Convoy SL 125
Convoy SL 125 was the 125th of the numbered series of World War II convoys of merchant ships from Sierra Leone to Liverpool. Ships carrying commodities bound to the British Isles from South America, Africa, and the Indian Ocean travelled independently to Freetown, Sierra Leone to be convoyed for the last leg of their voyage. Thirty-seven merchant ships departed Freetown on 16 October 1942 and were joined at sea by five more.
Initial contact 
German cryptographers decoded message traffic containing tactical information about convoy SL 125, and wolf pack Streitaxt (battle axe), consisting of U-103, U-134, U-203, U-409, U-440, U-509, U-510, U-572, U-604, and U-659 was assembled 23 October to intercept the convoy west of the Canary Islands. The only United States merchant ship and escorting sloop HMS Bridgewater, Isles class trawler 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.
27 October 
The armed merchant cruiser and troopship HMS Esperance Bay was detached with the Shakespearian class trawler 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 ships were left in the care of Flower class corvettes Petunia, Cowslip, Crocus, and Woodruff. 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.
28 October 
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.
29 October 
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.
30 October 
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, 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. Eleven of the ships surviving this convoy sailed two months later with convoy ON 154, in which four of them were sunk.
Ships in convoy 
|Alaska (1918)||5,681 gross register tons (GRT)||torpedoed and fell out 31 Oct|
|Alexandre Andre (1928)||5,322 GRT|
|Amstelkerk (1929)||4,457 GRT||romped 30 Oct|
|Anglo Maersk (1930)||7,705 GRT||straggled 19 Oct; torpedoed by U-509 26 Oct but survived|
|Baron Elgin (1933)||3,942 GRT||detached to Funchal; survived this convoy, convoy ON 154, convoy SC 122 & convoy ONS 5|
|Baron Kinnaird (1927)||3,355 GRT|
|Baron Vernon (1929)||0||3,642 GRT||5,500 tons iron ore||sunk by U-604 30 Oct|
|Belnor (1926)||2,871 GRT||joined at sea 19 Oct|
|Bornholm (1930)||3,177 GRT||survived this convoy, convoy ON 154, & convoy ONS 5|
|Bothnia (1928)||2,407 GRT||joined at sea 23 Oct, survived this convoy & convoy HX 228|
|British Ardour (1928)||7,124 GRT||joined at sea 19 Oct as escort oiler|
|Brittany (1928)||14||4,772 GRT||7,132 tons general cargo||veteran of convoy HX 79; sunk by U-509 28 Oct|
|Bullmouth (1927)||50||7,519 GRT||(ballasted tanker)||sunk by U-409 & U-659 30 Oct|
|Calgary (1921)||7,206 GRT||survived this convoy & convoy ON 154|
|Clan Murray (1918)||5,953 GRT|
|Corinaldo (1921)||8||7,131 GRT||5,141 tons frozen meat||sunk by U-509, U-659 & U-203 30 Oct|
|Debrett (1940)||6,244 GRT|
|Dundrum Castle (1919)||5,259 GRT||veteran of convoy SC 42; survived this convoy & convoy ON 154|
|Empire Cougar (1919)||5,758 GRT||arrived with engine defects & later survived convoy ON 154|
|Empire Simba (1919)||5,691 GRT||survived this convoy & convoy ON 154|
|Germa (1920)||5,282 GRT|
|Guinean (1936)||5,205 GRT|
|Henry Stanley (1929)||5,026 GRT|
|Hopecastle (1937)||5||5,178 GRT||5,500 tons general cargo||sunk by U-509 & U-203 29 Oct|
|King Edward (1919)||5,224 GRT||survived to be sunk 2 months later in convoy ON 154|
|Lafonia (1911)||1,961 GRT|
|Lynton Grange (1937)||5,029 GRT||survived to be sunk 2 months later in convoy ON 154|
|Mano (1925)||1,418 GRT||joined at sea 23 Oct; survived this convoy & convoy ONS 5|
|Marquesa (1918)||8,979 GRT|
|Nagpore (1920)||19||5,283 GRT||1,500 tons copper & 5,500 tons general cargo||carried convoy commodore RADM Sir C N Reyne KBE; sunk by U-509 28 Oct|
|Pacific Star (1920)||0||7,591 GRT||5,037 tons refrigerated meat & general cargo||sunk by U-509 27 Oct|
|President Doumer (1934)||260||11,898 GRT||63 passengers & general cargo||joined at sea 19 Oct; sunk by U-604 30 Oct|
|San Francisco (1915)||4,933 GRT|
|Sembilan (1922)||6,566 GRT|
|Silver Willow (1930)||5||6,373 GRT||9,000 tons general cargo||sunk by U-409 30 Oct|
|Stentor (1926)||44||6,148 GRT||6,000 tons west African produce||carried convoy vice commodore Capt R H Garstin CBE RIN; sunk by U-509 27 Oct|
|Tasmania (1935)||2||6,405 GRT||8,500 tons food & iron||sunk by U-103 31 Oct|
|Tynemouth (1940)||3,168 GRT||veteran of convoy SC 94; survived this convoy & convoy ON 154|
|Ville de Rouen (1919)||5,083 GRT||survived to be sunk 2 months later in convoy ON 154|
|Welsh Trader (1938)||4,974 GRT|
|West Kebar (1920)||5,620 GRT||detached 20 Oct|
|Zarian (1938)||4,871 GRT||survived to be sunk 2 months later in convoy ON 154|
- Hague 2000 p.138
- "SL convoys". Andrew Hague Convoy Database. Retrieved 2011-05-24.
- Blair 1998 p.69
- Rohwer & Hummelchen 1992 p.172
- Hague 2000 p.142
- Edwards 1999 p.116
- Blair 1998 p.70
- Hague 2000 pp.141-143
- Edwards 1999 p.115
- "ON convoys". Andrew Hague Convoy Database. Retrieved 2011-05-25.
- Hague 2000 p.146
- Blair, Clay (1998). Hitler's U-Boat War The Hunted 1942-1945. Random House. ISBN 0-679-45742-9.
- Edwards, Bernard (1999). Dönitz and the Wolf Packs. Brockhampton Press. ISBN 1-86019-927-5.
- Hague, Arnold (2000). The Allied Convoy System 1939-1945. Naval Institute Press. ISBN 1-55750-019-3.
- Rohwer, J. and Hummelchen, G. (1992). Chronology of the War at Sea 1939-1945. Naval Institute Press. ISBN 1-55750-105-X.