separated the boiler rooms.

All overhead discharge from the circulating pumps, ballast pumps, bilge pumps, etc., were below the deep load line, but above the light line.

The boilers were supported in built steel cradles and were stayed to the ship's side and to each other athwart ships by strong steel stays. Built steel chocks were also fitted to prevent movement fore and aft.  Silent blow-offs from the main steam pipes were connected direct to both condensers.

Congressional Serial Set 1912 – Loss of the steamship “Titanic” Presented by Mr. Smith of Michigan  - August 20, 1912 -  p. 574.

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