The convoys bringing vital supplies across the Atlantic were vulnerable to the 'wolf packs' of U-boats.
The convoys were particularly vulnerable in the 'Atlantic Gap' an area that was too far off the coast of America and England to be covered by land based anti submarine aircraft.
The convoy escorts had to be constantly vigilant for lurking 'grey wolves' that would pick off ships with their torpedoes and deck mounted guns. The U-boats favoured attacking at night so convoys often sailed in darkness and maintained radio silence.
The Destroyer escorts had the job of trying to keep the convoys together in the rough seas of the Atlantic and to protect them from attack.
The Allies had the advantage of direction finding equipment mounted on the escorts that could locate U-boats when they sent signals to the German Command.
Admiral Donitz refused to believe that the codes generated by Enigma coding machines used by the German Navy could be decoded by the allies and insisted the U-boats sent regular reports and weather observations.
The top secret Ultra decrypts of the German signals carried out by the code breakers in Bletchley Park, England were a vital part of the war in the Atlantic.
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The convoys were particularly vulnerable in the 'Atlantic Gap' an area that was too far off the coast of America and England to be covered by land based anti submarine aircraft.
The convoy escorts had to be constantly vigilant for lurking 'grey wolves' that would pick off ships with their torpedoes and deck mounted guns. The U-boats favoured attacking at night so convoys often sailed in darkness and maintained radio silence.
The Destroyer escorts had the job of trying to keep the convoys together in the rough seas of the Atlantic and to protect them from attack.
The Allies had the advantage of direction finding equipment mounted on the escorts that could locate U-boats when they sent signals to the German Command.
Admiral Donitz refused to believe that the codes generated by Enigma coding machines used by the German Navy could be decoded by the allies and insisted the U-boats sent regular reports and weather observations.
The top secret Ultra decrypts of the German signals carried out by the code breakers in Bletchley Park, England were a vital part of the war in the Atlantic.
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The Search for U-Boat U-548
"On 1 May 1944, a Liberator aircraft from No. 10 Squadron sighted U-548 under Kaptänleutnant Heinrich Zimmermann east of Conception Bay. The plane attacked, and Zimmermann returned fire and escaped under cover of darkness. *
However, an alert was broadcast, and when U-548 surfaced off Cape Broyle two days later, HMS Hargood was waiting. Zimmermann took refuge close to the cliffs and while the British warship was conducting its search for the U-boat, the schooner Mary Coady, homeward bound from St. John’s, entered the search area.
The Hargood intercepted the Mary Coady and ordered its captain Tom Coady to spend the night out at sea while they hunted the U-boat. Coady complied and left the area. After approximately an hour, one of the crew happened to look over the side of the boat and saw a dark shape underneath keeping pace.
The Mary Coady did not have a radio or any way of calling for help, so the captain maintained his course, hoping that in the coming darkness the U-boat would move off. This was the case and, in the morning, the U-boat was gone."
Extract from the Newfoundland and Labrador Heritage website Other U-Boat Encounters (heritage.nf.ca)
"On 1 May 1944, a Liberator aircraft from No. 10 Squadron sighted U-548 under Kaptänleutnant Heinrich Zimmermann east of Conception Bay. The plane attacked, and Zimmermann returned fire and escaped under cover of darkness. *
However, an alert was broadcast, and when U-548 surfaced off Cape Broyle two days later, HMS Hargood was waiting. Zimmermann took refuge close to the cliffs and while the British warship was conducting its search for the U-boat, the schooner Mary Coady, homeward bound from St. John’s, entered the search area.
The Hargood intercepted the Mary Coady and ordered its captain Tom Coady to spend the night out at sea while they hunted the U-boat. Coady complied and left the area. After approximately an hour, one of the crew happened to look over the side of the boat and saw a dark shape underneath keeping pace.
The Mary Coady did not have a radio or any way of calling for help, so the captain maintained his course, hoping that in the coming darkness the U-boat would move off. This was the case and, in the morning, the U-boat was gone."
Extract from the Newfoundland and Labrador Heritage website Other U-Boat Encounters (heritage.nf.ca)
May 1944 - Hargood attacked by U-548 off the coast of Newfoundland
On 23 April 1944 the Canadian Eastern Command were alerted by Ultra Intelligence signal decrypts to the presence of the U-548 and knew it was heading towards St John’s Newfoundland.
Canadian Air Force Canso’s from Torbay, Newfoundland, and B-24 Liberators from Gander began to hunt for the submarine on that day. Unfortunately, the weather closed in and flying was restricted to a few hours a day and by 1st May 1944 the U-548 had reached Conception Bay undetected.
The U-548 was commanded by 27-year-old Eberhard Zimmerman and it was equipped with the new 'Destroyer Killer' acoustic T-5 torpedoes that homed in on the noise of a ship’s propellers.
Although it was May the sea was icy and the U-Boat could hide at periscope depth amongst the icebergs that cluttered the area.
On the afternoon of 1st May the U-548 surfaced east of the bay to ventilate the boat with fresh air and a Liberator of 10 Squadron, returning to base after a long convoy escort, saw the U-boat in the distance.
U-548 crash dived and the U-boat captain thought, wrongly, that the aircraft had not sighted the submarine, but within two hours a “Code Salmon” [a hunt to exhaustion] had been ordered. *
The Liberator had also dropped sonobuoys and was able to follow the U-boat's course. Passing the limit of its endurance, the Liberator then had to return to base before a Canso from 5 Squadron arrived on the scene, shortly to be relieved by another Liberator. The weather closed in, forcing this aircraft to leave as well, but over the next 24 hours twenty-one ships joined in the hunt, assisted when flying conditions permitted, by two Liberator, three Canso, and six Hudson sorties.
U-548 had seen the large number of ships and aircraft arriving late on 1st May and had shifted position to the south, miles away from the main search.
On the night of 3rd May 1944 HMS Hargood was off the coast of Newfoundland, East of Conception Bay.
The newly commissioned Hargood had safely escorted the straggling SS Baltrover into St.Johns, Newfoundland.
The SS Baltrover had been carrying passengers and cargo as part of Convoy (Outbound North) ON.233 that had left Liverpool on 20 April 1944 bound for New York.
When the U-548 surfaced after dusk it was startled to find the destroyer-escort HMS Hargood a little more than a mile away. The U-boat assumed it was a US Navy Destroyer.
The U-boat attacked the Hargood with a homing T5 torpedo from 2500 meters which missed just as a Canadian Air Force Liberator of 10 Squadron appeared on the scene. Moments later, as the U-548 closed in to take a second shot, HMS Hargood was suddenly illuminated by the brilliant searchlight of the Liberator.
The aircrew had picked up the Hargood on their radar whilst searching for U-548. After illuminating HMS Hargood with their Leigh Light, they then fired an identification flare that failed to function properly.
The U-boat captain thought he was under attack and immediately responded with 20mm AA flak, crash dived, and lay still on the seabed to avoid detection.
The airmen, incensed at being shot at, apparently by a friendly vessel, promptly flew away.
Neither the Hargood nor the Liberator had spotted the U-548 concealed amongst the ice floes.
The British seamen on board Hargood were thoroughly bewildered. The Hargood continued its patrol and appears to have searched for the U-boat as the U-548’s log records a 'shrill, undulating turbine noise' overhead for more than an hour.
The Hargood made no contact with U-548 that remained silently submerged on the ocean floor.
The Hargood signalled to flag officer Newfoundland:
'At 0800z* aircraft circled ship in position 47 31 N 52 02W when on bearing 045" appeared to have short bursts of Oerlikon [gunfire] fired at it . . . Have you any information? Continuing patrol. '
The whole affair was put down as an unsolved mystery and the hunt for U-548 was called off on 3 May 1944.
(08:00 Z (Zulu) time is Greenwich Mean Time - 02:00 am local time)
The top secret Bletchley Park and Admiralty files only started to be released from 1977 so seems unlikely the crew ever knew of the U-boat attack and their lucky escape. *Accounts differ regarding the RCAF's Liberator's first encounter with U-548.
The code "BB6652" is the Grid reference used by U-boats to map the Atlantic (Grid System) uboat.net - The U-boat War in Maps
On 23 April 1944 the Canadian Eastern Command were alerted by Ultra Intelligence signal decrypts to the presence of the U-548 and knew it was heading towards St John’s Newfoundland.
Canadian Air Force Canso’s from Torbay, Newfoundland, and B-24 Liberators from Gander began to hunt for the submarine on that day. Unfortunately, the weather closed in and flying was restricted to a few hours a day and by 1st May 1944 the U-548 had reached Conception Bay undetected.
The U-548 was commanded by 27-year-old Eberhard Zimmerman and it was equipped with the new 'Destroyer Killer' acoustic T-5 torpedoes that homed in on the noise of a ship’s propellers.
Although it was May the sea was icy and the U-Boat could hide at periscope depth amongst the icebergs that cluttered the area.
On the afternoon of 1st May the U-548 surfaced east of the bay to ventilate the boat with fresh air and a Liberator of 10 Squadron, returning to base after a long convoy escort, saw the U-boat in the distance.
U-548 crash dived and the U-boat captain thought, wrongly, that the aircraft had not sighted the submarine, but within two hours a “Code Salmon” [a hunt to exhaustion] had been ordered. *
The Liberator had also dropped sonobuoys and was able to follow the U-boat's course. Passing the limit of its endurance, the Liberator then had to return to base before a Canso from 5 Squadron arrived on the scene, shortly to be relieved by another Liberator. The weather closed in, forcing this aircraft to leave as well, but over the next 24 hours twenty-one ships joined in the hunt, assisted when flying conditions permitted, by two Liberator, three Canso, and six Hudson sorties.
U-548 had seen the large number of ships and aircraft arriving late on 1st May and had shifted position to the south, miles away from the main search.
On the night of 3rd May 1944 HMS Hargood was off the coast of Newfoundland, East of Conception Bay.
The newly commissioned Hargood had safely escorted the straggling SS Baltrover into St.Johns, Newfoundland.
The SS Baltrover had been carrying passengers and cargo as part of Convoy (Outbound North) ON.233 that had left Liverpool on 20 April 1944 bound for New York.
When the U-548 surfaced after dusk it was startled to find the destroyer-escort HMS Hargood a little more than a mile away. The U-boat assumed it was a US Navy Destroyer.
The U-boat attacked the Hargood with a homing T5 torpedo from 2500 meters which missed just as a Canadian Air Force Liberator of 10 Squadron appeared on the scene. Moments later, as the U-548 closed in to take a second shot, HMS Hargood was suddenly illuminated by the brilliant searchlight of the Liberator.
The aircrew had picked up the Hargood on their radar whilst searching for U-548. After illuminating HMS Hargood with their Leigh Light, they then fired an identification flare that failed to function properly.
The U-boat captain thought he was under attack and immediately responded with 20mm AA flak, crash dived, and lay still on the seabed to avoid detection.
The airmen, incensed at being shot at, apparently by a friendly vessel, promptly flew away.
Neither the Hargood nor the Liberator had spotted the U-548 concealed amongst the ice floes.
The British seamen on board Hargood were thoroughly bewildered. The Hargood continued its patrol and appears to have searched for the U-boat as the U-548’s log records a 'shrill, undulating turbine noise' overhead for more than an hour.
The Hargood made no contact with U-548 that remained silently submerged on the ocean floor.
The Hargood signalled to flag officer Newfoundland:
'At 0800z* aircraft circled ship in position 47 31 N 52 02W when on bearing 045" appeared to have short bursts of Oerlikon [gunfire] fired at it . . . Have you any information? Continuing patrol. '
The whole affair was put down as an unsolved mystery and the hunt for U-548 was called off on 3 May 1944.
(08:00 Z (Zulu) time is Greenwich Mean Time - 02:00 am local time)
The top secret Bletchley Park and Admiralty files only started to be released from 1977 so seems unlikely the crew ever knew of the U-boat attack and their lucky escape. *Accounts differ regarding the RCAF's Liberator's first encounter with U-548.
The code "BB6652" is the Grid reference used by U-boats to map the Atlantic (Grid System) uboat.net - The U-boat War in Maps
Government Code and Cypher reports on the signals sent by U-548 after the attack on HMS Hargood
A technician cleans a 'Leigh Light' on a Liberator - the powerful searchlight was used to illuminate U-boats
Translation of Captain Zimmerman's Action Report
The U-548 then took up a position south of Cape Race, lying quietly among the ice clutter at periscope depth, a tactic that made it virtually impossible to detect.
Around midnight on the 6th May, the mid-ocean Escort Group C1 crossed the search area, hurrying for St John's, Newfoundland, after a long spell of escort duty, and ran over U-548's hiding place.
As no U-boats were suspected in the vicinity the order was given for the escort group to cease zigzagging as it was proving difficult amongst the numerous icebergs.
(The U-boat's Action report contradicts this information and says the Destroyer was zig-zagging)
None of the group were streaming their CAT [Counter Acoustical Torpedo] Foxer noise making devices that were designed to deflect acoustic homing torpedoes.
The U-548 fired a T-5 acoustic homing torpedo from 1,500 yards at the nearest vessel in the group.
The torpedo exploded on the port side of the HMCS Valleyfield and within three minutes the Canadian frigate had broken in half and sunk plunging the crew into the icy water. There were only thirty-eight survivors from the 163 men on board.
After the attack the U-548 again descended to the ocean bottom and laid doggo for four hours evading the Canadian anti-submarine efforts.
Around midnight on the 6th May, the mid-ocean Escort Group C1 crossed the search area, hurrying for St John's, Newfoundland, after a long spell of escort duty, and ran over U-548's hiding place.
As no U-boats were suspected in the vicinity the order was given for the escort group to cease zigzagging as it was proving difficult amongst the numerous icebergs.
(The U-boat's Action report contradicts this information and says the Destroyer was zig-zagging)
None of the group were streaming their CAT [Counter Acoustical Torpedo] Foxer noise making devices that were designed to deflect acoustic homing torpedoes.
The U-548 fired a T-5 acoustic homing torpedo from 1,500 yards at the nearest vessel in the group.
The torpedo exploded on the port side of the HMCS Valleyfield and within three minutes the Canadian frigate had broken in half and sunk plunging the crew into the icy water. There were only thirty-eight survivors from the 163 men on board.
After the attack the U-548 again descended to the ocean bottom and laid doggo for four hours evading the Canadian anti-submarine efforts.
The submarine waited for three days, until it was well clear of the shore, some 360 kilometres south of Cape Race, before it signalled news of its victory to U-boat headquarters.
The signal includes a weather report and notes that it had fired a T-5 torpedo that missed a Destroyer and had later sunk another Destroyer. The signal was later decrypted at Bletchley Park (see picture above).
Accurate direction-finder bearings on the signal immediately brought a search by US warships and aircraft that were escorting a convoy in the vicinity. Canadian aircraft and warships then continued the hunt until 12 May 1944.
The U-548 eventually returned to its U-boat pen in Lorient, France on 24 June 1944.
The U-548 was later sunk with all hands on its fourth patrol on 19 April 1945.
Captain Zimmerman had left the ship by then and survived the war.
________________________________________________________________________________________________________________
Translation of U-548’s KTB (Action Report) kindly supplied by Jerry Mason
The full Action Report of the first patrol of the U-548 available here.
http://uboatarchive.net/U-548/KTB548-1.htm
Includes the sinking of the HMCS Valleyfield and diagrams of the attacks. Translation plus original documents.
The signal includes a weather report and notes that it had fired a T-5 torpedo that missed a Destroyer and had later sunk another Destroyer. The signal was later decrypted at Bletchley Park (see picture above).
Accurate direction-finder bearings on the signal immediately brought a search by US warships and aircraft that were escorting a convoy in the vicinity. Canadian aircraft and warships then continued the hunt until 12 May 1944.
The U-548 eventually returned to its U-boat pen in Lorient, France on 24 June 1944.
The U-548 was later sunk with all hands on its fourth patrol on 19 April 1945.
Captain Zimmerman had left the ship by then and survived the war.
________________________________________________________________________________________________________________
Translation of U-548’s KTB (Action Report) kindly supplied by Jerry Mason
The full Action Report of the first patrol of the U-548 available here.
http://uboatarchive.net/U-548/KTB548-1.htm
Includes the sinking of the HMCS Valleyfield and diagrams of the attacks. Translation plus original documents.
June 1944 to May 1945 - English Channel
After anti submarine patrols in the Atlantic the Hargood was allocated to the Devonport Command for Convoy Escort duties nearer to home.
The Hargood is recorded as escorting a total of 29 convoys from June 1944 to May 1945 mainly from the home ports across the English Channel to France and the Continent.
After anti submarine patrols in the Atlantic the Hargood was allocated to the Devonport Command for Convoy Escort duties nearer to home.
The Hargood is recorded as escorting a total of 29 convoys from June 1944 to May 1945 mainly from the home ports across the English Channel to France and the Continent.