|Ordered||20 Jan 1941|
|Laid down||3 Dec 1941||Danziger Werft AG, Danzig (werk 121)|
|Launched||18 Aug 1942|
|Commissioned||16 Dec 1942||Oblt. Hans-Jürgen Reese|
|Successes||No ships sunk or damaged|
Missing since 20 Oct, 1943 in the North Atlantic.
No explanation exists for its loss. 49 dead (all hands lost). (Axel Niestlé, January 1996).
The boat reported for the last time from approximate position 48.00N, 21.00W while enroute to its operational area of Newfoundland.
Previously recorded fate
- Sunk 26 Oct, 1943 in the North Atlantic, in postion 50.49N, 41.01W, by depth charges from a Canadian Liberator aircraft (RCAF Sqdn. 10/A). (Postwar assessment)
Notes. This attack was in fact against U-91 inflicting no damage.
Attacks on this boat and other events
3 Jul 1943
A Fido homing torpedo launched from a Canadian B 24 Liberator (Sqdn 10/B) killed two men and wounded another. The boat was severely damaged but managed to reach base at Lorient on on 16 July. [Bootsmann Heinz Grosser, Matrosengefreiter Willi Noeske]
1 recorded attack 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-420 did not suffer any casualties (we know of) until the time of her loss.