Type XVII submarine

In the early 1930s Hellmuth Walter had designed a small, high-speed submarine with a streamlined form propelled by high-test peroxide (HTP) and in 1939 he was awarded a contract to build an experimental vessel, the 80 ton , which achieved an underwater speed of during trials in 1940. On 14 November 1941 Admirals Erich Raeder and Werner Fuchs (head of the Kriegsmarines Construction Office) witnessed a demonstration of the V-80; Raeder was impressed, but Fuchs was slow to approve further tests. Following the success of the ''V-80's'' trials, Walter contacted Karl Dönitz in January 1942, who enthusiastically embraced the idea and requested that these submarines be developed as quickly as possible. An initial order was placed in summer 1942 for four development submarines. ==Construction==

Of these, and , designated Wa 201, were built by Blohm + Voss, achieved submerged. The other pair, and , designated Wk 202, were constructed by Friedrich Krupp Germaniawerft, Kiel. The U-793 achieved a submerged speed of in March 1944 with Admiral Dönitz aboard. In June 1944 U-792 achieved over a measured mile. The submarines were found to be very hard to handle at high speed, and were plagued by numerous mechanical problems, low efficiency, and the fact that a significant amount of power was lost due to increased back pressure on the exhaust at depth. Also, the length to beam ratio was too low, resulting in an unnecessarily high drag. Construction of operational Type XVII submarines – the Type XVIIB – was begun at the Blohm + Voss yard in Hamburg. The Type XVIIB, unlike the Wa 201 and Wk 202, had only a single turbine. The initial order was for 12 submarines, U-1405 through U-1416. However, Blohm + Voss were already struggling to cope with orders for Type XXI submarines and the Kriegsmarine reduced the order to six. ==Projected types==

Twelve Type XVIIG of slightly improved design, U-1081 through U-1092, were at the same time ordered from Germaniawerft. A projected Type XVIIK would have abandoned the Walter system for closed-cycle Diesel engines using pure oxygen from onboard tanks. The only boat, U-798, was still unfinished at the Krupp Germaniawerft at the end of the war. ==Completed boats==

Three Type XVIIB boats were completed by Blohm + Voss of Hamburg between 1943 and 1945: , and . U-1405 was completed in December 1944, U-1406 in February 1945, and U-1407 in March 1945. A further three boats (U-1408 to U-1410) were under construction, but were not complete when the war ended. Another six Type XVIIB's (U-1411 to U-1416) were cancelled during the war in favour of the Type XXI submarine. ==Post war==

All three completed Type XVIIB boats were scuttled by their crews at the end of World War II, U-1405 at Flensburg, and U-1406 and U-1407 at Cuxhaven, all in the British Zone of Occupation. At the Potsdam Conference in July 1945 U-1406 was allocated to the United States and U-1407 to Britain, and both were soon salvaged. The uncompleted U-1408 and U-1410 were discovered by British forces at the Blohm + Voss yard in Hamburg. The Royal Navy repaired U-1407 and recommissioned her on 25 September 1945 as . She served as the model for two further HTP boats, the s, and . ==List of boats==

Wa 201 — Blohm + Voss, Hamburg • — only used as a trials vessel; scuttled on 4 May 1945 • — only used as a trials vessel; scuttled on 4 May 1945 Wk 202 — Germaniawerft, Kiel • — only used as a trials vessel; scuttled on 5 May 1945 • — only used as a trials vessel; scuttled on 3 May 1945 Type XVIIB — Blohm + Voss, Hamburg • — scuttled on 5 May 1945 • — scuttled on 7 May 1945, raised, and transported to the U.S.; broken up some time after 18 May 1948 • U-1407 — scuttled on 7 May 1945, raised, repaired and served as until September 1949 • U-1408 – 1410 — incomplete when the war ended • U-1411 – 1416 — contract cancelled before construction began ==References==