HG 70 was an Allied convoy of the HG (Homeward from Gibraltar) series during World War II. It was attacked by a pack of ten U-boats, without success. All U-boats were beaten off, and they sank no ships of the convoy. Two ships were lost to aircraft; 23 ships arrived safely.

Convoy HG 73
Part of World War II
Date10 August 1941 – 15 August 1941
Location
Belligerents

 Kriegsmarine

 Regia Marina
United Kingdom
Commanders and leaders
Admiral Karl Dönitz Comm: R Adm. EW Leir
SOE: unknown
Strength
8 U-boats
1 Italian submarines
25 merchant ships
22 escorts (in rotation)
Casualties and losses
4 U-boats damaged, forced to return to base 2 ships sunk

Forces involved

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HG 70 comprised 25 ships homeward bound from Gibraltar, many in ballast, or carrying trade goods.[1] The convoy commodore was R Adm. EW Leir, in the freighter Polo, and the convoy was protected by a Western Approaches Command escort group, consisting of five corvettes. The convoy escort was augmented during the first few days by the destroyer Avon Vale and the submarine Clyde, and two ASW trawlers. They were joined during the first part of the voyage by the destroyers Boreas and Eridge, and a second escort group from OG 70, comprising the sloop HMS Deptford, destroyers Nestor and Encounter, and the corvette Convolvulus; they were also reinforced at various times throughout the voyage as warships came and went.[2]

Ranged against them was an ad hoc (and unnamed) wolfpack of five U-boats, reinforced with a group of four U-boats returning from a cancelled mission to the South Atlantic, all captained by experienced skippers and all holders of the Knight's Cross.[3]

Action

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HG 70 sailed from Gibraltar on 9 August 1941,[1] and was reported almost immediately by German agents across the bay in neutral Spain; these were able to report the convoy's composition, escort strength and departure time. In response U boat Command (BdU) ordered five boats from a northerly patrol line (Group South) to intercept, and diverted four boats returning from a cancelled mission to the South Atlantic, at that time off the Canaries. He also summoned aircraft from KG 40, a unit of Fw 200 "Condors" based at Bordeaux, to patrol and report on the convoys progress.

On 10 August the convoy was sighted by U-79, from Group South, which commenced shadowing, but she was attacked by escorting ships and aircraft. She was driven under and lost contact.

On 11 August the convoy was found again, this time by U-93 from the Canaries group; she was found by an escorting aircraft, bombed and damaged so severely that she had to break off and return to base for repairs. The report from U-93 enabled U-79 to regain contact, and for U-94 from the Canaries group to join; Both were depth-charged heavily by escorts, but remained in contact. A third U-boat, U-331 from South group, also joined, but was also detected and driven off by the escorts, and had to break off due to damage. Also that day HG 70 was attacked by aircraft; two ships, Empire Hurst and Sud, were hit and reported sunk,[2] though other sources say Sud was still afloat on 14 August when she was found and sunk by Italian submarine Marconi[4] and by U-126,[5] en route to join the attack on HG 70.

On 12 August the convoy was sighted by a patrolling Condor, and another Freetown boat, U-123, joined the pursuit. She too was detected and counter-attacked; Her crew counted 126 depth-charges dropped on them, 36 of them close enough to damage the boat so severely that she too had to return to base for repairs.

Later HG 70 was found by U-109 and U-124, both returning from Freetown. Both U-boats were attacked before they could obtain a firing position. U-109 was driven off, and returned to base with damage; U-124 found it impossible to approach and also broke off the attack.

On 15 August BdU cancelled the operation against HG 70 and the convoy continued on without further incident, arriving at Liverpool on 23 August.[3][1]

Aftermath

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The attack on HG 70 was, for the Germans, a disastrous failure. Ten U-boats had been involved in the operation; none had been able to get close enough to fire on the merchant ships, and four had been so severely handled that h they had been obliged to return to base for repairs. Using radio-detection (HF/DF) to locate the U-boats as they broadcast their sighting reports, and by vigorously attacking any contact to drive them under and thus unable to keep up, the escorts kept the merchant ships in the convoy safe from attack.

The failure prompted BdU to consider loss of morale as a factor, and on their return three of the four older commanders (from the Freetown operation) were moved to shore posts.[3]

Ships involved

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Merchant ships

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Ships[2] Flag Tonnage
(GRT)
Notes
Alhama UK 1352  
Baltallinn UK 1303  
Baron Kelvin UK 3081  
Briarwood UK 4019  
British Coast UK 889  
Cara UK 1760  
City of Waterford UK 1017  
Csarda Panama 3882  
Dux Norwegian 1590  
Empire Bay UK 2824  
Empire Brook UK 2852  
Empire Hurst UK 2852 sunk by aircraft 11 Aug
Empire Kestrel UK 2674 Rear Comm.
Empire Snipe UK 2497  
Empire Tern UK 2479  
Flaminian UK 2711  
Gothland UK 1286  
Inger Lise Nor 1582  
Lissa UK 1511  
Menapia UK 902  
Philipp M UK 2085  
Polo UK 1950 Comm. R.Adm EW Leir DSO
Sud Yug 2589 hit by aircraft 11 Aug
Wallsend UK 3157 Vice Comm.

Escorts

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Ship[2] Type Joined Left Notes
HMS Avon Vale (L06) Hunt-class destroyer 9 Aug 14 Aug  
HMS Begonia (K66) Flower-class corvette 9 Aug 23 Aug  
HMS Black Swan (L57) Black Swan-class sloop 15 Aug 21 Aug from convoy OG 70
HMS Boreas (H77) B-class destroyer 11 Aug 13 Aug  
HMS Campbeltown (I42) Town-class destroyer 19 Aug ? from convoy OS 3
HMS Clyde (N12) River-class submarine 9 Aug 11 Aug  
HMS Convolvulus (K45) Flower-class corvette 11 Aug before 18 Aug from convoy OG 70,
to HG 71
Copeland Convoy rescue ship 9 Aug 23 Aug 1526 tons
HMS Cossack (F03) Tribal-class destroyer 14 Aug ?  
HMS Deptford (U53) Grimsby-class sloop 11 Aug ? from OG 70
HMS Duncan (D99) D-class destroyer leader 15 Aug 19 Aug  
HMS Encounter (H10) E-class destroyer 11 Aug ? from OG 70
HMS Eridge (L68) Hunt-class destroyer 9 Aug 14 Aug  
HMS Faulknor (H62) F-class destroyer 10 Aug ? (returning to UK for repair)
HMS Jasmine (K23) Flower-class corvette 9 Aug 23 Aug  
HMS Lady Hogarth ASW Trawler 9 Aug ?  
HMS Lady Shirley ASW Trawler 9 Aug ?  
HMS Larkspur (K82) Flower-class corvette 9 Aug 23 Aug  
HMAS Nestor (G02) N-class destroyer 11 Aug 13 Aug from OG 70;
d/c damage 13 Aug
HMS Pimpernel (K71) Flower-class corvette 9 Aug 23 Aug  
HMS Rhodedendron (K78) Flower-class corvette 9 Aug ?  
HMS Stork (L81) Bittern class sloop 13 Aug ? from OG 71
HMS Wild Swan (D62) Modified W-class destroyer 11 Aug 15 Aug  

German U-boats

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U-boat[3] Type First contact Notes
U-79 Type VIIC 10 Aug  
U-93 Type VIIC 11 Aug  
U-94 Type VIIC 11 Aug  
U-109 Type IXB 13 Aug  
U-123 Type IXB 12 Aug  
U-124 Type IXB ? 13 Aug  
U-126 Type IXC not found sank straggler Sud on 14 Aug[5]
U-331 Type VIIC 11 Aug  

Italian submarines

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Name Class First contact Notes
Guglielmo Marconi Marconi-class not found attacked straggler Sud on 14 Aug and left sinking; claimed by U-126.[4]

Notes

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  1. ^ a b c Hague p178
  2. ^ a b c d HG 70 at convoyweb
  3. ^ a b c d Blair p335
  4. ^ a b Marconi at regiamarina.net; retrieved 22 December 2018
  5. ^ a b Sud at uboat.net; retrieved 22 December 2018

References

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  • Blair, Clay (2000) [1996]. Hitler's U-boat War: The Hunters 1939–1942. Vol. I (Cassell ed.). New York: Random House. ISBN 978-0-304-35260-9.
  • Hague, Arnold (2000). The Allied Convoy System 1939–1945. ISBN 1-86176-147-3.