It had a fully streamlined outer casing and apart from the relatively small conning tower and a fairing which housed the Diesel exhaust silencer, it had an uncluttered upper deck. In line with Walter's design practice, there were no forward hydroplanes, although these were added later. The submarine was propelled by a single three-bladed propeller and steered by a single rudder. As with the Type XXI, the lower section of the figure-of-eight hull was used to house a large 62-cell battery. In order to allow the boat to be transported by rail, the hull sections had to be limited in size to fit the standard loading gauge. For transportation, the hull was broken into four sections and the bridge was removed. Due to the space restrictions, the forward bow section had to be made as short as possible, which meant that only two torpedo tubes could be fitted and no reload torpedoes could be carried. The torpedoes were loaded by ballasting the submarine down at the stern so that the bow lifted clear of the water and the torpedoes could be loaded directly into their tubes from a barge. The Type XXIII proved to have excellent handling characteristics, and was highly maneuverable both on the surface and underwater. Its crash dive time was 9 seconds, and its maximum diving depth was . Speed submerged was , while surfaced speed was . A submerged speed of could be attained while snorkeling. The first forty-nine boats ("U-2321" to "U-2331", and "U-2334" to "U-2371") were ordered from Deutsche Werft, Hamburg, while two ("U-2332" and "U-2333") were ordered from Friedrich Krupp Germaniawerft's yard at Kiel. Twenty-nine further boats ("U-2372" to "U-2400") were ordered from Deutsche Werft's wartime occupied yards at Toulon, but the first nine of these were scrapped incomplete on the stocks and the remainder never commenced. Another sixty were ordered to be built by the company at other yards in occupied nations - thirty at Genoa ("U-2401" to "U-2430"), fifteen at Monfalcone ("U-2431" to "U-2445") and another fifteen at Mykolaiv and Linz ("U-2446" to "U-2460"), where a further forty ("U-2461" to "U-2500") were projected but never ordered. All of these were cancelled and never commenced.