U-722 was a Type VIIC, the workhorse design of the Kriegsmarine. Her keel was laid down on 21 December 1942 at the yard of H. C. Stülcken Sohn in Hamburg, an old shipbuilder on the Elbe that had been turned over to U-boat work. She was launched on 21 September 1943 and commissioned on 15 December 1943 under Leutnant zur See Hans-Heinrich Reimers. By that point in the war the loss rate among German submarines had become catastrophic. The men who walked onto her deck on commissioning day in Hamburg harbour already knew, statistically, that most of them would not see Germany again.

She was 67 metres long, displaced 769 tonnes on the surface and 871 submerged, and could dive to 230 metres before the pressure hull began to threaten failure. Two Germaniawerft diesel engines drove her at 17.7 knots on the surface; submerged, AEG electric motors took over and pushed her along at no more than 7.6 knots, draining batteries that needed hours to recharge. She carried fourteen torpedoes, an 8.8 cm deck gun, and twin anti-aircraft guns. The crew lived for weeks on end in a steel tube barely six metres wide, sleeping in shifts and rarely seeing the sun. The Type VIIC was a fine boat for the war the Germans expected; by 1943 it was no longer a fine boat for the war they were fighting.

U-722's operational career was short and largely uneventful. She trained with the 31st U-boat Flotilla through the spring and summer of 1944, then joined the 1st Flotilla on active service on 1 August 1944. When the Allies pushed the Germans out of the French Atlantic bases, she transferred to the 11th Flotilla in Norway. In three war patrols she sank one merchant ship. She joined no wolfpack. By the spring of 1945 the U-boat campaign had collapsed under Allied air patrols, escort carriers, and improving radar; sailing west out of Norway was now closer to a death sentence than a mission.

The frigates HMS Fitzroy, HMS Redmill and HMS Byron of the British 21st Escort Group caught her on 27 March, north of the Hebrides, hunting her with ASDIC sonar and dropping depth charges in patterns that crushed her hull. The Atlantic here is deep and the records of those final hours come only from the surface ships. Sound contact, weapons released, debris, oil. Nothing more came up. U-722 was reported sunk in roughly the position 57.15°N, 6.92°W, west of the Isle of Skye. The war ended on 8 May 1945.

What is easy to forget when reading service histories of warships is that the boats were full of people. U-722's complement was between forty-four and sixty young men, conscripted, volunteered, trained, deployed. Most were in their twenties. Their families in Hamburg, Bremen, Kiel and elsewhere learned in the last weeks of a lost war that they would not be coming home. The cold sea west of Skye holds them still. From the air now, the surface looks ordinary, grey-green with the long Atlantic swell, the Hebrides rising in the east. Beneath it, somewhere, lies a steel tube and the men who died inside it.