<Li> 23 knots (43 km / h; 26 mph) (maximum) </Li> <Tr> <Td> Capacity: </Td> <Td> 3309 wounded </Td> </Tr> <P> HMHS Britannic (/ brɪˈtænɪk /) was the final vessel built of the White Star Line's Olympic class of steamships, she was the fleet mate of both the RMS Olympic and the RMS Titanic and was intended to eventually enter service as the transatlantic passenger liner . </P> <P> Britannic was launched just before the start of the First World War . She was designed to be the safest and most luxurious of the three ships, drawing lessons from the sinking of the Titanic . She was laid up at her builders, Harland and Wolff, in Belfast for many months before being put to use as a hospital ship in 1915 . From 1915 to 1916, she served between the United Kingdom and the Dardanelles . She was shaken by an explosion, caused by a naval mine, off the Greek island of Kea on the morning of 21 November 1916, and sank 55 minutes later, killing 30 people . </P>

What was the name of the titanics sister ship