The submarines of the KD7 sub-class were medium-range attack submarines developed from the preceding KD6 sub-class. They displaced 1833LT surfaced and 2602LT submerged. The submarines were 105.5m (346.1feet) long, had a beam of 8.25m (27.07feet) and a draft of 4.6m (15.1feet). The boats had a diving depth of 80m (260feet) and a complement of 86 officers and crewmen.[1]
For surface running, the boats were powered by two 40000NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 900hp electric motor. They could reach 23kn on the surface and underwater. On the surface, the KD7s had a range of 8000nmi at ; submerged, they had a range of 50nmi at .[2]
The boats were armed with six internal 53.3cm (21inches) torpedo tubes, all in the bow. They carried one reload for each tube; a total of a dozen torpedoes. They were originally intended to be armed with two twin-gun mounts for the 25mm Type 96 anti-aircraft gun, but a 120mm deck gun for combat on the surface was substituted for one 25 mm mount during construction.[3]
Built by the Kawasaki Dockyard Co. at their shipyard in Kobe, I-179 was laid down on 21 August 1941 under the name of Submarine No. 157 and renamed I-179 on 1 November 1941. The boat was launched on 16 July 1942 and completed on 18 June 1943.[1] While conducting her sea trials in the Inland Sea on 14 July, she sank with the loss of all 85 officers and crewmen. Her wreck was located four days later at a depth of 265disp=flipNaNdisp=flip at with several hatches and her bow buoyancy tank vent valve open. I-179 was struck from the Navy List on 15 April 1944. Her wreck was salvaged from April 1956 to 1 March 1957 and scrapped at Kure.[4]