Titanic's fourth funnel was mostly for show
The original plan for White Star's giant liners had three stacks. Designers added a fourth to improve their appearance, and on all three sisters it was a dummy that vented galley smoke and engine-room air rather than boiler exhaust. It gave Olympic, Titanic and Britannic a balanced silhouette, replacing the clutter of ventilation cowls found on rival ships.
The trio grew out of a commercial scare. In July 1907, two months before Cunard's Lusitania was due to sail, White Star chairman J. Bruce Ismay and Harland and Wolff director William Pirrie met at Pirrie's Belgravia home and worried over her record-breaking speed. White Star could not beat Cunard for pace, so Pirrie proposed winning on size and luxury instead. Alexander Carlisle and Thomas Andrews, Pirrie's nephew, drew up the designs, and the contract was signed in July 1908.
Olympic's keel went down in December 1908 and Titanic's in March 1909, the two built side by side after three slipways were cleared away and gantries over 200 feet high erected above them. Each was 269 metres long and displaced 52,310 long tons, with nine decks, seven of them for passengers. Three propellers drove them: reciprocating steam engines turned the outer pair and a turbine the centre, powered by 29 coal-fired boilers. Titanic was even given a three-bladed central propeller to compare against Olympic's four-bladed one.
Luck divided them sharply. Titanic sank on her maiden voyage after striking an iceberg. Britannic, never used as a passenger liner, was serving as a hospital ship when she hit a naval mine off Kea in the Aegean in November 1916. Olympic worked for 24 years before being scrapped in 1935.
The disaster reshaped the survivors. Originally only eight of fifteen watertight bulkheads reached D Deck; Olympic was refitted in 1913, and Britannic was designed with bulkheads extending higher. After the First World War, Olympic switched from coal to oil, cutting her engine crew from 350 to 60. She remained the largest British-built ship until Queen Mary arrived in 1936.
Source: Olympic-class ocean liner
