Similar in size to
corvettes, all five
Class 420/
Thetis-class vessels were built by
Rolandwerft,
Bremen. Although they were designed, built, and designated as
Subchasers by the German Navy, subchasers became obsolete after the
Second World War due to being unable to keep pace with advancements in submarine technology. Because the ships were designed to chase more modern submarines, they are more commonly referred to as
gunboats. The main armament of
Thetis-class ships consisted of 20 mm and 40 mm guns, Mk 46 Mod5 torpedoes and mines and anti-submarine (A/S) mortars. The ships were also equipped with
sonar. Later the A/S mortars were replaced by a second 40 mm gun and the single torpedo tubes by triple mountings. Upgrades started in 2000 may have included enclosed 40 mm gun mountings and
Rheinmetall 20 mm guns to replace the MGs. The last two ships of the class were decommissioned on 22 April 2010. == Ships in class ==