U-593 was a new boat, but damaged and making for St Nazaire. It was the first operational command for Kapitänleutnant Gerd Kelbling. On 2 March it had left Kiel for war patrol around the northern coasts of the British isles. During the night of 9-10 March, U-593 had passed through the Shetland-Faeroes gap, during which she had been depth-charged by the escorts of a convoy, but had avoided any damage.


On 18 March, U-593 was in action again, with three destroyers, which together rained down a total of 136 depth-charges on her, causing sufficient damage for her to make a run for the base, with her electrical control system impaired, U-593 found it hard to steer under water, her hydroplanes and rudder now being worked slowly by hand. There were leaks in her high-pressure air system and outer hull was damaged, but nobody could tell how badly.

U-593 had been instructed by radio to make for St Nazaire at her best speed, following the course which brought her precisely to the position where she could now play a vital role, not realising how, in promoting the success of ‘Chariot’.

Kelbling, watching from the conning tower, wasn’t sure if the force was a friendly one. He couldn’t identify the three destroyers accompanying what he took to be MTBs. Thinking it most unlikely to be British, maybe Dutch or Norwegian ships taken into German service, continued moving east towards the coast, but keeping an eye on the distant warships.

Watching the progress towards him of the first destroyer, Kelbling was initially reassured by the sight of her German Ensign. U-593 kept moving away at his best speed of 12-13 knots. When the range had closed to six miles put up the appropriate recognition signal, a pyrotechnic device bursting into five silver stars. Kelbling’s became suspicious when the vessel did not reply. At a range of three and a half miles, he put up the signal again - prompting a response of five long flashes on Tynedale’s Aldis, a lucky guess on Tweedie’s part, as it was accepted practice in the German Navy to give long flashes of the lamp if it was not possible to return a recognition signal.

With Tynedale firing, the U-593 crash-dived. After the initial shock of seeing the White Ensign run up, Kelbling decided to mount an attack, using his stern torpedo tube. He was confident of taking on this single ship and quickly produced figures for firing his torpedo. The torpedo refused to fire, its tube having been damaged in an earlier attack.

After first rising to the surface, the U-boat began to go down, slowly and then very fast, at an angle of 45&Mac251; degrees. Kelbling brought her out of the dive at 150 metres and found a trim. Steering was difficult, but decided to stay down, rigging the boat for silent routine and travelling at a little more than one knot through the water. Above could be heard a confusion of sounds, which died away to silence.

At 1400, Kelbling judged it safe to surface. This time he radioed to Group Command West the sighting report. He stated that he had observed ‘three destroyers and ten MTBs at 0620 hours, in position 46&Mac251; 52’ North by 5&Mac251; 48’ West, and then went on to give their course as West, thinking they must have been a minelaying force withdrawing upon completion of a night’s work off the French Coast.

The ‘Chariot’ force was done a very great favour of being reported leaving, and not approaching its target. The direct result of Kelbling’s report was that the five destroyers of Schmidt’s flotilla, which might have been in a position to affect the outcome of the raid, were instead patrolling the usual approaches to the Loire. As they travelled seawards via the dredged Charpentiers Channel, they would pass U-593 sailing surfaced for the estuary. They would miss completely the elderly Campbeltown and forces sailing to the south of them, straight for the supposedly un-navigable estuary shallows.