Convoy SL 125

German cryptographers decoded message traffic containing tactical information about convoy SL 125, and wolf pack Streitaxt (battle axe), consisting of {{GS|U-103|1940|2}}, {{GS|U-134|1941|2}}, {{GS|U-203||2}}, {{GS|U-409||2}}, {{GS|U-440||2}}, {{GS|U-509||2}}, {{GS|U-510||2}}, {{GS|U-572||2}}, {{GS|U-604||2}}, and {{GS|U-659||2}} was assembled 23 October to intercept the convoy west of the Canary Islands. The only United States merchant ship and escorting sloop {{HMS|Bridgewater|L01|6}}, {{sclass2|Isles|trawler|1}} HMS Copinsay and Free French corvette Commandant Drogou had been detached by the time U-203 found the convoy on 25 October. U-203 was depth charged and damaged while attempting to attack the straggling British tanker Anglo Maersk. The tanker was subsequently shadowed by U-134 and damaged by U-509.

The armed merchant cruiser and troopship HMS Esperance Bay was detached with the {{sclass2|Shakespearian|trawler|1}} HMS Juliet, tugboat HMS Salvonia, and repair ship HMNZS Kelantan when U-409 found and reported the main convoy of 37 ships on 27 October. Forty-one merchant shipsHague 2000 p.142 were left in the care of {{sclass2|Flower|corvette}}s {{HMS|Petunia|K79|2}},Rohwer & Hummelchen 1992 p.172 {{HMS|Cowslip|K196|2}}, {{HMS|Crocus|K49|2}}, {{citation needed span|text=HMS Dahlia, |reason=not listed by cited reference |date=January 2018}} and {{HMS|Woodruff|K53|2}}.Blair 1998 p.69Edwards 1999 p.116 U-659 was depth charged and damaged while attempting to attack the convoy. After moonrise, U-604 sank the damaged Anglo Maersk while U-509 torpedoed the British freighters Pacific Star and Stentor.

After unsuccessful submerged daylight attacks on 28 October, U-509 sank the British freighter Nagpore and damaged the British freighter Hopecastle after sunset. U-203 sank the damaged Hopecastle before dawn.Blair 1998 p.70

U-509 sank the British freighter Britanny during foul weather on the night of 29–30 October. The British tanker Bullmouth (sailing in ballast) was damaged by U-409 and sunk by U-659. The British freighter Corinaldo was damaged by both U-509 and U-659 before being sunk by U-203.

Improved weather brought coordinated attacks on the night of 30–31 October. U-409 torpedoed the British freighter Silverwillow while U-604 torpedoed the British transport President Doumer and the British freighter Baron Vernon. The British freighter Tasmania was damaged by U-659 and sunk by U-103. The Norwegian freighter Alaska was damaged by U-510, but reached England safely with the help of newly arriving escorts.

Long-range bombers of RAF Coastal Command arrived over the convoy on 31 October. Admiral Dönitz cancelled operations on the morning of 1 November. The convoy was reinforced with eleven more escorts and reached Liverpool on 9 November. It had suffered the greatest loss of any SL convoy,Hague 2000 pp.141-143 but its timing focused the available U-boats in the area away from the Operation Torch convoys for the allied invasion of North Africa on 8 November 1942. Some historians have suggested that the trade convoy SL 125 was an intentional tactical diversion to keep U-boats away from the loaded troop transports.Edwards 1999 p.115 Eleven of the ships surviving this convoy sailed two months later with convoy ON 154, in which four of them were sunk.{{cite web|url=http://www.convoyweb.org.uk/on/index.html|title=ON convoys|publisher=Andrew Hague Convoy Database|access-date=2011-05-25}}

• Convoy Battles of World War II

{{reflist|2}}

• {{cite book| title=Hitler's U-Boat War The Hunted 1942–1945 |author=Blair, Clay |publisher=Random House |year=1998 |ISBN =0-679-45742-9}}
• {{cite book| title=Dönitz and the Wolf Packs | url=https://archive.org/details/donitzwolfpacks0000edwa | url-access=registration |author=Edwards, Bernard |publisher=Brockhampton Press |year=1999 |ISBN =1-86019-927-5}}
• {{cite book| title=The Allied Convoy System 1939–1945 |author=Hague, Arnold |publisher=Naval Institute Press |year=2000 |ISBN =1-55750-019-3}}
• {{cite book| title=Chronology of the War at Sea 1939–1945 |author1=Rohwer, J. |author2=Hummelchen, G. |publisher=Naval Institute Press |year=1992 |ISBN =1-55750-105-X}}

SL125

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