The Arethusa-class cruisers were a class of eight oil-fired light cruisers of the Royal Navy all ordered in September 1912, primarily for service in the North Sea. They had three funnels with the middle one somewhat larger in diameter than the others. All served in World War I. They were designed as follow on to the earlier scout cruisers, to operate with destroyers in the North Sea but incorporated improvements on the previous ships. They retained the side protection introduced in the later ships of the previous Town class, but reverted to a mixed main armament that was a feature of earlier ships. The ships of the class underwent modification during the war, receiving an additional pair of torpedo tubes and an upgraded anti aircraft armament, whilst all but HMS Undaunted were fitted to la