Military Wiki
Convoy ON 166
Part of Battle of the Atlantic
Mk VII depth charge.jpg
A depth charge being loaded onto a depth-charge thrower aboard the corvette HMS Dianthus
Date20–25 February 1943
LocationNorth Atlantic
Result German tactical victory
Naval Ensign of the United Kingdom.png United Kingdom
United States Navy United States
Canada Canada
Poland Poland
War Ensign of Germany 1938-1945.svg Germany
Commanders and leaders
CAPT P.R. Heineman USN
Admiral Karl Dönitz
63 freighters
1 destroyer
2 cutters
5 corvettes
18 submarines
Casualties and losses
14 freighters sunk (87,994GRT)
262 killed/drowned
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 USCG Treasury Class Cutters Campbell and Spencer and the Flower class corvettes Dianthus, Chilliwack, Rosthern, Trillium and Dauphin.


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]

21 February

On 20 February U-604 sighted the convoy scattered by sailing 8 days in a northwesterly gale. U-332 torpedoed the straggling Norwegian Stigstad on the morning of 21 February. U-623 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 U-225,[3] but more recent re-evaluation indicates the attack may have destroyed U-529.[4]

U-92 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] ORP Burza from the following convoy ONS 167 was ordered to reinforce the convoy escort.

22 February

U-606 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]

23 February

U-628 torpedoed thePanamanian Winkler at 0420 and Norwegian Glittre at 0425. U-186 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]

24 February

U-600 torpedoed the Norwegian Ingria at 0520 before dawn on 24 February.[5] U-653 torpedoed the straggling American Liberty ship Jonathan Sturges.

25 February

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 Empire Cavalier from Halifax, Nova Scotia on 28 February with escorts New Westminster, Blairmore and Rimouski.[9] They reached New York City on 3 March 1943.[10]

Ships in convoy

Name[11] Flag[11] Dead[7] Tonnage[11] Cargo[7] Notes[11]
Amastra (1935) United Kingdom 8,031 gross register tons (GRT)
Aruba (1929) Netherlands 3,979 GRT general cargo
Beauregard (1920) United States 5,976 GRT returned to England
Brasil (1935) Norway 8,130 GRT
Charles H Cramp (1920) United States 6,220 GRT straggled 1 March[5]
Chattanooga City (1921) United States 0 5,687 GRT (in ballast) sunk by U-606 22 Feb
City of Canberra (1927) United Kingdom 7,484 GRT carried convoy commodore Capt W E B Magee DSO RN
Delilian (1923) United Kingdom 6,423 GRT
Edward Rutledge (1942) United States 7,177 GRT 16 passengers Liberty ship; returned to England
El Almirante (1917) Panama 5,248 GRT returned to England
El Coston (1924) Panama 7,286 GRT joined from Iceland 16 Feb but returned to Iceland when leaking condenser caused water shortage[5]
El Oceano (1925) Panama 6,767 GRT
Empire Cato (1942) United Kingdom 7,039 GRT returned to England
Empire Cavalier (1942) United Kingdom 9,891 GRT joined Halifax to New York; survived this convoy and convoy HX 229
Empire Chivalry (1937) United Kingdom 6,007 GRT
Empire Confidence (1935) United Kingdom 5,023 GRT
Empire Redshank (1919) United Kingdom 0 6,615 GRT (in ballast) torpedoed by U-606 & scuttled by escort 22 Feb
Empire Trader (1908) United Kingdom 0 9,990 GRT 985 tons chemicals veteran of convoy HX 79; torpedoed by U-92 & scuttled by escort 23 Feb
Empire Wordsworth (1942) United Kingdom 9,891 GRT
Eulima (1937) United Kingdom 63 6,207 GRT (in ballast) sunk by U-186 23 February
Exilona (1919) United States 4,971 GRT
Expositor (1919) United States 6 4,959 GRT (in ballast) sunk by U-606 & U-303
Fort Thompson (1942) United Kingdom 7,134 GRT coal
Fort Vermillion (1942) United Kingdom 7,133 GRT
Franz Klasen (1932) Panama 1,194 GRT
Gateway City (1920) United States 5,432 GRT veteran of convoy PQ 18
George W McKnight (1933) United Kingdom 2,502 GRT
Glittre (1928) Norway 3 6,402 GRT (in ballast) veteran of convoy ON 67; acting as escort oiler; sunk by U-628 & U-603 23 Feb
Gyda (1934) United Kingdom 1,695 GRT general cargo straggled and lost following 24 Feb collision with Fort Thompson[5]
Hastings (1920) United States 9 5,401 GRT (in ballast) sunk by U-186 23 Feb
Ingria (1931) Norway 0 4,391 GRT (in ballast) sunk by U-600 & U-628 24 Feb
Jonathan Sturges (1942) United States 56 7,176 GRT (in ballast) Liberty ship straggled & sunk by U-653 24 Feb[5]
Kaipaki (1939) United Kingdom 5,862 GRT
Lechistan (1929) Poland 1,937 GRT general cargo straggled 20 Feb[5]
Lochmonar (1924) United Kingdom 9,412 GRT 28 passengers ship's master was convoy vice commodore
Madoera (1922) Netherlands 9,382 GRT straggled 24 Feb & damaged by U-653[5]
Manchester Merchant (1940) United Kingdom 36 7,264 GRT (in ballast) sunk by U-628 25 Feb
Mark Twain (1942) United States 7,176 GRT Liberty ship straggled with steering failure
Markay (1942) United States 10,342 GRT joined from Iceland 16 Feb; romped 23 Feb
Molda (1937) Norway 5,137 GRT general cargo
N T Nielsen-Alonso (1900) Norway 3 9,348 GRT (in ballast) sunk by U-92 & U-753 22 Feb
Pacific Exporter (1928) United Kingdom 6,734 GRT
Pacific Grove (1928) United Kingdom 7,117 GRT
Pan-Maine (1936) United States 7,237 GRT
Pan-Maryland (1938) United States 7,701 GRT
Samuel Chase (1942) United States 7,191 GRT Liberty ship veteran of convoy PQ 17
Skandinavia (1940) Norway 10,044 GRT veteran of convoy ON 67
Stigstad (1927) Norway 3 5,964 GRT (in ballast) straggled & sunk by U-332 & U-603 21 Feb[5]
Stockport (1911) United Kingdom 63 1,683 GRT (rescued crewmen of sunken ships) rescue ship; sunk by U-604 while rescuing survivors
Tai Shan (1929) Norway 6,962 GRT 12 passengers
Thomas B Robertson (1942) United States 7,176 GRT Liberty ship romped & arrived New York 28 Feb
Thomas Hooker (1942) United States 7,176 GRT Liberty ship returned to England
Tortuguero (1921) United Kingdom 5,285 GRT
Tropic Star (1926) Norway 5,088 GRT
Wind Rush (1918) United States 5,586 GRT
Winkler (1930) Panama 20 6,907 GRT (in ballast) sunk by U-628 & U-223 23 Feb


  • Hague, Arnold (2000). The Allied Convoy System 1939-1945. Naval Institute Press. ISBN 1-55750-019-3. 
  • 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. 
  1. Tarrant p.108
  2. Hague pp.132, 137-138,161-162,164&181
  3. Morison 1975 p.338
  4. Rohwer & Hummelchen 1992 p.194
  5. 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 "Convoy ON 166". Retrieved 2011-05-25. 
  6. Hague 2000 pp.92&162
  7. 7.0 7.1 7.2 Hague 2000 pp.161-162
  8. Hague 2000 p.162
  9. "CONVOY ON 166". Warsailors. Retrieved 15 March 2010. 
  10. Hague 2000 p.159
  11. 11.0 11.1 11.2 11.3 "ON convoys". Andrew Hague Convoy Database. Retrieved 2011-05-24. 

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