German prowess in the design, development, and construction of submarines (U-Boats) was more than proven during the fighting of World War 2 (1939-1945) where "Wolfpacks" roamed the many waters of the world - hunting allied merchantmen with near impunity for a time. Some of its late-war additions went on to influence submarine design in both the United States and Soviet Union, helping to lay the ground work for the nuclear-powered types that made up undersea forces of the Cold War period (1947-1991). In the aftermath of the war, Germany was divided amongst the conquerors to become a pro-West "West Germany" and a pro-Soviet "East Germany".
With the Cold War in Europe ready to "get hot" at any moment, both sides dug in their respective heels for the long haul. The period was rife with aircraft, tank, munitions, small arms, and naval developments to rival that of the Second World War.
The first German post-World War 2 submarines became three boats belonging to the "Type 201-class" and these were in commissioned service from 1962 to 1967/68. Then followed the "Type 205-class" which numbered thirteen total boats and brought about more modern qualities - operating from the period of 1962 until their end in 2005. Succeeding this line became the "Type 206-class" which began construction in 1969 (lasting into 1975) and ended with eighteen total boats completed. These operated with the German Navy from 1973 to 2011, a pair eventually being sold off to the Colombian Navy where they continue their service lives today (2019). Sixteen of the lot were retired.
The eighteen Type 206 vessels were designated "U-13" through "U-30".
The Type 206-class was brought about to shore up deficiencies in the earlier Type 205's hull design which was found to be prone to corrosion-based cracking (a terrible quality for any submersible!). This was primarily due to a new, non-magnetic steel hull employed by the boats. As such, the Type 206 was quickly drawn up to succeed the Type 205s in service and these were set to use an all-new, higher-tolerance , steel-constructed hull of non-magnetic design as a result. Work on the succeeding type was conducted in the mid-1960s and a first-order arrived in June of 1969 to originate from two separate West German shipyards.
The eighteen boats were realized in a relatively short amount of time and these went on to have successful service lives in both the West German and resulting unified-German navies. In the latter part of the 1980s, an initiative was begun to modernize the fleet and work began in 1987 to introduce newer, more powerful sonar, newer optics and fire control systems, new torpedoes, upgraded navigation systems, and a revised seven-bladed propeller unit (replacing the original five-bladed propeller). The work, managed by Nordseewerke of Emden, was completed in February of 1992 and the resulting changes were substantial enough to warrant an equally-new designation, this becoming "Type 206A". Just twelve of the eighteen Type 206 boats were modernized in this fashion for, by this time, the Soviet Union was no more - having collapsed in 1990-1991. Remaining boats were retired and scrapped.
The Type 206 displaced 450 tons surfaced and 500 tons submerged. Overall length was 160 feet with a beam of 15 feet and a draught of 14 feet. Power included 2 x MTU marine diesels with a single Siemens-Schuckert-Werke electric motor driving a single propeller shaft astern. The diesels outputted 600 horsepower for surface work while the electric set offered 1,500 horsepower for undersea traveling. Maximum speed in ideal conditions reached 10 knots surfaced and 17 knots submerged. Range was a useful 4,500 nautical miles.
The compact nature of these submarines was due to their intended role of patrolling and attacking in Soviet waters in and around the Baltic in the event of Total War. A compact submersible was easier to handle in confined spaces, as well as shallow waters, though at the expense of internal volume and limited range. The crew numbered just twenty-two men and only eight torpedoes were carried for the 8 x 533mm torpedo tube arrangement. The submarine could also manage mine warfare sorties by carrying up to 24 naval mines externally so there was some tactical flexibility.
Onboard systems included the STN "Atlas" DBQS-21 series sonar, the Thomson-CSF DUUX 2 series passive range-finding sonar, the Safare VELOX sonar intercept system, and the EDO-900 active mine avoidance sonar unit. The Thomson-CSF "Calypso II" filled the surveillance and navigation radar role. Defense was handled by the Thomson-CSF Dr-2000U ESM and Thorn-EMI SARIE suites.
In the post-Cold War world, boats U-23 and U-24 were sold off to the Colombian Navy where they continued their careers as ARC "Intrepido" and ARC "Indomable". U-16 and U-18 followed suit but these were sold to serve as spare parts boats for the in-service pair. The Colombian models are the only in-service Type 206 boats as of January 2019.
Germany, by way of Britain, sold the Type 206 design (as the "Gal-class") to Israel. Three were built and entered service in 1976, ultimately succeeded by the Dolphin-class.