Polygons 25564 Vertices 26207 The Type IX U-boat was designed by Germany in 1935 and 1936 as a large ocean-going submarine for sustained operations far from the home support facilities. Type IX boats were briefly used for patrols off the eastern United States, in an attempt to disrupt the stream of troops and supplies bound for Europe. The extended range came at the cost of longer dive times and decreased maneuverability, which is why the smaller Type VII was produced in greater numbers and used for the bulk of operations. It was derived from the Type IA, and appeared in various sub-types. Type IXs had six torpedo tubes, four at the bow and two at the stern. They carried six reloads internally and had five external torpedo containers three at the stern and two at the bow which stored ten additional torpedoes. The total of 22 torpedoes allowed U-boat commanders to follow a convoy and strike night after night. As mine-layers they could carry 44 TMA or 66 TMB mines, but many of the IXC boats were not fitted for mine operations. Secondary armament was provided by one large Utof 105/45 gun with about 110 rounds. Anti-aircraft armament differed throughout the war. They had two periscopes in the tower. Types IXA and IXB had an additional periscope in the control room, which was removed in Type IXC and afterward.