 This class of U-boat did not carry a deck gun.Completed in September 1944, "U-2331" was undergoing a fast-track working-up period in the Baltic under her commander "Oberleutnant zur See" Hans-Walter Pahl under the observation of Klaus Vernier, a highly experienced U-boat commander and tactical expert.On 10 October, just 28 days after her completion, "U-2331" dived and failed to surface in the sea off the Hel Peninsula.