Type VIIC  
Laid down 24 Jul, 1942 Blohm & Voss, Hamburg
Commissioned 6 May, 1943 Oblt. Hans Leilich
Commanders 05.43 - 03.45
03.45 - 05.45
Kptlt. Hans Leilich
Oblt. Heinz Schäffer
Career 1 patrol 6 May, 1943 - 30 Sep, 1943  5. Flottille (training)
1 Oct, 1943 - 28 Feb, 1945  21. Flottille (school boat)
1 Mar, 1945 - 8 May, 1945  31. Flottille (training)
Successes No successes

Interned at Mar del Plata, Argentina on 17 August, 1945 after a 66-day submerged trip from Norway.

Surrendered to USA in Boston on 13 Nov, 1945. She was torpedoed off Massachusetts on 13 Nov, 1946 during torpedo trials by USS Atule.

Surrender in Argentina in August, 1945

The boat left Kristiansand, Norway on 2 May, 1945 for a combat patrol in the English Channel. When Germany surrendered a few days later the boat was outbound in Norwegian waters. After deciding to head for Argentina Schäffer gave the married men on board the chance to go to shore. Roughly a third of the crew, 16 men, opted for the shore and were put on land on 10 May near Holsenöy in dinghies. They all ended up in British hands. U-977 then sailed for Argentina; from May 10 to July 14 the voyage was a 66-day continuous submerged Schnorchel run, the second longest in the war (after U-978's 68 days).

The journey was extremely difficult for the crew and many were apparently on the edge of a nervous breakdown. The boat stopped in Cape Verde Islands for a short swim break and then headed south on the surface using one diesel. Crossing the equator on July 23 she arrived in Mar del Plata, Argentina on 17 August for a total patrol length of 108 days.

The commander, Heinz Schäffer, published a book in 1952 called U-boat 977 about his journey.

Men lost from U-boats
Unlike many other U-boats, which during their service lost men due to accidents and various other causes, U-977 did not suffer any casualties (we know of) until the time of her loss.