River Class frigate

Designed as ocean-going escorts with a range of 12970 km (8,060 miles), the ‘Rivers’ were at first fitted with almost totally superfluous minesweeping gear. Once this was eliminated from the design, oil storage rose from 440 tons to 646 tons, with a consequent improvement in endurance.

As in the case of the United States, the British also pursued the construction of escort destroyers for ASW and AA defense roles. These duties were deemed extremely important by British naval officials in the event of a war with Germany and had been foreseen by October 1938. Great Britain was the pioneer of the escort destroyer type through the production between 1939 and 1940 of the 23 Hunt-class escort destroyers. A Hunt-class ship measured 280 feet by 29 feet by 12 feet, 6 inches and displaced 1,000 tons. The vessel was armed with four 4-inch guns in single mounts and four 2- pounder pom-pom weapons. Most lacked any torpedo battery. This was the result of the fact that the ship was designed specifically for the protection of convoys against submarines. The Hunt-class units carried an impressive ASW armament that totaled between 50 and 110 depth charges. The turbine engines of one of these ships produced 28 knots. By the end of the war, the British launched three more batches of escort destroyers that were improved Hunt-class ships. In total, the Royal Navy operated 86 vessels of the Hunt-class design.

Supplementing these vessels were the frigates of the Royal Navy. Great Britain pioneered the design of frigates with the River class, first launched in 1942. A River-class vessel measured 301 feet, 4 inches by 36 feet, 8 inches by 11 feet, 10 inches and displaced between 1,310 tons and 1,460 tons. Its armament consisted of only two 4-inch guns, but it possessed a large ASW battery. This consisted of a Hedgehog and 126 depth charges mounted primarily in racks. The large amount of antisubmarine ordnance is evidence of the fact that the frigate of the Royal Navy, like that of the United States, was intended solely for use against submarines while escorting merchantmen. Great Britain built several classes following that of the original River type. By the end of the war, the Royal Navy operated 349 escort destroyers and frigates.

With the limitations of the ‘Flowers’ readily apparent, the Admiralty rapidly produced a design for a larger ‘twin-screw corvette’ which became known as the ‘River’ class. (The term ‘frigate’ was not officially reintroduced until 1942). Overall they were about 28.30m(93 ft) longer than the later ‘Flowers’ and this made a very great difference in seakeeping, bunker capacity, installed power and armament, Between 1942 and 1944 some 57 were launched in the UK, 70 in Canada and 11 in Australia.

The hull had the raised forecastle extended well aft, with a low quarterdeck for the depth-charge gear and the minesweeping equipment with which too many useful escorts were cluttered at that time. They were the first ships to be fitted as standard with the Hedgehog anti-submarine spigot mortar which, with new sonar gear, made for a more rapid and accurate attack. The Hedgehog was originally sited well forward and was thus extremely exposed, but later units had the weapon split into two 12-bomb throwers which were sited one deck higher, winged out abaft the forward 101.6-mm (4-in) gun. Longer endurance demanded a larger depth charge capacity, and up to 200 could be carried, compared with a maximum of 70 on the ‘Flowers’.

Though not developed from a mercantile hull form the ‘Rivers’ were built to mercantile standards, which speeded construction. They featured a flat transom, which not only obviated much of the complex curvature of traditionally-shaped sterns but also actually improved the hull hydrodynamics. It is noteworthy that over half the ‘Rivers’ were Canadian-built (with more ships coming from Australia) and it is probably all too easily overlooked how magnificent a contribution the Canadian yards and the Royal Canadian Navy made to victory in the Atlantic. Most Canadian-built units had a twin 101.6-mm mounting forward and a single 12-pdr aft. They also had their full outfit of 14 20-mm weapons, which British-built ships rarely achieved. The machinery was simply that of the ‘Flowers’ doubled, though drawing steam from more efficient water-tube boilers. Four ships only were built with steam turbines, which were not generally adopted as a result of shortages of components. The ‘Rivers’ were highly successful, but most of the survivors (seven were sunk in the war) had been scrapped by the mid-1950s. Further ‘Rivers’, to a slightly modified design, were built by the Americans as the ‘PF’ type; of these 21 served in the Royal Navy as the ‘Colony’ class.

River Class Frigates

Adur* (K269), Rother (K224), Spey (K246), Swale (K217), Tay (K232), Exe (K92), Waveney (K248), Test (K239), Wear (K230), Jed (K235), Lagan (K259), Kale (K241), Ness (K219), Itchen (K227), Moyola (K260), Teviot (K222), Nith (K215), Cuckmere (K299), Trent (K243), Tweed (K250), Mourne (K261), Bann (K256), Dart (K21), Derg (K257), Ribble (K525), Ettrick (K254), Strule (originally Glenarm) (K258), Ballinderry (K255), Chelmer (K221), Deveron (K265), Nene (K270), Plym (K271), Towey (K294), Helford (K252), Fal (K266), Tavy (K272), Usk (K295) (ii), Aire (K262), Tees (K293), Helmsdale (K253), Windrush (K370), Meon (K269), Braid (K263), Cam (K264), Wye (K371), Dovey (K523), Torridge (K292), Odzani (K356), Avon (K97), Taff (K637), Nadder (K392), Lochy (K365), Monnow (K441), Teme (K458), Awe (K526), Halladale (K471), Annan (K404).

*Transferred immediately to the United States Navy and did not enter service.

River class frigates were first mooted in late 1940 when it was realised that something larger would be better suited for the Atlantic convoys – and a higher speed of 22 knots was also considered desirable. The River class were built to merchant ship practice, and like the Flower class used triple expansion steam engines, although with two rather than the single engine of the Flowers. Minesweeping gear was usually fitted.

General characteristics RN group I
Displacement: 1,370 long tons (1,390 t; 1,530 short tons) 1,830 long tons (1,860 t; 2,050 short tons) (deep load)
Length: 283 ft (86.3 m) p/p 301.25 ft (91.8 m)o/a
Beam: 36 ft 6 in (11.1 m)
Draught: 9 ft (2.7 m); 13 ft (4.0 m) (deep load)
Propulsion: 2 × Admiralty 3-drum boilers, 2 shafts, reciprocating vertical triple expansion, 5,500 ihp (4,100 kW) (except Cam, Chelmer, Ettrick, Halladale, Helmsdale, and Tweed; Parsons single reduction steam turbines, 6,500 shp (4,800 kW)
Speed: 20 knots (37 km/h; 23 mph) 20.5 knots (38.0 km/h; 23.6 mph) (turbine ships)
Range: 7,200 nautical miles (13,300 km; 8,300 mi) at 12 knots (22 km/h; 14 mph) with;440 long tons (450 t; 490 short tons) oil fuel
Complement: 107
Armament: 2 × QF 4 in (102 mm) /40 Mk.XIX guns, single mounts CP Mk.XXIII Up to 10 × QF 20 mm Oerlikon A/A on twin mounts Mk.V and single mounts Mk.III 1 × Hedgehog 24 spigot A/S projector 8 x depth charge throwers, 2 x rails, Up to 150 depth charges
General characteristics (RN group II)
Range: 646 long tons (656 t; 724 short tons) oil fuel; 7,500 nautical miles (13,890 km) at 15 knots (27.8 km/h)
Notes: Other data per RN group I
General characteristics (RCN group)
Displacement: 1,445 long tons (1,468 t; 1,618 short tons) 2,110 long tons (2,140 t; 2,360 short tons) (deep load)
Range: 646 long tons (656 t; 724 short tons) oil fuel; 7,500 nautical miles (13,890 km) at 15 knots (27.8 km/h)
Complement: 157
Armament: 2 × QF 4-inch (101.6 mm) XVI guns on twin mount HA/LA Mk.XIX 1 × QF 12-pdr 12 cwt (3-inch (76.20 mm)) Mk. V gun on mounting HA/LA Mk.IX (not all ships) 8 × 20 mm QF Oerlikon A/A on twin mounts Mk.V 1 × Hedgehog 24 spigot A/S projector Up to 150 depth charges
Notes: Other data per RN group I
General characteristics (RAN group I)
Displacement: 1,420 long tons (1,440 t; 1,590 short tons) 2,020 long tons (2,050 t; 2,260 short tons) (deep load)
Range: 500 long tons (510 t; 560 short tons) oil fuel; 5,180 nautical miles (9,593 km) at 12 knots (22.2 km/h)
Complement: 140
Armament: 2 × QF 4-inch (101.6 mm) Mk.XVI guns, single mounts HA/LA Mk.XX 8 × QF 20 mm Oerlikon, single mounts Mk.III, later; 3 × QF 40 mm Bofors, single mounts Mk.VII 4 × QF 20 mm Oerlikon, twin mounts Mk.V 1 × Hedgehog 24 spigot A/S projector Up to 50 depth charges
Notes: Other data per RN group I
General characteristics (RAN group II)
Displacement: 1,545 long tons (1,570 t; 1,730 short tons) 2,185 long tons (2,220 t; 2,447 short tons)
Complement: 177
Armament: 4 × QF 4-inch (101.6 mm) Mk.XVI guns, twin mounts HA/LA Mk.XIX 3 × QF 40 mm Bofors, single mounts Mk.VII 4 × QF 20 mm Oerlikon, twin mounts Mk.V 1 × Hedgehog 24 spigot A/S projector Up to 50 depth charges
Notes: Other data per RAN group I