The
Whitby-class was designed as a class of specialist anti-submarine warships, intended to counter fast modern diesel-electric submarines. As such, the design was required to reach a speed of at least , maintaining high speed in rough weather conditions and have a range of at . To meet these requirements, the Type 12s had a new hull form and, unlike the contemporary
Type 41 anti-aircraft and
Type 61 air direction frigates, were powered by
steam turbines.
Whitby was
long overall and
at the waterline, with a
beam of and a
draught of forward and at the propellers. The ships were powered by the new Y-100 machinery in which the ship's boilers and steam turbines were designed as a closely integrated set of machinery to increase efficiency. Two
Babcock & Wilcox water-tube boilers fed steam at and to two sets of geared
steam turbines which drove two propeller shafts, fitted with large ( diameter) slow-turning propellers. The machinery was rated at , giving a speed of . Crew was about 189 when operated as a leader and 152 as an ordinary ship. A twin
4.5-inch (113 mm) Mark 6 gun mount was fitted forward, with 350 rounds of ammunition carried, with close-in armament of a stabilised STAAG (Stabilised Tachymetric Anti-Aircraft Gun) twin
Bofors 40 mm L/60 gun mount aft. The design anti-submarine armament consisted of twelve 21-inch torpedo-tubes (eight fixed and two twin rotating mounts) for
Mark 20E Bidder homing anti-submarine torpedoes, backed up by two
Limbo anti-submarine mortars fitted aft. The Bidder homing torpedoes proved unsuccessful however, being too slow to catch modern submarines, and the torpedo tubes were soon removed. The ship was fitted with a
Type 293Q surface/air search radar on the
foremast, with a
Type 277 height-finding radar on a short mast forward of the foremast. A Mark 6M fire control system (including a Type 275 radar) for the 4.5 inch guns was mounted above the ship's bridge, while a Type 974 navigation radar was also fitted. ==Service==