In December 2005, Brazil commissioned the submarine Tikuná (S 34) into service. The submarine, a German Type 209 variant, is the fifth and final boat of this class to enter service with the Brazilian fleet. Construction of the submarine took a decade to complete because of numerous delays and a two-year work stoppage. The delays, however, contributed to numerous improvements, including a lengthened hull that allows for a more powerful propulsion system and improved endurance, automatic depth control, reduced radiated noise, a freshwater distilling system, a new weapons control system, improved air conditioning systems as well as fittings to accept a submarine rescue submersible and the ability to put two people at a time into the rescue lock-out chamber. The lead submarine of the class, Tupi (S 30), shown to the right, was built in Kiel, Germany at Howaldtswerke Deutsche Werft (HDW) Shipyard. The remaining units of the class, Tamoio (S 31), Timbira (S 32), Tapajó (S 33), and Tikuná were all built in Brazil by Arsenal do Marinha de Rio de Janeiro.