Complex sentence: The college was originally known as the Royal Naval College, Dartmouth, and as a Royal Naval shore establishment was later additionally known by the ship name HMS "Britannia" (there was a battleship called from 1904 to 1918).
Split into simpler sentences: The college was originally known as the Royal Naval College, Dartmouth. As a Royal Naval shore establishment, it was later known also by the ship name HMS "Britannia" (a battleship called operated from 1904 to 1918).