Gotland class

   Resulting from a research and preliminary design contract placed with the Kockums yard of Malmo in October 1986 for a conventionally powered submarine to replace the obsolescent boats of the Sjoormen class, the design of the boats of the A19 or Gotland class was derived from that of the A17 or Vastergotland class. The three boats of the class, namely the Gotland, Upland and Halland, were ordered from Kockums in March 1991, but another two projected units were not in the event procured. In September of the following year, before the first boat had been laid down, the programme was temporarily suspended to allow a reworking of the design to incorporate, for the first time before the start of fabrication rather than as a retrofit, an AIPS (Air-Independent Propulsion System), using liquid oxygen and diesel fuel in a helium environment, for much enhanced submerged operating capability. The design of the hull was lengthened by 7.5 m (24 ft 7 in) to allow the incorporation of two such systems with volume left for the later addition of another two systems should this prove desirable. As it is, the boats can apparently cruise at a submerged speed of 5 kts for several weeks without recourse to snorting.

   The boats were laid down in 1992-1994, launched in 1995-96, and commissioned in 1996-97, the lengthening of the hull having resulted in a 200-ton increase in displacement. Another advanced feature of the design was the installation of a periscope with optronic sensors, and this unit is the only mast that penetrates through the pressure hull. The boats underwater signature is being further reduced by the application of anechoic coatings.

   The torpedo tubes are all located in the bow, and comprise four 533-mm (21-in) tubes over two 400-mm (15.75-in) tubes. The larger units fire anti-ship torpedoes of the swim-out type in the form of the wire-guided Type 613 passive or (since 2000) Type 62 active/passive weapons: the former carries a 240-kg (529-lb)_HE warhead to 20 km (12.4 miles) at 45 kts, while the latter carries a 250-kg (551-lb) HE warhead to 50 km (31,1 miles) at a speed of mines can be carried in place of the heavy torpedoes, these swimming out to a predetermined position before laying themselves on the bottom. Another 48 mines can be carried by an external girdle. The smaller torpedo tubes can be tandem loaded with wire-guided Tp 432/451 active/passive ASW torpedoes, each able to carry a 45-kg (99-lb) HE warhead out to 20 km (12.4 miles) at 25 kts.