Bay Class Frigate - Design

Design

The Bay class made use of the hull, machinery, lattice mast and superstructure of incomplete Loch class frigates. The armament was altered to suit them to the A/A role, with twin QF 4 in Mark XVI guns fore and aft in mounts HA/LA Mark XIX fitted with remote power control (RPC), controlled by a rangefinder-director Mark V carried on the bridge and fitted with radar Type 285 for range taking. Due to a shortage of supply of 4-inch (10 cm) guns and mountings, many ships had these removed from laid up V and W class destroyer "WAIR" conversions and Hunt class destroyers that were constructive total losses. A pair of Mark V "utility" mounts for twin 40 mm Bofors guns were sited amidships, each with its own predictive Simple Tachymetric Director (STD) for fire control. The A/A armament was completed by a pair of mounts Mark V for twin 20 mm Oerlikon guns, carried in the bridge wings. Later, the Oerlikons were replaced with single mounts Mark VII for Bofors guns, a further pair of which were added amidships on raised platforms. For A/S use, a Hedgehog projector was carried on the fo'c'sle and the quarterdeck carried two racks and four throwers for up to 50 depth charges.

In addition to the Radar Type 285 fire control set, Radar Type 291 air warning was carried at the head of the topmast in addition to Radar Type 276 (later 293) target indication at the masthead. The associated IFF transponders were also carried on the foremast to distinguish between friendly and enemy targets and a high frequency direction finder (HF/DF) was carried on a short pole mainmast aft.

Six Bays were completed to different designs. Dundrum Bay and Gerrans Bay were renamed Alert and Surprise and completed as "despatch vessels", Commander-in-Chief's (C-in-C) yachts for the Mediterranean and Far East Stations. These ships omitted the Mark V Bofors mounts and the aft 4-inch (10 cm) guns and had the superstructure extended to provide additional flag accommodation and stepped a tall mainmast. The four other ships were completed as survey vessels, specifically to deal with the vast numbers of uncharted wrecks and mines around the British Isles from wartime. They were unarmed, except for four 3-pounder saluting guns. They had shorter forward shelter decks and carried survey boats under davits abreast the funnel and minesweeeping gear aft.