Battle of the Atlantic, WW2, RCN, Canadian Navy, Chaudiere, U-boats

HMCS Chaudiere (Navy Photos, click to enlarge ), ex-Royal Navy H-class destroyer HMS Hero. The greatly-expanded Royal Canadian Navy played a major role in the Battle of the Atlantic, and accounted for some 23 German U-boats.

1943

JANUARY 1943

Battle of the Atlantic - Severe weather and evasive convoy routing kept losses down in January 1943. However, south of the Azores, out of range of air cover, Trinidad/Gibraltar tanker convoy TM1 lost seven out of nine ships to U-boats.

Monthly Loss Summary, including Russian Convoys
- 30 British, Allied and neutral ships of 189,000 tons in the Atlantic from all causes
- 4 U-boats including 1 by RAF in North Atlantic; 2 by US aircraft off Brazil; 1 by unknown causes

PROSPECTS FOR ALLIED VICTORY - The Russians gained a famous victory with the German surrender at Stalingrad in January 1943. Taken with the October 1942 British Battle of El Alamein and June 1942 American Battle of Midway, the three Allied successes are usually considered as marking the turning point in the 40 month old war against the Axis powers. The Battle for Guadalcanal, ending as it did Japanese hopes of controlling the South West Pacific should also be added to this roll-call of victory. However, more than 30 months of struggle and bloodshed had to be endured before victory was certain. Even then, one Battle was not over until the very end - the Battle of the Atlantic, although it did peak over the next four months.

FEBRUARY 1943

Monthly Loss Summary, including Russian Convoys
- 50 British, Allied and neutral ships of 310,000 tons in the Atlantic from all causes, 1 corvette
- 15 U-boats including 5 by RAF in North Atlantic and off Portugal and Gibraltar; 2 by RAF and US aircraft on Bay of Biscay patrols; 1 by US Navy in North Atlantic.

MARCH 1943

Battle of the Atlantic - Throughout the war a large proportion of the losses due to U-boats were among independently routed merchantmen and stragglers from convoys, but in March 1943 the Germans came close to overwhelming well escorted convoys. Between the 7th and 11th, slow convoy SC121 lost 13 ships. Worse was to come between the 16th and 20th in the largest convoy battle of the war - around HX229 and SC122. Over 40 U-boats were deployed against the two as they slowly coalesced in the mid-Atlantic air gap until there were 100 ships plus their escorts. Twenty U-boats took part in the attacks and sank 21 merchantmen before additional air and surface escorts finally drove them off. A RAF Sunderland accounted for the one U-boat destroyed. Again the German B-Service was responsible for providing Doenitz' packs with accurate convoy details and routeing. These losses took place at another turning point in the secret war around the Enigma codes. Early in the month the U-boats changed from three-rotor to the far more complex four-rotor 'Triton' code. Yet by month's end this had been broken by the men and women of Bletchley Park and their electromechanical computers. The Allies' tremendous advantage was restored.

This came at the same time as a number of other developments which together brought about a complete reversal in the war against the U-boats. (1) The first five Royal Navy support groups with modern radars, anti-submarine weapons and HF/DF were released for operation in the North Atlantic. Two were built around Home Fleet destroyers, two around Western Approaches escorts, including Capt Walker's 2nd Escort Group, and one with escort carrier "Biter". Escort carriers "Archer" and the American "Bogue" were also ready for action, but "Dasher" was unfortunately lost in UK waters. Nevertheless, the mid-Atlantic air gap was about to be finally closed. (2) Another major breakthrough was again in the air war. Aircraft were being fitted with the 10cm wavelength radar which was undetectable by U-boat Metox receivers. The new radar and the Leigh light made a powerful weapon against surfaced submarines, especially as they tried to break out through the Bay of Biscay air patrols. (3) More VLR aircraft were also joining Coastal Command to further extend the Allies grip on the convoy routes throughout their length.

Monthly Loss Summary
- 90 British, Allied and neutral ships of 538,000 tons in the Atlantic from all causes, 1 destroyer
- 12 U-boats including 4 by the RAF in North Atlantic; 1 by RAF Bay of Biscay patrols; 1 by US aircraft off Barbados; 2 by US forces off the Azores and Canary Islands; 1 by unknown causes

APRIL 1943

Battle of the Atlantic - U-boat strength was up to 425 with 240 boats operational, and over half of them on passage through or on patrol throughout the North Atlantic. However, there was somewhat of a lull until the end of the month with the start of the ONS5 battle. A group also operated once again in the weakly defended Sierra Leone area. In just one night "U-515" sank seven of the 18 ships in Takoradi/Sierra Leone convoy TS37. Changes were again made in the Allies' responsibility for the North Atlantic routes. As agreed at the March 1943 Atlantic Convoy Conference in Washington: (1) Royal Canadian Navy was to exercise full control of the northerly routes west of the 47-00'W CHOP line - approximately south of Greenland. (2) Royal Navy took over to the east of 47-00'W. (3) US Navy looked after the southerly convoys,and also the CU/UC tanker routes between the West lndies and UK. With these organisational changes, the far more effective convoy Escort Groups, and the developments described in March, the scene was set for the decisive convoy battles of May 1943.

Monthly Loss Summary
- 40 British, Allied and neutral ships of 242,000 tons in the Atlantic from all causes, 1 destroyer and 1 submarine
- 14 German and 1 Italian U-boats including 3 by the RAF in the North Atlantic and off the Canaries; 1 by RAF Bay of Biscay patrol; 1 by RAF-laid mine in the Bay of Biscay; 1 by RAAF north of the Faeroes; 3 to US forces in the North and South Atlantic, including the one Italian

MAY 1943

Victory of the Escorts - The May 1943 Convoy Battles were a major victory. Summary statistics for the main battles are:

15 convoys totalling 622 merchantmen, protected by seven British B and five Canadian C convoy groups, six British and one US supporting Escort Group, three escort carriers

Well over 70 German U-boats at sea; 23 sunk

11 convoys were unscathed, four convoys lose 19 ships - a loss rate of 3 percent

Without the heavy losses of ONS5, loss rate was 1 percent

Without the U-boats sunk in attacks on OSN5, 16 U-boats were lost in exchange for 6 merchantmen

Monthly Loss Summary
- 40 British, Allied and neutral ships of 204,000 tons in the Atlantic from all causes
- 37 German and 1 Italian U-boats. In addition to those lost in or around the convoy battles: 3 by RAF in North Atlantic; 6 by RAF and RAAF Bay of Biscay patrols; 4 by US forces in the North Atlantic, off Florida and Brazil; 2 by collision in the North Atlantic

DEFENCE OF TRADE - January 1942 to May 1943

Total Losses = 2,029 British, Allied and neutral ships of 9,792,000 tons ( 576,000 tons per month)

By Location

Location

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

North Atlantic

1,234

6,808,000 tons

South Atlantic

97

611,000 tons

UK waters

105

248,000 tons

Mediterranean

129

598,000 tons

Indian Ocean

230

873,000 tons

Pacific Ocean

234

654,000 tons

By Cause

Causes * in order of tonnage sunk
(1. 4. ... - Order when weapon first introduced)

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

1. Submarines

1,474

8,048,000 tons

4. Aircraft

169

814,000 tons

5. Other causes

228

348,000 tons

6. Raiders

31

202,000 tons

2. Mines

71

172,000 tons

3. Warships

31

130,000 tons

7. Coastal forces

25

78,000 tons

JUNE 1943

Battle of the Atlantic - The Royal Navy had finally changed the convoy codes and made them secure against the work of the German B-Service. In contrast, the British 'Ultra' work was fully integrated into the Admiralty U-boat Tracking Room, and an almost complete picture of German Navy and U-boat operations was available. Not one North Atlantic convoy was attacked during the month although U-boats were operating around the Azores. As Allied air and sea forces grew in strength and effectiveness, especially through the use of 10cm radar and 'Ultra', Adm Doenitz sought other ways to regain the initiative. This he was never able to do, although right through until the last day of the war, the Allies coulld not relax their efforts, and continually introduce new detection systems, weapons and tactics. Against numerous, well-trained and effectively used escorts, the day of the conventional submarine was drawing to a close. The Germans placed much faith in the Walther hydrogen peroxide boat now under development, which with its long underwater endurance and high speed, would have proved a formidable foe. It did not get beyond the experimental stage by war's end. An interim step on the road towards the 'true' submarine started at the end of 1943 with the design and building of Type XXI ocean and XXIII coastal boats. Using the streamlined hull of the Walther and high capacity batteries, their underwater speed made them faster than most escorts. Fortunately for the Allies they did not enter service in numbers until too late in 1945.

For now the Germans had to rely on the U-boats currently in service and building. Total numbers stayed at around the 400 mark for the remainder of the war, in spite of a 40 boat per month construction programme, and various steps were taken to improve their offensive and defensive capability. Apart from extra AA armament, the Gnat acoustic torpedo was introduced specifically to combat the convoy escorts. Its first test came in September 1943. Before then in July, the schnorkel, a Dutch development that allowed batteries to be recharged at periscope depth, started trials. It did not enter general service until mid-1944, but then went quite some way to nullifying the radar of the air escorts and patrols. Even now the German Navy was unaware that the Allies were using short wavelength radar, but when they did, early in 1944, an effective detector was shortly introduced.

Monthly Loss Summary
- 7 British, Allied and neutral ships of 30,000 tons in the Atlantic from all causes,
- 16 German and 1 Italian U-boats including 4 by US and RAF aircraft off Iceland and the Strait of Gibraltar, and the Italian boat in the North Atlantic; 3 by the US Navy, one off the east coast of America and two to escort carrier "Bogue" off the Azores; 1 by French aircraft off Dakar.

JULY 1943

Monthly Loss Summary
- 29 ships British, Allied and neutral ships of 188,000 tons in the Atlantic from all causes
- 34 U-boats including 3 by RAF and US aircraft off Portugal; 7 by US escort carrier groups south and west of the Azores (6 of these by aircraft from "Core", "Santee" or "Bogue"); 9 by US aircraft in the Caribbean and off Brazil.

AUGUST 1943

Monthly Loss Summary
- 4 British, Allied and neutral ships of 25,000 tons, 1 escort
- 20 U-boats including 6 by aircraft of US escort carriers Card and Core off the Azores and in mid-Atlantic; 2 by US aircraft in the Caribbean area; 1 by RAF and French aircraft off Dakar; 1 by US forces in the South Atlantic

SEPTEMBER 1943

Assault on the Escorts: Convoys ONS18 and ON202 - The German wolf-packs returned to the North Atlantic armed with Gnat acoustic torpedoes to home on and disable the escorts so they could reach the merchantmen. In attacks on these convoys, three U-boats were lost in exchange for six merchant ships and escorts "LAGAN", Canadian "ST CROIX", "POLYANTHUS" and "ITCHEN". Fortunately the Allies had anticipated the introduction of acoustic torpedoes and soon put into service 'Foxer' noisemakers, towed astern to attract the Gnat away from the vessel. The U-boats did not repeat their successes.

Monthly Loss Summary
- 11 ships of 54,000 tons and 4 escorts
- 6 U-boats including one each by RAF and RCAF Bay of Biscay patrols, and one by US aircraft off Brazil

OCTOBER 1943

Battle of the Atlantic - After lengthy negotiations ending in August 1943, Portugal granted the Allies the right to establish air and sea bases in the Azores as from October. This greatly extended the Allies' ability to cover the central Atlantic and the convoy routes between Britain and North and West Africa; also between North America and the Mediterranean.

Monthly Loss Summary
- 13 ships of 61,000 tons and 1 destroyer
- 23 U-boats including 4 by RAF and US aircraft in North Atlantic and off Portugal; 6 by US escort carriers Card, Core and Block Island off the Azores and in mid-Atlantic.

NOVEMBER 1943

Monthly Loss Summary
- 7 ships of 28,000 tons and 1 US destroyer off the Azores
- 16 U-boats including 2 by RAF and US Bay of Biscay air patrols; 2 by RAF in North Atlantic and off the Azores; 3 by US forces in mid-Atlantic and off Ascension in the South Atlantic.

DECEMBER 1943

Monthly Loss Summary, including Russian Convoys
- 7 ships of 48,000 tons and 2 destroyers including one US in the North Atlantic
- 1 German battlecruiser ("Scharnhorst" in the Battle of North Cape) and 5 U-boats including 1 by RAF Bay of Biscay patrol; 3 by US Navy in Azores and Madeira areas; 1 scuttled after storm damage in mid-Atlantic

1944

JANUARY 1944

Battle of the Atlantic - Over the next five months U-boat losses were so heavy that by May 1944, North Atlantic operations had virtually ceased. In this period only 25 merchant ships were lost in the North and South Atlantic at a cost of 77 U-boats from all causes. At the same time the Allies were not so successful against them as they passed through the Bay of Biscay from French bases, the Northern Transit Area from Norway, and direct from Germany. Now equipped with 10cm radar detectors they only lost five of their number in the Bay, but in mid-May were badly hit by RAF Coastal Command off Norway. By then the whole complexion of the U-boat war near the shores of Europe changed with the invasion of Normandy.

Monthly Loss Summary, including Russian Convoys
- 5 British, Allied and neutral ships of 36,000 tons in the Atlantic from all causes, 2 destroyers including one US off New York, and 1 frigate
- 14 U-boats including 2 by RAF and RAAF Bay of Biscay patrols; 1 by RAF-laid mine in Bay of Biscay; 1 by US escort carrier Guadalcanal off the Azores

FEBRUARY 1944

Monthly Loss Summary, including Russian Convoys
- 2 British, Allied and neutral ships of 12,000 tons in the Atlantic from all causes, 1 destroyer and 1 sloop
- 15 U-boats including 2 by RAF to the west of Scotland; 1 by US Navy aircraft off Ascension Island

MARCH 1944

Battle of the Atlantic - To make more efficient use of available tonnage, trans-Atlantic convoys were now designated Fast, Medium or Slow. All this time great numbers of US servicemen were being carried across to Britain in preparation for the invasion of Europe, many by the fast, unescorted liners "Queen Elizabeth" and "Queen Mary" each carrying 15,000 men every trip.

Monthly Loss Summary, including Russian Convoys
- 8 British, Allied and neutral ships of 41,000 tons in the Atlantic from all causes, 2 escorts and 1 US destroyer off Iceland
- 17 U-boats including 1 by RCAF off Ireland; 4 by the aircraft and ships of USS Block Island off the Azores and Cape Verde Islands; 1 by unknown causes in the North Atlantic; 1 by SAAF off South Africa

APRIL 1944

Monthly Loss Summary, including Russian Convoys
- 7 British, Allied and neutral ships of 48,000 tons in the Atlantic from all causes
- 16 U-boats including 2 by RAF in North Atlantic; 1 by RAF Bay of Biscay patrol; 6 by US Navy forces off America, Madeira, Cap Verde Islands and in North Atlantic.

MAY 1944

Battle of the Atlantic - RAF Coastal Command and one of its Norwegian squadrons were particularly successful between the 16th and 27th against the U-boats passing through the Northern Transit Area off south and west Norway. In the space of 12 days, "U-240", "U-241", "U-476", "U-675", "U-990" and "U-292" were sunk.

Monthly Loss Summary, including Russian Convoys
- 3 British, Allied and neutral ships of 17,000 tons in the Atlantic from all causes, 1 frigate and 1 US escort carrier
- 15 U-boats including 1 by RCAF Bay of Biscay patrol

DEFENCE OF TRADE - June 1943 to May 1944

Total Losses = 324 British, Allied and neutral ships of 1,733,000 tons (144,000 tons per month)

By Location

Location

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

North Atlantic 76 443,000 tons

South Atlantic

27 147,000 tons

UK waters

23

31,000 tons

Mediterranean

105

550,000 tons

Indian Ocean

87

532,000 tons

Pacific Ocean

6

30,000 tons

By Cause

Causes* in order of tonnage sunk
(1. 4. ... - Order when weapon first introduced)

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

1. Submarines

216

1,219,000 tons

4. Aircraft

64

378,000 tons

2. Mines

19

55,000 tons

6. Raiders

4

35,000 tons

5. Other causes

9

20,000 tons

7. Coastal forces

11

18,000 tons

3. Warships

1

8,000 tons

JUNE 1944

Battle of the Atlantic - U-boats passing through the Bay of Biscay were the target for aircraft covering the Normandy invasion, and also continued to suffer badly at the hands of the aircraft of the Northern Transit Area patrol. Throughout the month, seven were sunk and one severely damaged by RAF, RCAF and Norwegian aircraft. In the case of "U-1225" to the northwest of Bergen on the 24th, the attacking Canadian Canso (or Catalina) was badly hit and crashed but not before sinking her. + Flt Lt David Hornell RCAF, pilot of the Canso of No 162 Squadron, Coastal Command, was posthumously awarded the Victoria Cross.

Monthly Loss Summary
- 3 British, Allied and neutral ships of 7,000 tons in the Atlantic from all causes
- 13 U-boats excluding those sunk in Bay of Biscay

6th of June 1944 - Normandy Invasion: Operation 'Overlord'

JULY 1944

Monthly Loss Summary
- 4 British, Allied and neutral ships of 29,000 tons in the Atlantic from all causes
- 7 U-boats including one each by task groups of US escort carriers "Wake Island", "Croatan" and "Card" off the Canaries, Madeira and Nova Scotia respectively

AUGUST 1944

Monthly Loss Summary, including Russian Convoys
- 1 ship of 6,000 tons, 1 escort carrier, 2 escorts, 1 US destroyer escort off Azores
- 3 U-boats including 1 by aircraft of escort carrier "Bogue" off Newfoundland

SEPTEMBER 1944

U-boat Inshore Campaign - With the start of the British Isles Inshore Campaign, U-boats sunk off Norway and in the Western Approaches as well as the Bay of Biscay are no longer included in the Battle of the Atlantic, but in the European theatre. The same applies to the Royal Navy and German surface warships lost. See Western Europe - Normandy to Berlin

Monthly Loss Summary, including Russian Convoys
- 3 British, Allied and neutral ships of 17,000 tons in the Atlantic from all causes, 1 US destroyer in a hurricane off Bahamas
- 7 U-boats including 1 cause unknown and 1 mined off Iceland; 1 by RAF off the Azores; 1 by US Navy off Cape Verde Islands; 1 by US aircraft in South Atlantic

OCTOBER 1944

Monthly Loss Summary
- For the first time since September 1939, no merchant ships were lost throughout the length and breadth of the North and South Atlantic in October 1944
- 1 U-boat in the North Atlantic due to schnorkel defect.

NOVEMBER 1944

Monthly Loss Summary
- 3 British, Allied and neutral ships of 8,000 tons in the Atlantic from all causes, 1 corvette

DECEMBER 1944

Monthly Loss Summary, including Russian Convoys
- 1 merchant ship of 5,000 tons in the Atlantic
- 3 German U-boats

1945

JANUARY 1945

Monthly Loss Summary
- 5 British, Allied and neutral ships of 29,000 tons in the Atlantic from all causes
- 1 U-boat by USN in mid-Atlantic

FEBRUARY 1945

Monthly Loss Summary, including Russian Convoys
- 6 British, Allied and neutral ships of 39,000 tons in UK waters, 3 escorts
- 3 U-boats including 1 by US and French escorts off Morocco

MARCH 1945

Monthly Loss Summary, including Russian convoys
- 4 British, Allied and neutral ships of 27,000 tons in the Atlantic from all causes, 1 sloop
- 1 U-boat by USN off Nova Scotia

APRIL 1945

Monthly Loss Summary, including Russian Convoys
- 5 British, Allied and neutral ships of 32,000 tons in the Atlantic from all causes, 1 frigate and 1 US destroyer off the Azores
- 9 U-boats including 7 by USN off east coast of USA, off the Azores and in mid-Atlantic

MAY 1945

Battle of the Atlantic - Conclusion - Just 68 months before, northwest of the British Isles liner "Athenia" was torpedoed by "U-30" and 11 days later "U-39" sunk by Royal Navy destroyers. Since then, tens of thousands of lives, thousands of ships and hundreds of U-boats had been lost in the battle to sustain Britain as the base without which the liberation of Europe would had been impossible. As the United States took over from Britain the mantle of the world's most powerful navy, so the last merchantmen and U-boats of the Battle of the Atlantic went to the bottom in American waters and involving American ships. 6th - "U-881" was sunk by the US Navy south of Newfoundland. On the same day, "U-853" torpedoed freighter "Black Point" off New York, was hunted down and sunk by US destroyer escort "Atherton" and frigate "Moberley".

The cost of the Battle is usually measured in terms of the 2,400 merchantmen sunk in the North and South Atlantic. To this must be added one battlecruiser, three fleet and escort carriers, two cruisers and 47 destroyers and escorts of the Royal and Canadian Navies lost in the Atlantic, excluding the convoy routes to Russia. Also the warships lost by the United States and other Allied navies.

Monthly Loss Summary
- 1 merchant ship of 5,000 tons in the Atlantic
- 2 German U-boats

DEFENCE OF TRADE - June 1944 to May 1945

Total Losses = 210 British, Allied and neutral ships of 942,000 tons ( 78,000 tons per month)

By Location

Location

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

North Atlantic

31

177,000 tons

South Atlantic

5

28,000 tons

UK waters

135

500,000 tons

Mediterranean

5

7,000 tons

Indian Ocean

21

134,000 tons

Pacific Ocean

13

96,000 tons

By Cause

Causes* in order of tonnage sunk
(1. 4. ... - Order when weapon first introduced)

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

1. Submarines

120

629,000 tons

2. Mines

50

162,000 tons

4. Aircraft

14

96,000 tons

5. Other causes

15

28,000 tons

7. Coastal forces

11

27,000 tons

3. Warships

-

-

6. Raiders

-

-

TOTAL MERCHANT SHIP LOSSES - SEPTEMBER 1939 to AUGUST 1945

Summarised here in all its immensity is the losses in ships suffered by Britain, its Allies and neutral countries throughout the war. Of the grand totals that follow, Britain's losses amounted to around 50% of tonnage, with a similar percentage applying to sinkings in the North and South Atlantic. Both figures point to the critical importance of the Battle of the Atlantic and to the price Britain paid for keeping open the sea-lanes. In concentrating on losses, it should not be overlooked that taking the war as a whole, well over 99% of merchantmen reached their destination safely. On the other side of the balance sheet, more than 30,000 officers and men of the British Merchant Navy did not come home plus the many men of Allied and Neutral nations. Axis losses must have been comparable.

Total Losses = 5,150 British, Allied and neutral ships of 21,570,000 tons (300,000 tons per month)

By Location

Location

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

North Atlantic

2,232

11,900,000 tons

South Atlantic

174

1,024,000 tons

UK waters

1,431

3,768,000 tons

Mediterranean

413

1,740,000 tons

Indian Ocean

385

1,790,000 tons

Pacific Ocean

515

1,348,000 tons

By Cause

Causes* in order of tonnage sunk
(1. 4. ... - Order when weapon first introduced)

Number of British, Allied, neutral ships

Total Gross Registered Tonnage

1. Submarines

2,828

14,686,000 tons

4. Aircraft

820

2,890,000 tons

2. Mines

534

1,406,000 tons

5. Other causes

632

1,030,000 tons

6. Raiders

133

830,000 tons

3. Warships

104

498,000 tons

7. Coastal forces

99

230,000 tons