* - Modified Flower class

It was said that a Flower would roll on wet grass, and it was probably true. Pretty unsinkable that they were, they had atrocious seakeeping qualities, routinely rolling at 40° in what other vessels sailed like calm seas.
It began in 1939 when a realistic appraisal was made of how few escprts there were. and how many would be neede to fill the defficiency - a lot. To meet this, mass production of ships would need to be undertaken, by simplifying the pre-war designs greatly. Turbines, reduction gearing, modern boilers, fire control systems and the usual refinements were dropped, to allow for production by merchant shipbuilders.
In 1939, Smiths Dockyard & Shipbuilding Co. submitted a sketch design based upon their whaler, the Southern Pride. This design was lengthened by 30 feet over the original, and was internally arranged to suit naval practices.
The only prime mover available in the UK at the time was the venerable triple expansion reciprocating engine, powered by a simple cylindrical boiler. This suited both the inexperienced small dockyards and the RNR / RNVR who would make up the crews of these ships; most were trained and fimiliar with such simple equipment. This was a 185 r.p.m unit, to make for the 16 knots specified by the Admirality. The single, large diamater, slow turning propellor was immersed in 6 feet of water, and they were extremelly manouverable and had a very good propulsive efficieny.
They had a short, tall forecastle terminating forward of thre bridge, and further aft a casing extended boiler and engine rooms, atop which was the bridge, and from which prominent ventilator cowls for thesimple boilers and a large, squat, funnel rose up at a slight rake.
Infront of the bridge, in what looked like a missing part of the forecastle, a large pole mast rose up from the split, and a similar mainmast was positioned aft. This was to provide for the length of aerial needed for a long range wireless set, but after the first six, this was changed to a shorter ranged set. This allowed the mainmast to be omitted, but it was not until the next 100 ships had been completed that there was tiem to move the foremast to behind the bridge. The latter was rather high up, open and protected by a mattress like covering. The asdic operator's hut was mounted in the middle of the brisge, and later, SW type 271 RDF was mounted at the aft end of the bridge.
Original armament comprised of a readily available shielded 4" gun on a bandstand for'ard. The bridge shipped two twin AA machine guns - Hotchkiss or Lewis - and a light AA gun tub agaft the funnel, for preferably a single pom-pom, but a quad 0.5" MG in some vessels. Two DC lobbers amidsips and two rails aft, with a single asdic set lowered through a hatch in the belly.
Originally intended as 'patrol sloops', when Germany overran Europe, they had to foray into the Atlantic, and eventually right across it, so were retermed 'corvettes.' Due to their small size, and insufficient length ( to aloow building on small slips ) they were attrocious seakeepers, but conversely they were very seaworthy, staying out in storms long after destroyers had turned for home.
War experience allowed refinements, but as the ships were kept at sea as much as possible, refits were few and far between, and these changes were made whenever possible, to whatever standards, although generally;

1. The forecastle was extended far aft to provide extra accomodation - this was built in from vessel 51 onwards.
2. Installing SW type 271 RDF at the aft end of the bridge, offset or centred.
3. Replacing the machine guns in the wings with single 20mm Oerlikon AA.
4. Adding an internal degaussing cable.
5. Remodelling the bridge to a more permamnent looking stucture, with RDF and asdic operator's huts.
6. Restepping the foremast aft of the bridge
7. Adding many more depthcharges.
8. Some vessels had a noticable sheer and flare to the bows to improve seakeeping.

Curiously, the Flower class served with ( as well as the RN ) the USN - 15 transferred to make up early war deficiencies here, the RCN - Canadian builds, the Free and Vichy French, France having ordered some prewar and the Kriegsmarine, four having been taken over from the French, as PA.1 - 4.
The "Modified Flower" class embodied all the previous changes from the outset, and also many more;

1. Water tube boilers were used, these were smaller, so extra bunkers and 70 tons of ballast were added. The prominent ventilator cowls also disappeared.
2. Vertical funnels and masts.
3. A Hedgehog ASW mortar was shipped on either side of the 4" gun - mounted higher, so a higher bridge was carried.
4. A homogenous light AA battery of 20mm cannon.

By the time they were in production however, the new frigates were takin over, and production was cut back then cancelled, so only twenty-two were completed.

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