Olympic, the first of the class of ships, was the only one not to come to a 'sticky' end, although she was badly damaged in a collision with the cruiser Hawke.
Laid down: 16th December 1908
Launched: 20th October 1910
Maiden voyage: 14th June 1911
No naming ceremony - same as for the other two ships, despite what some films may show. White Star Line policy.
Olympic was successful and sailed for 24 years until being scrapped in 1935. She was nicknamed "Old Reliable".
Britannic did not see service as a passenger ship, being converted into a hospital ship for the First World War. The largest of the three ships, having been modified following the sinking of Titanic.
Laid down: 30th November 1911
Launched: 26th February 1914
Sunk: 21st November 1916, off Kea Island, Greece, probably by a mine. 30 lives lost.
Titanic
Laid down: 31st March 1909
Launched: 31st May 1911
Maiden voyage: 10th April 1912
Sunk: 15th April 1912 (2.20a.m.)
As you will see, none of the ships actually took three years to build, although fitting out was delayed in some cases.