The last Flowers were launched at the beginning of 1942 and, insofar as the knowledge of their limits for operations in the North Atlantic had already led to the realization of the real frigate, the corvette seemed to have reached the end of its life. development. There were, however, a number of small shipyards which, committed to the Flower construction program, did not have the material means to undertake the manufacture of the frigates. To keep them busy, a larger corvette, between the lengths of the Flowers and the Rivers, was developed by Smith's Dock. Named after British castles, the units of the new Castle class benefited from the lessons learned from the experience of their elders while managing to resemble them in an astonishing way. The hulls had the same pleasing lines, although they were largely welded to facilitate mass production. The fore and aft sections had a constant bearing angle and the wide, flat transom simplified construction and gave plenty of room aft. Forty-four ships were launched in 1943-1944, and thirty-eight others were cancelled.
The Castles had the vast bridge of the frigates and a large lattice mast designed to support the considerable mass of the first radars, whose enlargement of the hull allowed the installation. They embarked the Squid anti-submarine mortar, a weapon too heavy to be retrofitted on the Flowers or the Rivers, and which was placed on the front of the bridge, behind a 101.6 mm gun of a new kind. The Squid had the advantage of being able to launch a group of three large bombs on a submerged target which, located up to 500 m, was still in the sonar wave beam. These buildings having retained the reciprocating steam engine of the Isles and Flower classes, their performance was not worth that of the frigates.
Features
Castle Class
Displacement :1,060 standard t.
Dimensions:
length , 76.80 m;
width , 11.20 m;
draft , 3.05 m.
Engine apparatus :4-cylinder triple expansion steam engine developing 2,950 hp and driving 1 shaft.
Speed speed:16.5 knots.
Range :6,910 km at 15 knots.
Armament :1 x 101.6 mm mixed gun, 2 x 20 mm twin and 6 single AA guns, 1 Squid and ASM grenades.
Crew :120 officers and sailors.