Convoy ON 122 was a trade

convoy A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used ...

of merchant ships during the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. It was the 122nd of the numbered series of ON convoys Outbound from the British Isles to North America. The ships departed

Liverpool Liverpool is a port City status in the United Kingdom, city and metropolitan borough in Merseyside, England. It is situated on the eastern side of the River Mersey, Mersey Estuary, near the Irish Sea, north-west of London. With a population ...

on 15 August 1942 and were joined on 17 August by Escort Group B6 of the Mid-Ocean Escort Force.Milner pp.148-150

Background

As western Atlantic coastal convoys brought an end to the second happy time, Admiral

Karl Dönitz Karl Dönitz (; 16 September 1891 – 24 December 1980) was a German grand admiral and convicted war criminal who, following Adolf Hitler's Death of Adolf Hitler, suicide, succeeded him as head of state of Nazi Germany during the Second World ...

, the '' Befehlshaber der U-Boote'' (commander in chief of U-Boats), shifted focus to the mid-Atlantic to avoid aircraft patrols. Although convoy routing was less predictable in the mid-ocean, Dönitz anticipated that the increased numbers of U-boats being produced would be able to effectively search the area with the advantage of intelligence gained through '' B-Dienst'' decryption of British Naval Cypher Number 3. However, of the 180 trans-Atlantic convoys sailing from the end of July 1942 until the end of April 1943, only 20 percent lost ships to U-boat attack. The Norwegian-manned corvettes of Escort Group B6 fought three of these convoy battles in sequential voyages with convoys SC 104, ON 144, and HX 217.Hague pp.132, 137-138, 161-162, 164, 181

Discovery

''U-135'' discovered and reported the convoy on 22 August while patrolling a formerly assigned station after having missed the signal to change position. The initial report caused some confusion because of the unexpected position and a coding error, but after ''U-135'' sent two clarifying messages while shadowing the convoy, the wolf pack ''Lohs'' was ordered to converge on the convoy.Blair pp.662&663

Stalking

While the Norwegian corvettes investigated HF/DF bearings provided by ''Viscount'' and ''Stockport'' on 23 August, ''Viscount'' conserved fuel by declining to engage in long daylight stern chases with U-boats. ''Viscount'' and ''Potentilla'' attacked HF/DF contacts more aggressively through the hours of darkness, but were satisfied by simply forcing the U-boats to submerge rather than conducting sustained

depth charge A depth charge is an anti-submarine warfare (ASW) weapon designed to destroy submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited ...

attacks.

Attack

Visibility was reduced to 7,000 yards with patchy squalls under overcast skies on 24 August. As dusk approached, the escort had located only four of the nine U-boats in contact with the convoy. The convoy's course was altered to 267° at 2300Z. ''U-605'' torpedoed ''Katvaldis'' and ''Sheaf Mount'' on the starboard side of the convoy an hour after the course alteration. ''Viscount'' obtained a RADAR contact and forced the submarine to submerge. As ''Viscount'' was dropping depth charges, ''U-176'' and ''U-438'' entered the front of the convoy to torpedo ''Trolla'' and ''Empire Breeze''.

Disengagement

The convoy escorts effectively intercepted attacks through the pre-dawn hours of 25 August. The calm sea conditions were favourable for the Type 271 centimeter-wavelength RADAR with which all the escorts were equipped, and prompt counter-attacks prevented the U-boats from reaching torpedo launch positions. A depth charge attack by ''Eglantine'' holed the conning tower of ''U-605''.Rohwer & Hummelchen p.157 ''U-135'', ''U-174'' and ''U-438'' were also damaged by depth charges. The shadowing U-boats lost contact after the convoy entered heavy fog after daybreak on 25 August, and discontinued pursuit on 26 August. ''U-256'' was under repair for more than a year after being bombed in the

Bay of Biscay The Bay of Biscay ( ) is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward ...

on 31 August following depth charge damage from ''Viscount'' and ''Potentilla''. ''U-438'' aided ''U-256'' reaching port, and ''U-174'' refueled three ''Lohs'' U-boats before returning to France to repair damage. ''U-705'' suffered several casualties when hit by gunfire from the convoy escorts; and was sunk in the Bay of Biscay by

Armstrong Whitworth Whitley The Armstrong Whitworth A.W.38 Whitley was a British medium/heavy bomber aircraft of the 1930s. It was one of three twin-engined, front line medium bomber types that were in service with the Royal Air Force (RAF) at the outbreak of the World W ...

s of No. 77 Squadron RAF on 3 September. The ships in the convoy dispersed off

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer months. The ...

on 3 September to proceed independently to North American ports.

Ships in the convoy

Allied merchant ships

A total of 37 merchant vessels joined the convoy, either in Liverpool or later in the voyage.

Convoy escorts

The armed military ships of Escort Group B6, from the Mid-Ocean Escort Force, escorted the convoy during much of its journey.

Notes

References

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