High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! HMHS Britannic was the third and largest Olympic-class ocean liner of the White Star Line. It was the sister ship of RMS Olympic and RMS Titanic, and was intended to enter service as a transatlantic passenger liner. She was launched just before the start of the First World War and was quickly put to use as a hospital ship. In that role she struck a mine off the Greek island of Kea on 21 November 1916, and sank with the loss of 30 lives.