This was a German naval minelaying operation by Kapitänleutnant Peter-Ottmar Grau’s U-601 in the Pechora Sea (14/26 July 1943).
The operation was part of a larger German undertaking for the laying of minefields by U-boats between 20 July and 10 August to strike at Soviet maritime movements in the Pechora Sea: these minefields were laid by U-625 off the Yugor Strait, U-601 off Belusha, U-629 in the western entrance of Pechora Bay and off Russky Savorot, U-586 to the east of Pechora Bay, U-212 and U-636 off Kolguyev, and U-639 in the Pechora Sea.
A convoy of 15 riverine vessels, which on 25 July departed the Pechora river estuary for the Ob river estuary, ran into these minefields and on 27 July lost the minesweeper T-904 off the Yugor Strait. On 30 July Oberleutnant Joachim Brünner’s U-703 sank a patrol vessel off the Kostin Strait. The motor minesweepers T-109 and T-110, delivered from the UK, were used to clear the ground mines. On 25 August the rescue ship Shkval was lost in the Yugor Strait.