The Graph was launched as U-570 from the Hamburg yard of Blohm & Voss on 20 March 1941. She was a Type VIIC submarine and was armed with 1@ 88mm deck gun, 5 @ 533mm torpedo tubes (4 bow and 1 stern), and 1 AA gun. She weighed in at 871dt. submerged and her dimensions were 213.0’ x 20.0’ x 16.0’. She was powered by 2 @ Mann diesel engines and 2 electric motors.
The story of HMS Graph began on 27th August, 1941 when she was captured from the Germans after an air attack. She had been on her first patrol from her base at Loh fjord in Norway and was under the command of Kapitanleutenant Hans Rahmlow.
On 27th August, U-570 spent most the early morning submerged to give her crew a respite from the sickening wallowing that many submarines suffered when they were on the surface. She finally surfaced around 10:50 am in approximate position 62.15 N, 18 35 W and was immediately detected by the radar of a nearby RAF Lockheed Hudson bomber of 269 Squadron operating from a base in Iceland. Rahmlow was in the conning tower and heard the approaching Hudson’s engines. He immediately ordered a crash dive but it was too late. The aircraft reached the submarine before she was fully submerged and dropped four 250-pound depth charges with the closest detonating just 10 yards from the boat. U-570 quickly resurfaced and around ten of the crew emerged. The Hudson opened fire on them with machine guns but stopped firing when they saw the U-boat crew flying a white flag of surrender. An account of what happened was subsequently given to British naval intelligence interrogators by the captured crew members—the depth charge explosions had almost rolled the boat over, knocked out all electrical power, smashed instruments, caused water leaks and contaminated the air on the boat. The inexperienced crew believed the contamination to be chlorine caused by acid from leaking battery cells mixing with sea-water, and the engine-compartment crew panicked and fled forward to escape the gas. The submarine was dead in the water and in darkness. Rahmlow believing the chlorine would kill his crew if they remained submerged had little choice but to resurface.
The sea was too rough for the crew to man their anti-aircraft gun so they surrendered to forestall another, probably fatal, depth charge attack from the Hudson. They were unaware the aircraft had dropped all its depth-charges. Most of the crew remained on the deck of the submarine as the Hudson circled above them. They had radioed for assistance and soon a Catalina of 209 Squadron arrived on the scene with a full load of depth-charges. The German crew radioed their situation to the German naval high-command, destroyed their radio, smashed their Enigma machine and dumped its parts overboard along with the boat’s secret papers. Admiral Dönitz later noted in his war diary that he ordered U-boats in the area to go to U-570’s assistance after receiving this report and the U-82responded, but was prevented from reaching the U-570 by Allied air patrols.
By early afternoon, fuel levels had forced the Hudson to return to her base in Iceland. The Catalina, a very long-range aircraft, was ordered to watch the submarine until more allied ships arrived. The first vessel to arrive was HMT Northern Chief allowing the Catalina to return to Iceland. She had been circling the submarine for 13 hours.
The German crew remained on board U-570 overnight making no attempt to scuttle their boat as Northern Chief had signalled she would open fire and not rescue survivors from the water if they did this. During the night, four more naval trawlers and the destroyers HMS Burwell and HMS Niagara reached the scene. At daybreak, there was a series of messages between the British and Germans, with the Germans repeatedly requesting to be taken off as they were unable to stay afloat, and the British refusing to evacuate them until they secured the submarine and stopped it from sinking. The British were concerned that the Germans would deliberately leave behind them a sinking U-boat if they were evacuated. The situation became more confused when a small Norwegian float-plane of 330 Squadron appeared and unaware of the surrender, attacked the U-570 with small bombs and fired on the Northern Chiefwhich also returned fire. No damage was done and Burwell ordered the aircraft away by radio.
In deteriorating weather several unsuccessful attempts were made to attach a tow-line to the U-boat. Believing the Germans were being obstructive, Burwell’scaptain, S.R.J. Woods ordered warning shots to be fired with a machine gun. Unfortunately five of the German crew were accidentally hit and slightly wounded. Finally four armed British sailors from the trawler HMS Kingston Agate reached the submarine and, after a quick search failed to find the U-boat’s Enigma machine, they attached a tow line and carried out the transfer of the five wounded men and the submarine’s officers to the Kingson Agate. The remaining crew were taken on board HMS Niagara, which by this time had come alongside the U-boat. The ships began slowly sailing to Iceland with the U-570 under tow and with a relay of planes from Iceland patrolling overhead. They arrived in Iceland at dawn on 29th August. There, the submarine was beached as she had been taking on water and was thought to be in danger of sinking.
Adolf Hitler, infuriated at loosing one of his new submarines in an act he regarded as cowardice ordered Rahmlow’s court martial and execution. Luckily for Rahmlow he was imprisoned in the UK and the order was never carried out. Meanwhile the submarine had been repaired and sailed to Vickers yard in Barrow in Furness where she was refitted and emerged as HMS Graph.
In early 1944 she was taken to Chatham Dockyard for a planned refit but as she was entering the dockyard she hit the harbour wall and was badly damaged. An understandable shortage of spare parts made a return to service impossible so she was decommissioned and towed to the Clyde to be used for depth charge tests. She was stripped of all of her internal fittings and left Chatham, under tow by the tug Empire John, in early March.
On the morning of March 18th they were in the North Channel when the weather deteriorated with 50 mph winds forcing them almost to a standstill. At 4:10am the 16″ manila tow line parted and the Graph drifted off into the night. Despite the efforts of the crew of the Empire John and HMS Bullen they could not get a second line aboard. The Graph was pitching and rolling in mountainous seas and at one point she even collided with the Empire John damaging the tug’s steering.
The tug was forced to leave the scene and to run for Campbeltown for repairs. The Bullen was joined by another tug, Allegiance, but still they could do nothing to stop the submarine drifting north towards Islay. She finally came ashore near Coul Point on the west coast around dawn on the 20th. During the next four weeks the wreck was smashed to pieces in a series of violent storms.
The Graph was later heavily salvaged and as a result there is only a small amount of wreckage remaining. Some of the salvage equipment is still visible ashore which helps to mark the site of the wreck. The remains are in position 55°48.216’N, 006°28.484’W (GPS) which is about three quarters of a mile north of Coul Point.
The wreckage lies in a gully close to the rocks running at a angle of forty five degrees to the shore. The gully is about 10 metres deep at the seaward end and slopes gradually to around 6 metres. Along the length of the gully the wreckage has been pounded into the seabed by the swell that almost continually affects the coastline here. There are a few larger pieces of wreckage and, like most of the wrecks along this coastline, the remaining brass items have been polished to a shine by the abrasive effect of swell and sand. This is a very difficult site to visit due to location and prevailing weather conditions, on reflection……. the effort to visit the site will probably not be rewarded by the dive.