Hi Christopher!
Here is some information you may find useful about the Titanic's engines and boilers.
The engines for the "Olympic Class" liners were designed by a team of engineers under the direction of Rt. Honorable Alexander Carlisle and built at the Harland & Wolff foundry shop in Belfast, Ireland.
These ships, Olympic, Titanic and Britannic, were fitted with two sets of main reciprocating steam engines. Each engine was of the four crank triple expansion type. The primary cylinder of each engine was 4.4 feet in diameter; the intermediate cylinder 7ft in diameter and each of the two low-pressure cylinders were 8.1 feet in diameter with a stroke of 6.3 ft. The balance of valves and cylinders starting forward was:
Two slide valves with two ports and a common chest were operated by two connecting rods with a crosshead and single links to the low-pressure cylinder. These were connected to the high-pressure cylinder, which contained a single piston valve, two slide valves and immediate and low-pressure cylinder. Finally, there were two further slide valves at the aft end of the engine. All the valves were controlled and run by the Stevenson motion method.
Each of the main engines crank and thrust shafts were machined by hand at Harland & Wolff and were of 2.3 inches in diameter, the immediate shafts were 2ft 2.5 inches in diameter and the tail shaft was 2ft 4.5 inches in diameter. The crank and cross shafts each had a 9 inch diameter aperture, and the immediate and tail shaft was increased to 12 inches. The tail shafts were fitted on loose couplings so that they could easily be withdrawn for repair through the stern.
The two sets of engines each drove two steel boss shafts to which bronze wing propellers of 23.6 feet in diameter and when subjected to the 15,000 hp from each of the engines, would then rotate at a maximum speed of 75 rpm
The exhaust steam from the main engines was used to drive the Parsons turbine used to drive the central solid magnesium-bronze 16.6 foot diameter central propeller. The Parsons engine was designed to take the exhaust steam at 9psi then expand it down to 1lb absolute using a steam condensing plant. The condensing plant was operated at a vacuum pressure of 2 ft 4.5 inches on a barometric pressure of 30 inches. The turbine itself operated with circulating water between 55-60 degrees F. This turned a a turbine rotor 12 feet in diameter consisting of forged steel blades assembled in fans and mounted to a rotor shaft. The blades on this rotor were between 1.6 feet and 2.1 feet in length and were segmented. The length of the cast iron rotor casing from the first to last ring of blades was 13.8 feet. The turbine was unable to reverse, so the central propeller was not in use while the vessel was being maneuvered. A Unique feature of the Parsons turbines fitted on the Olympic Class is that the turbine could be operated with electric power when steam was unavailable. An electric lifting gear on its own power supply was provided for lifting the massive turbine cover for servicing and repair. The turbine rotor alone was weighed in at 130 tons with the entire assembly weighing 420 tons. The rotor shaft was unusually large at 1 ft 8.5 inches, which resulted in a center propeller shaft of 1 ft 10.5 inches. When powered by the 16,000hp turbine engine the center propeller had a maximum speed of 165rpm.
Here is a simplified five-step description of how the process works:
1. Steam from the boilers, at 215psi, enters the small high pressure (HP) cylinder, moving the piston in the cylinder.
2. The steam exits the HP cylinder, and is routed to the next cylinder along, the slightly larger intermediate pressure (IP) cylinder, moving the piston in the cylinder.
3. The steam exits the IP cylinder, and is routed to the next cylinder along, the much larger low pressure (LP) cylinder, moving the piston in the cylinder.
4. The steam, at 9psi was then passed to the Parsons turbine that powered the center propeller.
5. The steam exits the turbine and is then passed to the condensers, where it is cooled, turning it back to water, ready to be passed to the boilers, where the whole process starts all over again.
To provide the huge amount of steam needed to run the massive engines, each vessel was fitted out with 29 boilers forged and assembled by Harland & Wolff, 24 of which were double ended, at each end of each boiler were three Morrison furnaces for a total of 159 furnaces in all. The 24 double ended boilers were 15.9 feet in diameter and were 20 feet in length. The remaining five were single ended and were 11.9 feet in diameter.
Engine Stats:
Weight: 1,000 tons
Height: 30 feet
HP Cylinder Bore: 54 inches
IP Cylinder Bore: 84 inches
LP Cylinder Bore: 97 inches
Stroke: 75.6 inches
Horsepower: 15,000
I hope this helps with your question
Best Regards,
Brian
