Before conversion began, all superstructure, weaponry, masts and equipments were removed and the machinery was overhauled. The forecastle was extended backwards to leave only a small quarterdeck, providing much improved accommodation, the lack and poor quality of which had been a source of constant problem for large wartime crews. A new single-level superstructure incorporating the fully enclosed bridge (a novelty in a British escort ship), operations room and a sonar room was added spanning the full width of the hull in front of the funnel. The new superstructure layout allowed the crew to fight the ship without having to expose themselves to the elements, and was increasingly important in the age of nuclear weapons. New lattice masts were provided to carry the range of radars, HF/DF and communications equipment that were now required for a naval escort. Troubridge, Ulster and Zest were fitted with a new design of bridge that would be adopted in all subsequent British frigates up to the Leander class. This bridge had angled sides and raked windows, to allow good all-round vision and cut down on internal reflections at night.
A completely new suite of armaments and electronics was added, befitting their role as fast anti-submarine frigates. The armament was centred around a pair of Mark 10 Limbo A/S mortars. These three-barrelled weapons were based on the wartime Squid, and were mounted on the quarterdeck aft, where they were best protected from the weather. They had a 360° field of fire and were automatic in operation. It had been intended to carry a new anti-submarine weapon, the Mark 20E torpedo, in a pair of trainable tubes on each beam, but this weapon was a failure and the tubes, where fitted, never received weapons and were later removed. Rapid, Roebuck and all V and W class ships carried Squids in lieu of Limbo due to insufficient funds existing to fit all ships with Limbo. For self defence, a twin 4 inch gun on a Mounting Mark XIX was carried aft, controlled by the MRS-1 Close Range Blind-Fire director (CRBF). Behind the bridge was fitted a twin 40 mm Bofors gun on a "utility" Mounting Mark V.
Many vessels were used during their peacetime service as seagoing training ships, for which purposes the 40 mm gun was removed and a large open bridge was added above the rounded face of the existing bridge. Undaunted was built with a flight deck aft, and was used for trials of the Fairey Ultra-light and Saunders Roe P531 helicopters. Undaunted became the first frigate to carry and operate a helicopter. Grenville had a flight deck fitted in 1959, but this was later removed.
| General characteristics | |
|---|---|
| Displacement: | 2,300 long tons (2,337 t) standard 2,700 long tons (2,743 t) full load |
| Length: | 358 ft (109 m) o/a |
| Beam: | 37 ft 9 in (11.51 m) |
| Draught: | 14 ft 6 in (4.42 m) |
| Propulsion: | 2 × Admiralty 3-drum boilers Steam turbines on 2 shafts 40,000 shp (30 MW) |
| Speed: | 31 knots (57 km/h; 36 mph) (full load) |
| Complement: | 174 |
| Sensors and processing systems: | Radar
Sonar:
|
| Armament: | • 1 × twin 4 in (100 mm) Mark 19 gun |
| Aviation facilities: | Flight deck on Grenville and Undaunted |
