| Convoys ONS 18/ON 202 | |||||||
|---|---|---|---|---|---|---|---|
| Part ofBattle of the Atlantic/World War II | |||||||
| |||||||
| Belligerents | |||||||
 Germany |  United Kingdom Canada | ||||||
| Commanders and leaders | |||||||
| AdmiralKarl Dönitz | ONS 18: Comm: EO Cochrane Escort:LtCdr PW Burnett | ||||||
| Strength | |||||||
| Leuthen: : 21 U-boats | ONS 18: 5 warships | ||||||
| Casualties and losses | |||||||
| 3 U-boats | 6 ships: 3 warships | ||||||
ONS 18 andON 202 wereNorth Atlanticconvoys of theONS/ON series which ran during thebattle of the Atlantic inWorld War II. They were the subject of a majorU-boat attack in September 1943, the first battle in theKriegsmarine's autumn offensive, following the withdrawal from the North Atlantic route afterBlack May.
Following the defeats of May 1943, and the devastating losses incurred by theU-boat Arm (U-Bootwaffe, or UBW)Admiral Dönitz had withdrawn from attacks on the North Atlantic route while awaiting tactical and technical improvements. Chief among these was theT-5acoustic torpedo, with which (it was planned) the convoy escorts could be attacked and eliminated, leaving the merchant ships defenceless. By September 1943 these were ready, and U-boat Control (Befehlshaber der Unterseeboote,BdU) dispatcheda patrol group of 21 boats, code-namedLeuthen, to renew the attack on the North Atlantic route.
In September 1943 BdU had established the patrol lineLeuthen of 21 U-boats south ofGreenland; these were to intercept west-bound convoys as they were about to enter theGreenland Air Gap, where Allied aircraft were reckoned to be unable to operate due to the extreme range.Leuthen was to harry any convoy it encountered while crossing the gap, before breaking off to repeat the onslaught with the east-bound convoys.
On 12 September 1943 convoy ONS 18 leftLiverpool bound forHalifax.Composed of 27 ships it was protected by B-3 Escort Group, comprising 2 destroyers,Escapade andKeppel, the frigateTowy ( Cdr MB Evans RN, the Senior Officer:Escort), and 5 corvettes;Narcissus,Orchis,Roselys,Lobelia andRenoncule.ONS 18 was also accompanied by theMAC carrierEmpire MacAlpine.
WhenWestern Approaches Command became aware ofLeuthen, it was decided to reinforce ONS 18; the following convoy, ON 202 was ordered to close up, and a support group, SG 9, sent to join.
ON 202 had left Liverpool on 15 September, composed of 38 ships and escorted byCanadian escort group C-2, comprising 2 destroyers,Gatineau (commanded by Lt.Cdr PW Burnett RN, SOE) andIcarus; the frigateLagan, and 3 corvettes;Drumheller,Kamloops andPolyanthus.
Support Group 9 comprised destroyerSt Croix, frigateItchen (Cdr CE Bridgman RN, SOE) and 3 corvettes,Chambly,Morden andSackville.
Altogether the 65 ships were escorted by 19 warships, to face an attack from 21 U-boats.
On 19 September ONS 18 was sighted byU-270; after sending a sighting report she was authorized to attack.Closing inU-270 fired aT-5acoustic torpedo atLagan, damaging her stern, the first case of an Allied warship to be damaged by the new weapon.The escorts counter-attacked, butU-270 escaped, thoughEscapade was damaged by a misfire from herHedgehog. BothLagan andEscapade were forced to detach, returning to base under escort.
TheLeuthen boats closed in during 19 September, but 2 were attacked by air patrols, which, since the introduction of a number of Very Long Range (VLR)Liberators during the summer, had been extended into the Air Gap.U-341 was attacked and sunk by a Liberator from 10 SquadronRCAF.U-338 was attacked by a Liberator of 120 SqdnRAF which was credited with the kill; however post-war analysis showed thatU-338 was only damaged by this, though was later engaged and sunk by the corvetteDrumheller of C 2 group.
On the night of 19/20 severalLeuthen boats were in contact;U-260 attacked, but gained no hits.U-238 fired on 2 ships, sinking one,Theodore Dwight Weld, and damaging another,Frederick Douglass. She fell out of the convoy, and was sunk later in the day byU-645.
On 20/21 a dozen boats were in contact, and 8 were able to attack.U-305 hitSt Croix, which sank with the loss of 66 of her crew.U-952 hitPolyanthus, which exploded and sank, leaving 1 survivor.He, and 81 men fromSt Croix, were picked up byItchen.U-386 was damaged by depth-charge attack and was forced to retire;U-603 was ordered to rendezvous, but was thwarted by air attacks.
Leuthen remained in contact, and on the night of 21/22 renewed the attack.U-377 attacked, claiming hits, but these were not confirmed; she was attacked and damaged by aircraft and retired.U-230 attacked, but again no hits were confirmed, she also was attacked by an unidentified escort and forced to retire.U-229 was attacked and destroyed, this being credited toKeppel, Evans' flagship.U-422 was damaged by air attack, but was able to continue.
On 23 September the convoys reached theGrand Banks area, where fog hindered visibility both of the air patrols and the attackingLeuthen boats.U-238 was able to penetrate the escort screen and sank 3 ships;Skjelbred,Oregon Express, andFort Jemseg.U-666 torpedoedItchen; she sank, leaving just 3 survivors from her own crew and those ofPolyanthus andSt Croix she was carrying.U-952 sankSteel Voyager and damagedJames Gordon Bennett.U-758 attacked, but had no hits confirmed and was herself damaged by a depth-charge attack.
Poor visibility, fuel shortages, and fatigue now beset both U-boats and escorts, but BdU, believing the attack to have been a great success, orderedLeuthen to break off the attack.
Claims by the various boat amounted to 12 escorts and 9 ships sunk, and a further 2 ships damaged
Actual losses were 3 escorts and 6 ships, with another damaged, while 3 U-boats were destroyed with a further 3 damaged and forced to return to base.
Both convoys continued to their destinations, ONS 18 reaching Halifax on 29 September, while ON 202 arrived atNew York on 1 October.
Believing the new tactics and weapons to be a great success, BdU continued the offensive.Leuthen was disbanded, with 12 boats forming a new patrol line,Rossbach, joined by 9 boats from home bases to attack the next set of east-bound convoys.
The Admiralty were also encouraged by the result. Despite the losses, (which were serious), 90% of the ships had arrived safely. The losses, while serious, were no more grievous than during the battles of late 1942 and early 1943. Thus they were confident the escorts would be able to meet the challenge of the U-boat Arm's new weapons and tactics.
| Date | Name | Nationality | Casualties | GRT | Sunk by... |
|---|---|---|---|---|---|
| ONS 18 | ... | ... | ... | ... | ... |
| 23 September 1943 | Steel Voyager |  United States | 0 | 6,198 | U-952 |
| ON 202 | ... | ... | ... | ... | ... |
| 19/20 September 1943 | Theodore Dwight Weld | United States | 33 | 7,176 | U-238 |
| 20 September 1943 | Frederick Douglass | United States | 0 | 7,176 | U-238, U-645 |
| 23 September 1943 | Fort Jemseg |  United Kingdom | 1 | 7,134 | U-238 |
| 23 September 1943 | Oregon Express |  Norway | 8 | 3,642 | U-238 |
| 23 September 1943 | Skjelbred | Norway | 0 | 5,096 | U-238 |
| Date | Name | Nationality | Casualties | Type | Sunk by... |
|---|---|---|---|---|---|
| 20 September 1943 | HMCSSt Croix | Royal Canadian Navy | ? 147 | Town-class destroyer | U-305 |
| 20 September 1943 | HMS Polyanthus | Royal Navy | ? 88 | Flower-class corvette | U-952 |
| 23 September 1943 | HMS Itchen | Royal Navy | 227 | River-classfrigate | U-666 |
| Date | Number | Type | Location | Casualties | Sunk by... |
|---|---|---|---|---|---|
| 19 September 1943 | U-341 | VIIC | Atlantic, S of Iceland 58°40′N25°30′W / 58.667°N 25.500°W /58.667; -25.500 | 50 | Air attack byLib A, 10 SqdnRCAF[1][2] |
| 20 September 1943 | U-338 | VIIC | Atlantic, SW of Iceland 57°40′N29°48′W / 57.667°N 29.800°W /57.667; -29.800 | 51 | Possibly gunfire byHMCS Drumheller[3][4] |
| 21 September 1943 | U-229 | VIIC | Atlantic 54°36′N36°25′W / 54.600°N 36.417°W /54.600; -36.417 | 50 | Gunfire, ramming by HMSKeppel[5][6] |