List of all U-boats




Ordered10 Apr 1941
Laid down20 Jan 1942 Danziger Werft AG, Danzig (werk 122)
Launched24 Sep 1942
Commissioned13 Jan 1943Ltnt. Hans Kolbus
13 Jan 1943 - 29 Apr 1944  Oblt. Hans Kolbus
2 patrols
13 Jan 1943-31 Oct 1943  8. Flottille (training)
1 Nov 1943-31 Mar 1944  9. Flottille (active service)
1 Apr 1944-29 Apr 1944  29. Flottille (active service)
SuccessesNo ships sunk or damaged

Sunk at 1130hrs on 29 April 1944 at the Missiessy Quay in Toulon, France, in position 43.07N, 05.55E, by bombs during US air raid (15th AF).

The wreck was raised, taken to Missiessy Dock No. 2 and broken up in 1946.

Loss position

View the 2 war patrols

Wolfpack operations

U-421 operated with the following Wolfpacks during its career:
   Coronel (4 Dec 1943 - 8 Dec 1943)
   Coronel 1 (8 Dec 1943 - 14 Dec 1943)
   Coronel 2 (14 Dec 1943 - 17 Dec 1943)
   Föhr (18 Dec 1943 - 23 Dec 1943)
   Rügen 6 (23 Dec 1943 - 26 Dec 1943)
   Hela (28 Dec 1943 - 1 Jan 1944)

Attacks on this boat and other events

3 Jan 1944
00.16 hrs, Bay of Biscay, inbound: A British B-24 Liberator bomber (RAF Sqdn 224/C, pilot F/O Ethan Allen) strafed the boat and dropped eight depth charges in a Leigh Light attack. U-421 fought back with AA fire, then escaped by crash-diving. Damage minor. (Sources: Franks/Zimmerman)

2 Mar 1944
03.09 hrs, off Cape St. Vincent, Portugal: a British Wellington Mk XIV bomber (RAF Sqdn 179, pilot S/L R.G. Knott) located U-421 on radar and attacked using the Leigh Light, but the nose turret guns jammed after 40 rounds. Flak then knocked out the starboard engine, causing the six depth charges to miss, and another AA hit in the bomb bay disabled the radar. The crew had to jettison all superfluous equipment, including the damaged radar, to keep flying on one engine, and reached base after three hours. (Sources: Franks/Zimmerman)

2 recorded attacks on this boat.

Men lost from U-boats

Unlike many other U-boats, which during their service lost men due to accidents and various other causes, U-421 did not suffer any casualties (we know of) until the time of her loss.

U-boat Emblems

We have 1 emblem entry for this boat. See the emblem page for this boat or view emblems individually below.

Giant standing on Earth

Media links

German U-Boat Losses During World War II

Niestle, Axel

U-Boat Operations of the Second World War - Vol 1

Wynn, Kenneth

Hitler's U-boat War, Vol II

Blair, Clay

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