The origin of the Hecht began with the salvage of the two British X class submarines HMS X6 and X7 which had been sunk during Operation Source, an attempt to sink the German battleship Tirpitz.

It dispensed with a dual diesel/electric propulsion system, relying instead solely on electrical power in the form of a 12 hp AEG torpedo motor, on the basis that since it would operate submerged there was no need for a diesel engine.

Since the boat would need to be able to pass through anti-submarine nets and similar obstacles, it was designed without hydroplanes or fins, her trim being controlled with adjustable weights within the pressure hull.

Even though Hecht had been designed to transport an explosive charge, Karl Dönitz insisted that a torpedo be carried so that attacks could be carried out on vessels in coastal waters and Hecht was designed to be armed either with an underslung torpedo or an underslung mine, and a limpet mine in the nose.

A total of 53 Hechts were built between May and August 1944, but their unsatisfactory performance meant they never saw action, and were mostly used for training Seehund crews.