I’m fairly familiar with the battle of the Atlantic and how German U-boats sank tons of merchant vessels en route to Britain. But it occurred to me that I have never asked and don’t know the answer to my question. So when the United States and Canada shipped hundreds of thousands of soldiers to the United Kingdom so that they could execute the invasion of Normandy. We’re any of these troop carriers sunk or even attacked at all? Or were their escorts far too many or too well armed for any U-boat to even attempt to attack the transports?
No troop transports carrying US troops were lost crossing the Atlantic, including after Normandy. Only 1 troopship was lost on an eastward crossing of the Atlantic during the war: the SS Nerissa, carrying Canadian troops. She was torpedoed late at night on 30th April 1941 by U-552, on her 40th wartime crossing of the Atlantic.
Troopships making the eastward crossing to the UK were well-protected, either by strong escorts or speed. Two notable troopships were RMS Queen Mary and RMS Queen Elizabeth, which made their crossings unescorted (until picking up escort on the approach to Britain), at high speed (30 knots or more). They could carry over 15,000 troops - a whole division - at a time (compared to about 2,200 passengers in peacetime). Queen Mary had some close calls: she was almost sunk by a giant wave, U-853 spotted her on the way to Britain in early 1944 but couldn't get into a firing position due to Queen Mary's speed, and she sliced through an escorting cruiser which blundered across her path as the ships zig-zagged.
One US troopship was sunk in the Atlantic: SS Dorchester was torpedoed on 3rd February 1943 by U-223, on the way from New York to Greenland. 675 of the 904 aboard died.
Eight US troopships were sunk in the European theatre. Five of them were sunk participating in Operation Torch. USS Thomas Stone (APA-29) was torpedoed by U-205 7th November, 150 miles short of Algiers, her destination (or possibly hit by an air-dropped torpedo). She was unable to steer or move under her own power, and was towed to Algiers where she was sunk in harbour by air attack 24th November. USS Joseph Hewes (AP 50) was sunk by U-173 11th November 1942, off Morocco; U-173 also sank a tanker and destroyer on the same occasion, but was sunk herself 16th November. USS Edward Rutledge (AP 52), USS Hugh Scott (AP 43) and USS Tasker H. Bliss (AP 42) were sunk by U-130 12th November 1942, also off Morocco. U-130 escaped to be sunk in the Atlantic in 1943. Troop and crew losses were low, since there were plenty of ships nearby to assist, and some of the ships had already landed their troops.
Much more deadly was the loss of the British transport HMT Rohna sailing from Oran (Algeria) to Alexandria with about 2,000 US troops aboard. She was hit by an air-launched Henschel Hs 293 guided glide-bomb 26th November 1943, killing 1,040 US troops and 224 crew.
USS Susan B. Anthony (AP-72) hit a mine early on 7th June 1944, taking part in the Normandy landings. All 2,689 people aboard were saved.
Also deadly was the loss of SS Léopoldville in the English Channel, sailing from Southampton and Cherbourg with reinforcements for the Battle of the Bulge. She was torpedoed by U-486 24th December 1944, killing 763 of the 2,223 soldiers of the US 66th Infantry Division aboard, and 45 crew.
Not strictly a troopship was SS Paul Hamilton, carrying supplies - including munitions - and 471 personnel to Italy for the US 485th Bombardment Group. She was hit by an air-dropped torpedo on 20 April 1944 and exploded:
killing all aboard.
The US also lost troopships in the Pacific theatre, and other nations lost troopships. The Japanese suffered badly, losing about 50,000 troops in their 20 deadliest troopship losses.
