Convoy ON 154 (alternatively Convoy ON(S) 154 or Convoy ONS 154) was a North Atlantic convoy of the ON convoys which ran during the battle of the Atlantic in the Second World War. It was the 154th of the numbered series of merchant ship convoys Outbound from the British Isles to North America. It came under attack in December 1942 and lost 13 of its 50 freighters; one U-boat was sunk.
Background
As western Atlantic coastal convoys brought an end to the second happy time, Admiral Karl Dönitz, the Befehlshaber der U-Boote (BdU, commander in chief U-boats) shifted focus to the mid-Atlantic to avoid aircraft patrols. Although convoy routing was less predictable in mid-ocean, Dönitz anticipated that the increased numbers of U-boats being produced would be able to search for convoys. Only 20 per cent 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.
Bletchley Park
The British Government Code and Cypher School (GC&CS) based at Bletchley Park housed a small industry of code-breakers and traffic analysts. By June 1941, the German Enigma machine Home Waters (Heimish) settings used by surface ships and U-boats could quickly be read. On 1 February 1942, the Enigma machines used in U-boats in the Atlantic and Mediterranean were changed to a four-rotor Enigma (Shark to the British). By mid-1941, British Y-stations were able to receive and read Luftwaffe W/T transmissions and give advance warning of Luftwaffe operations. In November 1942 the diversion of U-boats to North-West Africa against Operation Torch reduced losses on Atlantic convoys but world losses rose to 721,700 long tons (733,300 t) the worst month of the war. Only two U-boat s were sunk in November. In mid-December GC&CS began to break the four-rotor enigma messages. Having broken one Shark cypher in mid-December, the delay in breaking them was serious and on 25 December, no settings had been found for the last six days. From 25 December to 1 January 1943 traffic was read quickly.
B-Dienst
The German Beobachtungsdienst (B-Dienst, Observation Service) of the Kriegsmarine Marinenachrichtendienst (MND, Naval Intelligence Service) had broken several Admiralty codes and cyphers by 1939, which were used to help Kriegsmarine ships elude British ships and provide opportunities for surprise attacks. From June to August 1940, six British submarines were sunk in the Skaggerak using information gleaned from British wireless signals. In 1941, B-Dienst read signals from the Commander-in-Chief, Western Approaches, informing convoys of areas patrolled by U-boats, enabling the submarines to move into "safe" zones. B-Dienst broke Combined Naval Cipher No. 3 in February 1942 and by March was reading up to 80 per cent of the traffic, which continued until 15 December 1942. By coincidence, the British lost access to the Shark cypher and had no information to send in Cypher No 3 which might compromise Ultra.
Prelude
The ships departed Liverpool on 18 December 1942 and comprised 50 merchant ships, in ballast or carrying trade goods. The convoy commodore was Vice Admiral (Retd.) Wion de Malpas Egerton in Empire Shackleton. The convoy sailed in twelve columns of three or four ships each. The convoy formation was five miles (8 km) wide and 1.5 miles (2.4 km) long. Convoy ON 154 was a slow convoy, made up of ships that could manage 8 kn (15 km/h; 9.2 mph) at best. Slow convoys were particularly vulnerable, as their speed was matched by the submerged speed of the U-boats and was just half their surface speed, thus making it easier for a wolfpack to form around it. In the North Atlantic were the U-boat wolfpacks Ungestum with 13 boats and Spitz with 11 boats, on patrol in the Mid-Atlantic gap, where Allied air cover was unable to reach. A third pack, Falke acted as a reserve but attacked Convoy HX 219 instead.
The ocean escort for Convoy ON 154 was the Royal Canadian Navy (RCN) Mid-Ocean Escort Force Group C-1, led by Lieutenant-Commander Guy Windeyer in the River-class destroyer HMCS St. Laurent. The group comprised the Flower-class corvettes HMCS Battleford, Chilliwack, Kenogami, Napanee, and Shediac. The Town-class destroyer HMS Burwell had mechanical defects, did not sail and was not replaced with another destroyer. RCN ships generally suffered from overwork compared to their Royal Navy equivalents, and were more likely to be un-modernized. Convoy ON 154 included the convoy rescue ship Toward, the oiler Scottish Heather and the French-crewed 2,456 GRT special service vessel HMS Fidelity. Fidelity was armed with four 4 in (100 mm) guns, four torpedo tubes and a defensive torpedo net. She carried the landing craft LCV-752 and LCV-754, two Kingfisher floatplanes and the Motor Torpedo Boat MTB 105.
Action
26/27 December
The winter of 1942–1943 turned out to be the worst in the Atlantic for thirty years. In November, convoys were routed further south than usual, which took them away from the air cover from northern bases, when Allied Anti-submarine warfare (ASW) aircraft were not grounded by the weather. Convoy ON 154 was routed south towards the Azores to avoid the winter storms and remained distant from escort support groups for longer than usual. U-662 reported the convoy on 26 December. That night U-356 torpedoed the leading ships from two of the starboard columns. Empire Union was hit at 01:40, Melrose Abbey was hit ten minutes later. Both British freighters sank at about 02:30. Toward rescued 63 survivors from the first ship and 47 from the second. In a second attack, U-356 torpedoed the Dutch freighter Soekaboemi at 04:10 and the British freighter King Edward at 04:15. King Edward sank within three minutes. U-356 was detected by the escorts and was sunk with no survivors following depth charge attacks by St. Laurent, Chilliwack, Battleford and Napanee. At dawn, Toward rescued 25 men from King Edward and assisted Napanee, recovering all but one of Soekaboemi's crew, the ship remaining afloat when abandoned at 07:30.
27/28 December
U-225 began stalking Scottish Heather as she refuelled some of the escorts 15 nmi (28 km; 17 mi) astern of the convoy on the afternoon of 27 December. U-225 was twice driven off by Chilliwack before hitting the oiler with a torpedo in a third approach at 20:40. The ship was temporarily abandoned but the second mate re-boarded her with ten men and sailed the ship out of the danger zone. At dawn he returned and pattern-searched for lifeboats. The oiler returned to England independently after recovering all of her crew.
28/29 December
U-260 began shadowing the convoy on the morning of 28 December and directed 18 U-boats to the convoy. Fidelity attempted to launch a Kingfisher but it capsized and sank at 19:15. While St. Laurent rescued the Kingfisher crew, a coordinated night attack began with U-boats entering the starboard side of the convoy at 19:58. U-591 torpedoed the Norwegian freighter Norse King at 20:00. U-225 torpedoed the British freighters Melmore Head at 20:03 and Ville de Rouen at 20:05. U-260 torpedoed the British freighter Empire Wagtail at 20:45. As Empire Wagtail disintegrated in an explosion that claimed all of her crew, Fidelity reported a main engine failure and Shediac was sent to assist her two miles (3.2 km) astern of the convoy.
U-boats then entered the port side of the convoy. U-406 torpedoed the British freighters Lynton Grange at 21:20, Zarian at 21:23, and Baron Cochrane at 21:24. U-662 hit the damaged Ville de Rouen again at 22:10 and U-225 torpedoed the convoy commodore's freighter Empire Shackleton at 22:15 and the Belgian freighter President Francoui at 22:30. Disabled ships were also being attacked astern of the convoy. Baron Cochrane was sunk at 21:50 by U-123 and U-628 sank Lynton Grange a few minutes later. The crews had abandoned both ships when they were hit earlier. U-123 and U-435 sank Empire Shackleton at 22:55. U-591 sank the abandoned Zarian just before midnight.
Shediac was ordered to leave Fidelity 30 miles (48 km) astern and rejoin the convoy while searching for survivors. Shediac rescued 35 survivors from Melmore Head and 71 from Ville de Rouen between 03:10 and 03:30 and 24 from Empire Shackleton at 05:30. Shediac rejoined the convoy at 13:00 short of fuel and with inadequate provisions for the number of survivors aboard. Two lifeboats abandoned the damaged President Francoui, but the remainder of the crew attempted to sail independently to the Azores. U-225 torpedoed the ship again at 06:30 and it was sunk at 09:30 by U-336. The damaged Norse King was similarly attempting to reach the Azores when she was sunk by U-435 at 15:07. There were no survivors. The convoy escort was reinforced by the M-class destroyers HMS Milne and Meteor at 14:00 on 29 December after the arriving destroyers rescued 42 survivors from Baron Cochrane at 07:00, 52 survivors from Lynton Grange at 07:20 and 49 survivors from Zarian at 08:15.
HMS Fidelity 29/30 December
Fidelity restarted main engines at 05:00 and declined the offer to dispatch a tug from Gibraltar. Speed was limited to two knots while streaming anti-torpedo nets when observed by Meteor and Milne at 05:30. U-615 found Fidelity while her main engines were again stopped for repairs between 10:15 and 11:00. U-615 identified Fidelity as a Q-ship and shadowed her cautiously. A reconnaissance flight by Fidelity's remaining Kingfisher observed two shadowing submarines and two of Empire Shackleton's lifeboats. Fidelity launched LCV-752 and LCV-754 to retrieve the lifeboats. Fidelity recovered the Kingfisher and the two landing craft with Empire Shackleton's survivors that afternoon and launched MTB-105 to conduct anti-submarine patrols through the night.
U-615 launched four torpedoes at Fidelity at about 20:00 but the anti-torpedo net protected the ship from damage. MTB-105 had engine trouble and lost contact with Fidelity at about 23:00. MTB-105 heard radio calls from Fidelity shortly after dawn but had inadequate battery power to respond. U-435 torpedoed Fidelity at 16:30 and was surprised by the size of the resulting explosion and by the large number of men subsequently seen floating in the water where the ship had sunk. MTB-105 rigged a makeshift sail to try and reach land. Fidelity had on board 369 people (274 crew, 51 Marines and 44 survivors from Empire Shackleton), all were lost at sea, including Egerton, the convoy commodore.
30 December
On 30 December British destroyer HMS Fame arrived, Commander Ralph Heathcote, the commander of B-6 Escort Group taking over,
Windeyer, exhausted by the ordeal and now seeing torpedoes at every turn, was put to bed.
Battleford, Shediac, Milne and Meteor were released on 30 December to refuel in the Azores, leaving only four escorts remaining and as many as twelve U-boats in contact with the convoy. Following the loss of the convoy commodore, the two fast ships with large passenger complements (Calgary and Advastun), were invited to escape if they found an opportunity. HMCS St. Francis and the V-class destroyer HMS Viceroy reinforced the convoy escort before nightfall on 30 December. B-Dienst warned BdU of the reinforcement of the convoy escorts and the U-boats were ordered to disengage, many to rendezvous with U-117 to the west of the Azores.
Shediac and Meteor ran out of fuel before reaching the Azores. Battleford towed Shediac the last 40 nmi (74 km; 46 mi) and Meteor was towed the last 5 nmi (9.3 km; 5.8 mi). Once refuelled, the four ships joined the search for survivors from Fidelity. On 1 January, Woodstock found and rescued the eight men aboard MTB-105, which included the two aircrew from the Kingfisher but aside from the two-man Kingfisher crew rescued earlier by St. Laurent, there were no other survivors from Fidelity's crew of 325 and the men rescued from Empire Shackleton. Prescott also saved 26 men from President Francoui whose Chief Officer, Lagay, reported that the conduct of some of the survivors had been less than admirable, malingering, insubordination and violence being reported. Scottish Heather reached the Clyde on 2 January and the remainder of the convoy reached New York City on 12 January 1943.