The Type 209 is a class of diesel-electric attack submarine developed exclusively for export by Howaldtswerke-Deutsche Werft of Germany. The original variant (Type 209/1100) was designed in the late 1960s. Despite not being operated by the German Navy, five variants of the class (209/1100, 209/1200, 209/1300, 209/1400 and 209/1500) have been successfully exported to 13 countries, with 61 submarines being built and commissioned between 1971 and 2008.The submarine was designed by Ingenieurkontor Lübeck (IKL) headed by Ulrich Gabler and is largely based on previous German submarine designs (in particular the Type 206) with increased equipment. The design is single hulled and allows the commanding officer to see the entire submarine from the bow to stern while standing at the periscope.[4] Four 120-cell batteries are located forward and aft of the command center in the lower deck and make up about 25% of the boat's displacement.[3] Two main ballast tanks with forward and aft trim tanks allow the boat to dive. They are powered by four MTU diesels and four AEG generators.[5] The AEG electric motor is attached directly to a five- or seven-bladed propeller.In the early 1970s, many navies began to need replacements for WWII-era submarines, aging United States GUPPY conversions, and British units transferred postwar.[3] During this time, few western submarine designs were available for export as most were large, expensive, sophisticated and difficult to operate, and designed for the Cold War. Several designs originally built for specific nations were available including the French Daphne Class, British Oberon Class, and the Soviet Foxtrot Class submarines.[4] The design, designated by the German Ministry of Defense as the “Type 209” provided a solution providing the combination of size, performance, relative ease of operation for small or inexperienced navies, reasonable price and economy of operation