# Convoy RS 3

Convoy RS 3 was a South Atlantic convoy from 22–31 March 1943 between Gibraltar and Freetown in Sierra Leone. The convoy was part of the Battle of the Atlantic in the Second World War. The convoy lost its three biggest ships to U-boat attacks.
The three ships lost on Convoy RS 3 contributed to the fact that in March 1943 most of the ships sunk by U-boats were being convoyed. As convoying was the main tactic against U-boats, this led to a temporary crisis in Allied shipping.

## Background
### Kriegsmarine

Wolfpack Unverzagt (Unshrinking) and Wolfpack Wohlgemut (Cheerful) were on the way to form patrol lines off the Azores to attack a UGS convoy (United States to Gibraltar Slow) a series of slow convoys run from the United States to Gibraltar beginning with Operation Torch (8–16 November 1942). The convoy had been revealed by B-Dienst a code-breaking department of the German Naval Intelligence Service (Marinenachrichtendienst [MND]). Before the expected convoy was spotted, U-130 found Convoy UGS 6 of 45 ships, protected by the US destroyers USS Wainwright, USS Trippe, USS Champlin, USS Mayrant, USS Rowan, USS Rhind and USS Hobby. Champlin detected the u-boat and sank it. With the sea so calm, it was difficult for the U-boats to close on the convoy because the destroyers had centimetric radar but lacked High-frequency direction finding (huff-duff) to pinpoint U-boat wireless broadcasts.
Late on 13 March, U-172 sank a straggler SS Benjamin Harrison (7,191 GRT) and Wolfpack Tümmler joined the attack. That day, attacks by U-513, U-167 and U-172 were defeated by the convoy escorts and the U-boats were forced to retire. On 14 September U-106, U-167 and U-513 were driven off and U-515 was damaged by depth charging. On 15 March. U-159 and U-524 attacked the convoy submerged in daylight and U-524 sank Wyoming (8,062 GRT). On 16 March U-106 directed nine U-boats to the convoy but the escorts thwarted their attempts to attack the convoy and U-524, with U-172, made a simultaneous submerged attack in the evening. On the evening of 17 March U-167 torpedoed Molly Pitcher (7,200 GRT) which was sunk later by U-521.
On the next day, the convoy received air cover; U-524 maintained contact but was unable to attack and the attack on the convoy was terminated. U-524 was caught on the surface and sunk by the depth-charges of a B-24 bomber from the 2nd Antisubmarine Squadron on 22 March. Karl Dönitz the commander of U-boats (Befehlshaber der U-Boote, BdU) sent the remaining seven U-boats to form a cordon from the west to the south-east of the Canary Islands to attack another UGS convoy No UGS convoys were found and BdU moved the U-boats into the area between the African coast and the islands, along with U-123 that was en route to Freetown in Sierra Leone with the name gruppe Seeräuber (Pirate) based on reports from B-Dienst.

### Allied air power

The US Navy had established Fleet Air Wing 15 at Naval Air Station Port Lyautey in Morocco, in January, with the patrol squadrons VPB-73 and VPB-92, each with twelve Catalina flying boats. In March the United States Army Air Forces (USAAF) 1st Antisubmarine Squadron and the 2nd Antisubmarine Squadron of the 2037th Antisubmarine Wing (Provisional) with twelve B-24 Liberator bombers each, joined the naval aircraft at Port Lyautey.

### Convoy RS 3

When Convoy RS 3 left Gibraltar for Freetown in Sierra Leone, it consisted of the merchant ships SS Lagosian, SS Moanda, MV Silverbeech, the cable layer Lady Denison-Pender, whose captain, Harold Milne, was the convoy commodore, the tugs HMS Alligator, HMS Crocodile, the Seagoing Tugs ST Empire Ace and ST Empire Oberon. Lady Denison-Pender was returning after laying a cable between Gibraltar and Casablanca for communications at the Casablanca Conference. The convoy was escorted by the Bridgewater-class sloop HMS Bridgewater and the Flower-class corvette HMS Burdock.

## Prelude

U-513 made contact with the convoy on 28 March between the Canary Islands and Dakar. The Allied commanders did not know that the convoy was in danger and on the morning of 28 March, the convoy escorts Bridgewater and Burdock were diverted to reinforce the escort of a northbound convoy, leaving Convoy RS 3 to aircraft anti-submarine patrols.

## Attacks on 28 March

Shortly after the escorts left, U-159 attacked and torpedoed the 5,414 GRT, SS Lagosian at 31°12'N, 15°43'W, with seven crew killed and 39 survivors. The ship broke amidships and sank within seven minutes. Eleven survivors were rescued by the tugboat Empire Denis. The convoy started zigzagging and tried to increase speed but the tugs could not keep up and speed was reduced to seven kn (13 km/h; 8.1 mph). At 15:00 U-172 torpedoed the 5,311 GRT, MV Silverbeech which exploded and sank at 25°20'N, 15°55'W with 62 killed and 7 survivors. As the ships were in shallow waters, the convoy commodore was not sure whether they should run into a protective coastal minefield or fight the U-boats. A few minutes later U-172 launched a salvo of four torpedoes that missed. As night fell at 20:00 the zigzagging was stopped.
U-172 caught up with the convoy and its first attack with one torpedo missed but then U-167 torpedoed MV Moanda (4,511 GRT) with a second attack, firing two torpedoes. The ship sank at 02:00 the next morning at 24°44'N, 16°48'W with 29 killed and 27 survivors. Aircraft on convoy patrol attacked the U-boats and U-67 was sent out of control by a depth-charge attack, descending to 750 ft (230 m) before the crew regained control. After surfacing the crew found that six torpedo containers on deck and much of the superstructure were missing. U-159 was forced by air attack 698 ft (213 m) below the surface before the crew got the boat back under control. U-172 stayed with U-67 whilst it was inspected and when it was judged capable of returning to base; its captain gave surplus fuel to U-515, which took over the patrol to Dakar instead of U-159 which was diverted to a quiet spot off the Azores. On 29 March the U-boats lost contact and the attack was abandoned on 30 March.

## Aftermath
### Casualties

The crew of Lagosian suffered seven killed of 46 men, 63 of the 69 crew members of Silverbeech were killed and the loss of Moanda cost 29 killed with 27 survivors.

### Subsequent operations

After gruppe Seeraüber was dissolved on 30 March, the U-boats operated individually off Freetown. U-124 attacked Convoy OS 45 on 2 April and sank two ships of 9,547 GRT but was then sunk by the 37th Escort Group. U-167 was attacked on 6 April by two Hudsons of 233 Squadron from Gibraltar and was scuttled after the crew disembarked, about fifty of the men getting ashore on Gran Canaria. An Italian U-boat, Giuseppe Finzi, sank two independently sailing ships of a total of 9,264 GRT. U-455 and U-117 planted mines off Casablanca on 10 and 11 April, that sank one ship and damaged two. The rest of the U-boats reached Freetown in early April.

## Allied order of battle
### Convoyed ships

Merchant ships :
| Ship | Year | Flag | GRT | Notes |
| HMS Alligator | 1941 | Royal Navy | 395 | Seagoing tug |
| HMS Crocodile | 1940 | Royal Navy | 395 | Seagoing tug |
| ST Empire Ace | 1942 | United Kingdom | 275 | Ministry of War Transport tug |
| ST Empire Oberon | 1943 | United Kingdom | 244 | Ministry of War Transport tug |
| SS Lady Denison-Pender | 1920 | United Kingdom | 1,984 | Cable layer |
| Lagosian | 1930 | United Kingdom | 5,412 | Sunk |
| Moanda | 1937 | Belgium | 4,621 | Sunk |
| MV Silverbeech | 1926 | United Kingdom | 5,319 | Sunk |

### Convoy escorts

Convoy escort :
| Name | Navy | Class | Notes |
| HMS Bridgewater | Royal Navy | Bridgewater-class sloop | |
| HMS Burdock | Royal Navy | Flower-class corvette | |

### U-boats

gruppe Seeraüber (25–30 March 1943) :
| Name | Flag | Class | Notes |
| U-67 | Kriegsmarine | Type IXC submarine | |
| U-123 | Kriegsmarine | Type IXB submarine | |
| U-159 | Kriegsmarine | Type IXC submarine | |
| U-167 | Kriegsmarine | Type IXC/40 submarine | |
| U-172 | Kriegsmarine | Type IXC submarine | |
| U-513 | Kriegsmarine | Type IXC submarine | |
| U-515 | Kriegsmarine | Type IXC submarine | |
| U-524 | Kriegsmarine | Type IXC submarine | Sunk 22 March |