Thetis-class gunboat

The "Thetis"-class gunboats, was a class of five naval ships of the Hellenic Navy, originally developed for the German Navy as "Class 420" and first commissioned in 1961. Similar in size to corvettes, all five vessels were built by Rolandwerft, Bremen. In the German Navy they were designated as "submarine hunters" ().
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.