All along England's south coast lie the sunken wrecks of German submarines - the U-boats. These fragile submersible craft formed the most potent weapon employed by the German Navy against Britain in two world wars. Dives on wrecks such as UB74, UB81 and U1195 fill the pages of many a diver's logbook. However, most know little about the U-boats, the battles they fought or the circumstances of their losses. Innes McCartney introduces this fascinating world.
The U-boat campaign of World War One represented the first major trial of the submarine as an offensive weapons platform. The sheer speed at which submarine design accelerated during the war years can be seen as an indication of how quickly both sides recognised its destructive potential.
At the war's outset, diesel propulsion was rare, boats were small, unreliable and generally seen as quirky little inventions that were useful for defending harbours and shorelines. By the end of the war, large powerful U-boats were marauding along the coast of the United States and fighting the first 'wolfpack' battles against allied convoys.
In the channel it wasn't long before the Royal Navy got its first, terrible taste of the potential of the U-boat. The 15,000 ton pre-dreadnought battleship HMS Formidable was torpedoed and sunk by U24 south of Portland on New Year's Day 1915. 547 sailors perished. The newness of the submarine as a weapon of war meant that unlike the U-boats of World War Two, countermeasures were not so effective and were much slower to appear in significant numbers.
Importantly, the rules of engagement for the submarine were far from clear and the practice of sinking merchant vessels without warning was shockingly new. The U-boat possessed all the attributes of a deadly and highly effective anti-commerce raider. It was in this role that the men of the Heligoland and Flanders flotillas mostly operated. The U-boat campaigns in both world wars became campaigns aimed at strangling Britain, the island race, into starvation and defeat.
World War One witnessed a much higher degree of savagery by both British and German seamen than was the case in World War Two. Some U-boat commanders cold-bloodedly killed fishermen and merchant sailors. For its part, Royal Navy personnel massacred the crew of U27 after the vessel had sunk.
In the channel, this savage new war was evidenced by the U-boats' sinking of vessels employed as Hospital ships. While these vessels, such as Warilda, Lanfranc and Donegal were clearly marked with the Red Cross, Germany claimed that they were also carrying arms and that therefore they were legitimate targets. A similar excuse was devised when the Lusitania was torpedoed without warning south of Ireland in 1915.
The channel remained a very active field of U-boat activity throughout the war and not surprisingly, therefore, the seabed is littered with U-boats and their victims. Divers are very familiar with many of their names - Afric, Moldavia, Shirala, Medina, Salsette, Kyarra, Alaunia and City of Brisbane are just a few. This carnage went on relatively uninterrupted until late in the war, when the Royal Navy finally and reluctantly adopted the convoy system. It was realised that if the rate of losses of merchant vessels was not stemmed quickly, Britain would starve. Calculations carried out at the time suggested that at one point, Britain had less than six weeks of food reserves.
Without plenty of independently sailing merchant ships spread out all around the British Isles, the job of the U-boat became harder. The seas appeared empty of easy prey, and where merchant ships were located, the ever-present destroyers were watchful and best left alone. To take on a destroyer, even in World War One was considered to be a very risky undertaking.
To operate in the channel the U-boats had to pass through the Dover Straits. This narrow stretch of water at the eastern end of the channel became a killing ground, accounting for around 21 U-boats during the war. Although standing orders generally prohibited U-boats from using the straits, many commanders chose to do so anyway and many paid a heavy price. The area was heavily netted, buoyed and mined and constantly being patrolled. Surfaced, the U-boats would generally make the run at night, at low water, when the mines and buoys were visible. The entire range of U-boat countermeasures available to the allies was deployed at one time or another in the channel. U-boats were attacked by aircraft, airships, Q-ships, mines, drifters, Naval vessels (including submarines) and merchant ships.
In a unique case, U103 was rammed and sunk by the Olympic, sister ship of the Titanic, as she steamed toward France. Other rare sinkings were achieved by British submarines which claimed UB72 and UC65. Also in one case, UC69 was lost after a collision with another U-boat.
1,426 German sailors in 54 U-boats from World War One lie in the channel.
After Germany's surrender in 1918, a substantial inventory of captured and surrendered U-boats fell into British and French hands. Several were disposed of in the channel. As far as the author has been able to work out, these fall into four distinct groups:
- Eight sent to Falmouth for demolition tests. Six were washed ashore in a gale and pieces are still visible on very low spring tides.
- Nine were dumped by the Royal Navy in mid-channel.
- Two were used by the French as gunnery targets.
- Six broke tow cables on the way to various breakers' yards.
Their presence (and possibly the presence of more unknown to the author at this time) adds to the difficulty in establishing the exact identity of many of the channel's submarine wrecks.
The U-boat campaign in the Second World War had a different complexion in the channel to that of the First World War. While the objectives of the German navy remained similar to those of World War One, the battle against Britain's mercantile lifeline was generally fought away from inshore waters. The great 'wolfpack' battles in the Atlantic were a thing of the past by the time that U-boats began to operate in the channel in numbers.
Three U-boats were in the Dover Straits in 1939 - U12, U16 and U40. After this time, U-boat command considered the channel too dangerous for anti-commerce operations. Therefore the channel saw no U-boat operations until June 1944, when the D-day landings took place and the U-boats had to intervene. This period of the U-boat war in World War Two is often referred to as the 'inshore campaign'. Largely ineffective in doing anything more that tying down massive anti-submarine resources, the U-boats operating in this period continued to fight until Germany surrendered.
The Ubootwaffe had been withdrawn from the Atlantic during 1943, having been defeated in its efforts to cut the steady flow of convoys to Britain. During the period from this withdrawal to D-day, much was done to the U-boats to give them enhanced fighting capabilities and greater chances of survivability. The Type VIIC U-boat, the mainstay of the Ubootwaffe, was effectively a submersible, not a true submarine. It was designed to dive to escape attack and to remain submerged for only a few hours at a time. When it surfaced it needed to recharge its batteries, running its diesel engines, and to replace the foul air in the boat. However, running on the surface anywhere around the British Isles in 1944 was almost certain to bring about an attack from the air. Radar equipped aircraft had become the nemesis of the U-boat.
Therefore after July 1944 only schnorchel equipped U-boats operated in the channel. The schnorchel enabled the U-boat to operate entirely submerged because it could run its diesels underwater. Although this device clearly saved many boats from certain destruction, it robbed the U-boat of much of its offensive punch. A schnorchelling U-boat could average only around 2 knots speed and was virtually blind, having only a periscope to see where it was going. The slowness of a schnorchelling U-boat meant that travelling from bases in Norway to the channel (after the French Atlantic bases were lost) could take several weeks.
The conditions, in which these late-war U-boat crews lived and died, are almost unimaginable. The foul air, stench of humanity, inability to eject rubbish and constant stress made life extremely tough. Schnorchelling was also very unpopular with crews, because it was uncomfortable and dangerous. When a wave shut the valve in the schnorchel head, the diesels simply used the air in the boat, causing nausea, burst eardrums and on occasion, carbon monoxide poisoning.
The channel was also home to the most concentrated anti-submarine force ever assembled. Around 1200 ships and hundreds of aircraft patrolled day and night, looking and listening for their quarry. By this time in the war allied escort groups and aircraft were highly experienced U-boat killers and once detected, the chances of survival for a U-boat were not high.
The experience of the anti-submarine forces was starkly contrasted by the inexperience of the U-boat crews and commanders. The best U-boat crews were either dead already or thinly spread around new boats being commissioned. It was not uncommon at this time for as little as five or six members of a crew to have much combat experience. The following is an excerpt from the log of a U-boat which operated in the channel:
'1645 South of Isle of Wight. Bottomed again in 55m. Enemy still has contact. I shall wait till night. Depth charges now fewer and further between. 34 nearby between 1600 and 2000. Despite the addition of oxygen and the issue of potash cartridges, the air is foul. A very great quantity of air has been used by crew who had to be moved in order to trim the boat during my attempt to shift position. The crew are becoming exhausted. It is nearly 30 hours since the boat was last ventilated. The first cases of vomiting occur, and I issue each man with a new potash cartridge. Breathing becomes distressed. The enemy escort group is still active overhead.... During 30 hours of pursuit, 252 depth charges have been dropped...'

U-Boat Losses in the Channel
Cause of loss	WW1	Between Wars	WW2	Total
Mine	11		5	16
Naval Vessel	9		8	17
Aircraft			10	10
Merchant Vessel	4			4
Q-Ship	4			4
Submarine	2			2
Accident	2		1	3
Combined Attack	8		13	21
Unknown	14		5	19
Dumped		23		23
Total	54	23	42	119

Nevertheless, U-boats continued to attempt to interdict the D-day traffic until the last day of the war. While the impression they made on the material crossing the channel was negligible, they did score a few notable successes. These included the 12,000 ton troopship Leopoldville which was torpedoed by U486 on Christmas Eve 1944. More than 800 American soldiers perished. U480 (which was later mined in the channel) accounted for the Canadian Corvette, HMCS Alberni and the Minesweeper HMS Loyalty.
However to attack allied shipping was to invite a counter-attack from escorting forces, which inevitably led to destruction of several U-boats. U772 was sunk after torpedoing the vessel Black Hawk near Weymouth and U1195 suffered the same fate after torpedoing the liner Cuba in the approaches to Portsmouth.
The U-boat command had no choice but to continue to fight right to the bitter end. It is now known that only a 50% chance of survival was expected from a U-boat operating in the channel. To survive a sinking was a rare event. 1636 German sailors lie in 42 'Iron coffins' in the channel from World War Two.
3062 German submariners have been lost in 96 U-boats in the channel during the twentieth century. The greatest U-boat killer in the channel was the naval vessel, accounting for seventeen confirmed kills independently and many more in combination with other vessels and aircraft. The high number of losses due to unknown causes makes the identification of U-boats in known positions very tricky.

By Innes McCartney.