War produces a lot of incidents of a note-worthy kind, but work in submarines produces similar incidents under peace conditions also, because the Service is always at war with its constant enemy--the sea. The boats have small buoyancy, and a leak is a dangerous thing; they are very vulnerable to the ram, and even in peace manoeuvres before the war we lost 6 boats from collisions either on the surface or diving. During the war we lost 61 boats, of which
7 were blown up without losses in personnel--these being the boats of the Baltic Flotilla.
20 were lost from a cause unknown. In other words, they went on patrol, and nothing more was heard of them. The enemy have no knowledge of their fate, and there were no survivors from them. Their loss was probably due to their striking mines.
5 were sunk by enemy submarines (one of them--"E 20"--in the Sea of Marmora).
3 were sunk while entering the Dardanelles, and 1 by gun-fire in the Marmora.
3 were wrecked on neutral coasts, 1 in the Baltic, and 1 on our own coast.
3 were sunk in error by gun or ram by our own side.
1 sank in harbour, 1 sank on trials, 1 was sunk by gun-fire after sinking a German destroyer off the Bight, and "C 3" blew herself up on St George's Day against the Mole at Zeebrugge.
The losses were heavy, but were not incurred uselessly. The boats were the outposts of the Fleet, and, however great the losses, they could never have equalled those the bigger ships would have had to endure had they been given the same patrols to perform.
Looking at the above list, one can see that the majority of the losses were due to mines. Losses by direct contact with the enemy were infrequent. This, of course, is because only a Fleet holding command of the sea can institute regular anti-submarine methods and patrols. Our boats were working in and around the Bight, and were taking the risks of mine-fields all the time. The five wrecks show that navigational difficulties are increased in war-time. This was found also by surface vessels. The Dardanelles took their toll; it was easy to do damage to traffic in the Marmora from a well-trained submarine, but getting in and out of the Narrows was no simple matter. Of the two sunk by air bombs, one was alongside in harbour, and the other was destroyed by an Allied aircraft which mistook her for a U-boat; the submarine could have easily dived and avoided attack, but was under the impression her unfortunate opponent was only closing in order to make signals. The three others sunk in error by our own side show that a submarine's risks are great even on her own coast, and that methods of identification can never be perfected. The enemy suffered more than we did from errors. They had several clashes between their own destroyers: on June 1 (the morning after Jutland) the _Stettin_ was fired on by the whole of their 2nd Battle Squadron; while one U-boat in 1914 successfully stalked and torpedoed another (U 5), thinking it was one of our own.