Convoy ON 122
|Convoy ON 122|
|Part of Battle of the Atlantic|
| United Kingdom
|Commanders and leaders|
|CAPT S.N. White RNR
LCDR J.V. Waterhouse RN
|Admiral Karl Dönitz|
|Casualties and losses|
|4 freighters sunk (17,235 GRT)
Convoy ON 122 was a trade convoy of merchant ships during the second World War. It was the 122nd of the numbered series of ON convoys Outbound from the British Isles to North America. The ships departed Liverpool on 15 August 1942 and were joined on 17 August by Mid-Ocean Escort Force Group B-6 consisting of V and W class destroyer Viscount with the Norwegian-manned Flower class corvettes Potentilla, Eglantine, Montbretia, and Acanthus and the Convoy rescue ship Stockport.
As western Atlantic coastal convoys brought an end to the second happy time, Admiral Karl Dönitz, the Befehlshaber der U-Boote (BdU) or 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 B-6 fought three of these convoy battles in sequential voyages with convoys SC 104, ON 144, and HX 217.
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.
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 attacks.
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.
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. 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 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 Whitleys of No. 77 Squadron RAF on 3 September.
Ships in convoy
|Amberton (1928)||United Kingdom||5,377||Destination Halifax|
|Athelprince (1926)||United Kingdom||8,782||Carried convoy commodore CAPT S.N. White RNR|
|Atland (1910)||Sweden||5,203||Coal||Destination Saint John|
|Baron Herries (1940)||United Kingdom||4,574||Destination New York City|
|City of Lancaster (1924)||United Kingdom||3,041||General cargo||Destination New York City|
|Empire Breeze (1941)||United Kingdom||1||7,457||In ballast||Sunk by U-176 or U-438|
|Empire Chamois (1918)||United Kingdom||5,684||Destination New York City|
|Empire Wagtail (1919)||United Kingdom||4,893||Destination New York City|
|Fintra (1918)||United Kingdom||2,089||Destination Saint John|
|Gloxinia (1920)||United Kingdom||3,336||Destination New York City|
|Inger Elizabeth (1920)||Norway||2,166||Coal||Destination Halifax|
|Inger Toft (1920)||United Kingdom||2,190||Destination Sydney|
|Ingerfire (1905)||Norway||3,835||Coal||Destination Sydney|
|Ingman (1907)||United Kingdom||3,169||Destination Sydney|
|Isobel (1929)||Panama||1,515||Destination Halifax|
|Jan (1920)||Norway||1,946||Destination Herring Cove, Nova Scotia|
|Katvaldis (1907)||United Kingdom||3||3,163||In ballast||Sunk by U-605|
|Kolsnaren (1923)||Sweden||2,465||Destination New York City|
|Lifland (1920)||Denmark||2,254||Destination Montreal|
|Mariposa (1914)||United Kingdom||3,807||Destination New York City|
|Merchant Royal (1928)||United Kingdom||5,008||Destination Boston|
|Modlin (1906)||Poland||3,569||Destination Halifax|
|Parismina (1908)||United States||4,732||Destination Boston|
|Ramava (1900)||Latvia||2,141||Destination Sydney|
|Rio Branco (1924)||Norway||3,210||Destination Sydney|
|Rolf Jarl (1920)||Norway||1,917||Coal||Destination Halifax|
|Sheaf Mount (1924)||United Kingdom||31||5,017||In ballast||Sunk by U-605|
|Silverelm (1924)||United Kingdom||4,351||General cargo||Destination New York City|
|Sirehei (1907)||Norway||3,888||Destination Sydney|
|Souliotis (1917)||Greece||4,299||Destination Halifax|
|Stad Arnhem (1920)||Netherlands||3,819||Destination New York City|
|Start Point (1919)||United Kingdom||5,293||Destination Botwood|
|Stockport (1911)||United Kingdom||1,583||convoy rescue ship|
|Tenax (1925)||United Kingdom||3,846||Destination Sydney|
|Trolla (1923)||Norway||5||1,598||In ballast||Sunk by U-438|
|Van de Velde (1919)||Netherlands||6,389||General cargo||Destination New York City|
- Rohwer & Hummelchen p.157
- Hague pp.158&161
- "ON convoys". Andrew Hague Convoy Database. Retrieved 2012-09-19.
- Milner pp.148-150
- Tarrant p.108
- Hague pp.132, 137-138, 161-162, 164, 181
- Blair pp.662&663
- "Empire Breeze - British Steam merchant". www.uboat.net. Retrieved 29 October 2013.
- "Katvaldis - British Steam merchant". www.uboat.net. Retrieved 29 October 2013.
- "Sheaf Mount - British Steam merchant". www.uboat.net. Retrieved 29 October 2013.
- "Trolla - Norwegian Steam merchant". www.uboat.net. Retrieved 29 October 2013.
- Blair, Clay (1996). Hitler's U-Boat War: The Hunters 1939-1942. Random House. ISBN 0-394-58839-8.
- Hague, Arnold (2000). The Allied Convoy System 1939-1945. Naval Institute Press. ISBN 1-55750-019-3.
- Milner, Marc (1985). North Atlantic Run. Naval Institute Press. ISBN 0-87021-450-0.
- Morison, Samuel Eliot (1975). History of United States Naval Operations in World War II, Volume I The Battle of the Atlantic 1939-1943. Little, Brown and Company.
- Rohwer, J. and Hummelchen, G. (1992). Chronology of the War at Sea 1939-1945. Naval Institute Press. ISBN 1-55750-105-X.
- Tarrant, V.E. (1989). The U-Boat Offensive 1914-1945. Arms and Armour. ISBN 1-85409-520-X.