The High Seas Fleet in October 1918 was built around the core of 18 battleships and 5 battlecruisers, most of which had been completed before the outbreak of war. Since the Battle of Jutland in May 1916, the obsolete pre-dreadnoughts had been de-commissioned, two new battleships with 15-inch guns ( and ) and the new battlecruiser had joined the fleet, but one dreadnought battleship had been damaged beyond repair by running aground in the Baltic. The fleet had undertaken only three major sorties at full strength into the North Sea since June 1916: 18–19 August 1916, 18-19 October 1916, and 22–25 April 1918. This prolonged period of relative inactivity, at a time when all other branches of Germany's armed forces were very heavily engaged, did much to undermine the morale of the crews and the self-respect of the officers. Acts tantamount to mutiny took place on various occasions during 1917, the most noteworthy being the arrest of 200 men from the battleship in August, resulting in two executions.