Convoy ON 122

Convoy ON 122
Part of Battle of the Atlantic
Date 22–25 August 1942 Location North Atlantic Result German tactical victory
Belligerents
United Kingdom Norway	Germany
Commanders and leaders
CAPT S.N. White RNR LCDR J.V. Waterhouse RN	Admiral Karl Dönitz
Strength
36 freighters 1 destroyer 4 corvettes	9 submarines
Casualties and losses
4 freighters sunk (17,235 GRT) 40 killed/drowned

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.

Background

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.

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.

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 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. 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.

The ships in the convoy dispersed off Cape Cod on 3 September to proceed independently to North American ports.

Ships in convoy

Name	Flag	Dead	Tonnage	Cargo	Notes
Amberton (1928)			5,377 gross register tons (GRT)		destination Halifax
Athelprince (1926)			8,782 GRT		carried convoy commodore CAPT S.N. White RNR
Atland (1910)			5,203 GRT	coal	destination Saint John
Baron Herries (1940)			4,574 GRT		destination New York City
City of Lancaster (1924)			3,041 GRT	general cargo	destination New York City
Empire Breeze (1941)		1	7,457 GRT	(in ballast)	sunk by U-176 or U-438
Empire Chamois (1918)			5,684 GRT		destination New York City
Empire Wagtail (1919)			4,893 GRT		destination New York City
Fintra (1918)			2,089 GRT		destination Saint John
Gloxinia (1920)			3,336 GRT		destination New York City
Inger Elizabeth (1920)			2,166 GRT	coal	destination Halifax
Inger Toft (1920)			2,190 GRT		destination Sydney
Ingerfire (1905)			3,835 GRT	coal	destination Sydney
Ingman (1907)			3,169 GRT		destination Sydney
Isobel (1929)			1,515 GRT		destination Halifax
Jan (1920)			1,946 GRT		destination Herring Cove, Nova Scotia
Katvaldis (1907)		3	3,163 GRT	(in ballast)	sunk by U-605
Kolsnaren (1923)			2,465 GRT		destination New York City
Lifland (1920)			2,254 GRT		destination Montreal
Mariposa (1914)			3,807 GRT		destination New York City
Merchant Royal (1928)			5,008 GRT		destination Boston
Modlin (1906)			3,569 GRT		destination Halifax
Parismina (1908)			4,732 GRT		destination Boston
Ramava (1900)			2,141 GRT		destination Sydney
Rio Branco (1924)			3,210 GRT		destination Sydney
Rolf Jarl (1920)			1,917 GRT	coal	destination Halifax
Sheaf Mount (1924)		31	5,017 GRT	(in ballast)	sunk by U-605
Silverelm (1924)			4,351 GRT	general cargo	destination New York City
Sirehei (1907)			3,888 GRT		destination Sydney
Souliotis (1917)			4,299 GRT		destination Halifax
Stad Arnhem (1920)			3,819 GRT		destination New York City
Start Point (1919)			5,293 GRT		destination Botwood
Stockport (1911)			1,583 GRT		convoy rescue ship
Tenax (1925)			3,846 GRT		destination Sydney
Trolla (1923)		5	1,598 GRT	(in ballast)	sunk by U-438
Van de Velde (1919)			6,389 GRT	general cargo	destination New York City

References

• 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.