Hunt-class destroyer explained

The Hunt class was a class of escort destroyer of the Royal Navy. The first vessels were ordered early in 1939, and the class saw extensive service in the Second World War, particularly on the British east coast and Mediterranean convoys. They were named after British fox hunts. The modern Hunt-class GRP hulled mine countermeasure vessels maintain the Hunt names lineage in the Royal Navy.

History

The Royal Navy had identified the need for two types of destroyer: larger vessels with heavy gun and torpedo armaments for fleet work and another type for escort duties. Although old fleet destroyers could be allocated to escort work, they were unsuitable for the task and new construction replaced them. Fleet destroyers were designed for speed and their machinery was inefficient at convoy speeds, reducing their range. Their shape made them poor sea boats at low speed, also exacerbated by additional equipment on the superstructure. Modifications were needed to ease these problems.

The escort vessels forsook the heavy armament and some of the speed of the fleet type to reduce unit cost and better suit mass production and the conditions. This new "fast escort vessel" was later classified as an "escort destroyer".

Eighty-six Hunts were completed, of which 72 were commissioned into the Royal Navy and the remaining 14 were transferred to allied navies; Bolebrooke, Border, Catterick, Hatherleigh, Modbury, Bramham and Hursley to the Greek Royal Hellenic Navy, Bedale, Oakley (i) and Silverton to the Free Polish Navy, Glaisdale, Eskdale and Badsworth to the Royal Norwegian Navy and Haldon to the Free French Navy.

Design

The Hunts were modelled on the 1938 escort sloop, a 2620NaN0 ship of 1,190 tons with 3300shp on geared turbines for and an armament of three twin Mark XIX mounts for the QF 40NaN0 gun Mark XVI. The guns were controlled by a Fuze Keeping Clock AA fire control computer when engaging aircraft. The Hunt class was to ship the same armament, plus a quadruple QF 2-pounder mount Mark VII on a hull of the same length but with 8feet less beam and installed power raised to 19000shp to give 27kn. The first twenty were ordered in March and April 1939. They were constructed to Admiralty standards, as were contemporary destroyers, unlike the frigates, which conformed much more to mercantile practice.

Clearly, the Hunts posed a major design challenge. They would be too short and narrow and of insufficient range for open ocean work, being restricted to the North Sea and Mediterranean Sea. This sacrifice was accepted to give any chance of meeting the requirements. The demanding specifications in an overworked Admiralty design department resulted in a major design miscalculation. When the detailed calculations were done the centre of gravity was higher than expected and the beam was increased. As the first ships were being completed it was found that the design was as much as 70 tons overweight, top-heavy, leaving them dangerously deficient in stability. The first twenty ships were so far advanced in construction that it was necessary to remove the 'X' 4-inch gun mount and add 50 tons of permanent ballast. These ships became the Type I group and had the multiple 2-pounder guns relocated from behind the funnel to the more advantageous 'X' position.

The design deficiency of the Type I was rectified by splitting the hulls lengthwise and adding a 2½ foot section, increasing the beam to 31 ft 6 in and the margin of stability sufficiently for the designed armament to be shipped. These ships became the Type II group, and also had a revised design of bridge with the compass platform extending forwards to the wheelhouse face. Under the 1939 Emergency War Programme, 36 more Hunts had been ordered; three of these were completed to the original (Type I) design. Depth charge stowage could also be increased from 40 in the Type I to 110.

For the 1940 building programme, torpedoes were deemed necessary. The next 27 ships were completed to a revised design, the Type III group, and were intended for Mediterranean work. They sacrificed 'Y' gun for a pair of 21-inch torpedo tubes amidships, the searchlight being displaced to the aft shelter deck as a result. The Type III Hunts could be easily identified as they had a straight funnel with a sloping top and the foremast had no rake. Fourteen of them had their stabiliser fins removed (or not fitted in the first place) and the space used for extra fuel oil.

The last two Hunts came from an independent lineage and were built to a private design that had been prepared pre-war by John I. Thornycroft & Company. Submitted to the Admiralty and rejected in 1938, a modified design had been accepted in 1940. They were known as the Type IV. They had a novel hull design, with a U-shaped forward section with a distinctive double knuckle and a full centre section with a square turn at the bilge. This form was intended to increase low-speed efficiency and reduce rolling without the need for ballast or stabilisers to improve the ships as gun platforms; testing showed an 8% increase in steaming efficiency at 20kn for a 2% loss full ahead. Other features included a long fo'c'sle stretching for most of the length of the ship, which increased internal accommodation space (the lack of which was a perennial problem in wartime ships with enlarged crews) and allowed the crew to fight the ship almost completely under cover. 'X' gun was now at the fo'c'sle deck level rather than on a raised shelter deck. The design was large enough to carry a triple set of torpedoes but as they too were at fo'c'sle deck level the training apparatus had to be remotely mounted a deck below.

Armament was completed by a pair of 20 mm Oerlikon guns on the bridge wings and a pair of power operated twin 0.5-inch Vickers machine guns amidships. This was quickly discovered to be ineffective and was replaced by the Mark V twin mounting for the Oerlikon guns. The level of protection afforded to the crews in these two ships was found to be beneficial in wartime, where crews were often closed up at action stations for extended periods of time in appalling weather conditions, and the design – although it was something of a dead end – influenced post-war escort designs. All Hunt class except three Type II and the Type IV Brissenden had fin stabilisers forward to reduce rolling to make for a steadier gun platform. These were subsequently removed from the majority of the Type III ships to allow for an increase in bunkerage of 63 tons.

Modifications

The Hunt class was a very satisfactory design, but had limited surplus displacement to allow any major modifications. All ships had a pair of single Oerlikon guns added in the bridge wings as they became available, and Type 285 radar added to the Rangefinder-Director Mark I carried on the bridge for the main armament. The air warning Type 286 radar was added at the masthead, later replaced by Type 291, and Cotswold, Silverton, Bleasdale and Wensleydale had their searchlight replaced by Type 272 radar, a centimetric target indication set.

Those vessels employed on East Coast convoy work, all the Type Is, the Type IIs Avon Vale, Blencathra and Liddesdale and the Type IIIs Bleasdale and Glaisdale were fitted with a single QF 2-pounder "bow chaser" gun for anti-E-boat work. Most Type IIIs later had their single Oerlikon guns replaced with twin powered mountings Mark V, and some had two single 40 mm Bofors guns added, one each forward of the wheelhouse and on the quarterdeck.

Type I

The first ten of the following were ordered on 21 March 1939, and the other ten on 11 April 1939. Three more were ordered on 4 September 1939 (see below) were intended to be of Type II, but were actually completed to the Type I design.

Type II

Eighteen were ordered on 4 September 1939 and two more (Lauderdale and Ledbury) on the following day. Three of these were completed with the same armament as the Type I – Blencathra, Brocklesby and Liddesdale. A final batch of sixteen were ordered on 20 December 1939.

Type III

Type IV

These very distinct vessels were built to a radically different private design by Thornycroft at Southampton, ordered on 28 July 1940.

Bibliography

External links

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