| Conflict: | Convoy ON 166 |
| Partof: | Battle of the Atlantic |
| Date: | 20–25 February 1943 |
| Place: | North Atlantic |
| Result: | German tactical victory |
| Combatant1: |  United Kingdom United States CanadaPoland |
| Commander1: | CAPT W E B Magee RN CAPT P.R. Heineman USN |
| Commander2: | Admiral Karl Dönitz |
| Strength1: | 63 freighters 1 destroyer 2 cutters 5 corvettes |
| Strength2: | 18 submarines |
| Casualties1: | 14 freighters sunk (87,994 GRT) 262 killed/drowned |
| Casualties2: | 3 submarines sunk 128 killed/drowned 11 captured |
Convoy ON 166 was the 166th of the numbered ON series of merchant ship convoys Outbound from the British Isles to North America. Sixty-three ships departed Liverpool 11 February 1943 and were met the following day by Mid-Ocean Escort Force Group A-3 consisting of the s and and the s,,, and .
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 for convoys with the advantage of intelligence gained through B-Dienst decryption of British Naval Cypher Number 3.[1] However, only 20 percent of the 180 trans-Atlantic convoys sailing from the end of July 1942 until the end of April 1943 lost ships to U-boat attack.[2]
On 20 February sighted the convoy scattered by sailing eight days in a northwesterly gale. torpedoed the straggling Norwegian Stigstad on the morning of 21 February. was sunk by a No. 120 Squadron RAF B-24 Liberator that afternoon, and Campbell attacked a U-boat that evening. Postwar analysis concluded that Campbell sank,[3] but more recent re-evaluation indicates the attack may have destroyed .[4]
torpedoed the British Empire Trader at 2032 and the Norwegian NT Nielsen Alonso at 0153 on the night of February 21–22. Both ships were hit by a single torpedo on the port side, flooding the forward hold, and boiler room, respectively.[5] from the following convoy ONS 167 was ordered to reinforce the convoy escort.
torpedoed the British Empire Redshank and American Chattanooga City and Expositor after sunset 22 February, but was damaged by depth charges from the recently arrived Burza. Campbell was disabled in a collision with U-606. Twelve men were rescued from the crew of the sinking U-boat. Burza left the convoy to tow Campbell back to port. The convoy rescue ship Stockport was sunk by U-604 while returning to the convoy after rescuing men from the three ships torpedoed by U-606.[6]
torpedoed the Panamanian Winkler at 0420 and Norwegian Glittre at 0425. torpedoed the American Hastings about 0430 and British Eulima at 0458 on 23 February.[5] Spencer, Rosthern and Chilliwack remained with the convoy and Dianthus left to refuel.[7]
torpedoed the Norwegian Ingria at 0520 before dawn on 24 February.[5] torpedoed the straggling American Liberty ship Jonathan Sturges.
U-628 hit the British Manchester Merchant with two torpedoes on the starboard side at 0527 before dawn 25 February.[5] [8]
The U-boats discontinued the attack on 26 February. The surviving ships in the convoy were joined by from Halifax, Nova Scotia on 28 February with escorts, and .[9] They reached New York City on 3 March 1943.[10]
| Name[11] | Flag | Dead | Tonnage | Cargo | Notes | |
|---|---|---|---|---|---|---|
| Amastra (1935) | | 8,031 gross register tons (GRT) | ||||
| Aruba (1929) |  | 3,979 GRT | general cargo | |||
| Beauregard (1920) | | 5,976 GRT | returned to England | |||
| Brasil (1935) |  | 8,130 GRT | ||||
| Charles H Cramp (1920) | | 6,220 GRT | straggled 1 March | |||
| Chattanooga City (1921) | | 0 | 5,687 GRT | (in ballast) | sunk by 22 Feb | |
| City of Canberra (1927) | | 7,484 GRT | carried convoy commodore Capt W E B Magee DSO RN | |||
| Delilian (1923) | | 6,423 GRT | ||||
| (1942) | | 7,177 GRT | 16 passengers | Liberty ship
| ||
| El Almirante (1917) |  | 5,248 GRT | returned to England | |||
| El Coston (1924) | | 7,286 GRT | joined from Iceland 16 Feb but returned to Iceland when leaking condenser caused water shortage | |||
| El Oceano (1925) | | 6,767 GRT | ||||
| (1942) | | 7,039 GRT | returned to England | |||
| (1942) | | 9,891 GRT | joined Halifax to New York; survived this convoy and convoy HX 229 | |||
| (1937) | | 6,007 GRT | ||||
| (1935) | | 5,023 GRT | ||||
| Empire Redshank (1919) | | 0 | 6,615 GRT | (in ballast) | torpedoed by & scuttled by escort 22 Feb | |
| Empire Trader (1908) | | 0 | 9,990 GRT | 985 tons chemicals | veteran of convoy HX 79; torpedoed by & scuttled by escort 23 Feb | |
| Empire Wordsworth (1942) | | 9,891 GRT | ||||
| Eulima (1937) | | 63 | 6,207 GRT | (in ballast) | sunk by 23 February | |
| Exilona (1919) | | 4,971 GRT | ||||
| Expositor (1919) | | 6 | 4,959 GRT | (in ballast) | sunk by & | |
| Fort Thompson (1942) | | 7,134 GRT | coal | |||
| Fort Vermillion (1942) | | 7,133 GRT | ||||
| Franz Klasen (1932) | | 1,194 GRT | ||||
| Gateway City (1920) | | 5,432 GRT | veteran of convoy PQ 18 | |||
| George W McKnight (1933) | | 2,502 GRT | ||||
| Glittre (1928) | | 3 | 6,402 GRT | (in ballast) | veteran of convoy ON 67; acting as escort oiler; sunk by & 23 Feb | |
| Gyda (1934) | | 1,695 GRT | general cargo | straggled and lost following 24 Feb collision with Fort Thompson | ||
| Hastings (1920) | | 9 | 5,401 GRT | (in ballast) | sunk by 23 Feb | |
| Ingria (1931) | | 0 | 4,391 GRT | (in ballast) | sunk by & 24 Feb | |
| (1942) | | 56 | 7,176 GRT | (in ballast) | Liberty ship straggled & sunk by 24 Feb | |
| Kaipaki (1939) | | 5,862 GRT | ||||
| Lechistan (1929) |  | 1,937 GRT | general cargo | straggled 20 Feb | ||
| Lochmonar (1924) | | 9,412 GRT | 28 passengers | ship's master was convoy vice commodore | ||
| Madoera (1922) | | 9,382 GRT | straggled 24 Feb & damaged by | |||
| Manchester Merchant (1940) | | 36 | 7,264 GRT | (in ballast) | sunk by 25 Feb | |
| (1942) | | 7,176 GRT | Liberty ship straggled with steering failure | |||
| Markay (1942) | | 10,342 GRT | joined from Iceland 16 Feb; romped 23 Feb | |||
| Molda (1937) | | 5,137 GRT | general cargo | |||
| N T Nielsen-Alonso (1900) | | 3 | 9,348 GRT | (in ballast) | sunk by & 22 Feb | |
| Pacific Exporter (1928) | | 6,734 GRT | ||||
| Pacific Grove (1928) | | 7,117 GRT | ||||
| Pan-Maine (1936) | | 7,237 GRT | ||||
| Pan-Maryland (1938) | | 7,701 GRT | ||||
| (1942) | | 7,191 GRT | Liberty ship veteran of convoy PQ 17 | |||
| Skandinavia (1940) | | 10,044 GRT | veteran of convoy ON 67 | |||
| Stigstad (1927) | | 3 | 5,964 GRT | (in ballast) | straggled & sunk by & 21 Feb | |
| Stockport (1911) | | 63 | 1,683 GRT | (rescued crewmen of sunken ships) | rescue ship; sunk by while rescuing survivors | |
| Tai Shan (1929) | | 6,962 GRT | 12 passengers | |||
| (1942) | | 7,176 GRT | Liberty ship romped & arrived New York 28 Feb | |||
| (1942) | | 7,176 GRT | Liberty ship returned to England | |||
| Tortuguero (1921) | | 5,285 GRT | ||||
| Tropic Star (1926) | | 5,088 GRT | ||||
| Wind Rush (1918) | | 5,586 GRT | ||||
| Winkler (1930) | | 20 | 6,907 GRT | (in ballast) | sunk by & 23 Feb |