Cath Mudford Website

HMS Quilliam J Class Fleet Destroyer

Introduction

Destroyers are small warships (defined in the London Treaty of 1930 as being no more than 1,850 tons), and armed with light weapons (guns of calibre no more than 5.1 inches (130 mm)). In the British Royal Navy during World War II a ship must also be fitted with torpedo tubes to be classed as a destroyer. They are usually equipped for anti-submarine work, although some may alternatively be equipped for minelaying operations.

Before World War II, new British destroyers were generally designated as fleet destroyers, for work in support of the main fleet, which includes cruisers and capital ships. Experience during the war lead to older destroyers often being refitted and re-designated as escort destroyers (principally because older destroyers lacked the speed of modern warships) and used for less glamorous tasks such as convoy escort. The need for new specialist escort destroyers was recognised, however, and these were also built during the war. The J class ships are fleet destroyers, equipped for anti-submarine work.

Eight ships formed the J class (HMS Jervis as the flotilla leader, with the others being HMS Jersey, HMS Jaguar, HMS Juno, HMS Jupiter, HMS Janus, HMS Jackal, and HMS Javelin). They mainly served in the Mediterranean, and were fitted with improved anti-aircraft armament compared to all previous British destroyers. Nevertheless, (as with all small ships) they were extremely vulnerable to air attack and later fleet destroyers tended to have anti-aircraft armament that was better still. Only two ships survived the war, with five being sunk before the end of 1942.

Despite the heavy losses of J class it was generally accepted that the design was sound, and formed the basis for the 'emergency' designs that followed. A total of 124 ships entered service as variations on the J class design, although 28 of these were completed after the end of hostilities.

Development

The naval treaties between the wars had a significant effect on the design of all warships. Weight limitations forced all naval powers to focus on weight saving designs, bringing significant advances in several areas, such as advanced propulsion systems and dual purpose weaponry (to be used in both surface and air actions). The previous destroyer class - the Tribal class - were very much larger than all other existing British destroyers, with a correspondingly greater cost to build. The J class was intended to be a compromise, smaller and cheaper than the Tribal class and yet with comparable speed and armament.

The J class were fitted with a total of six main guns and 10 torpedo tubes, compared to the Tribal class with eight main guns and four torpedo tubes. This increase in torpedo tubes represented a significant improvement in the capabilities of the ship over the Tribal class, giving them a bigger punch against capital ships. The reduction in main guns from eight to six was in practice not significant, and as most British destroyers were only armed with four guns the J class were considered to be heavily armed.

There had long been a desire to produce dual purpose guns for destroyers which could be used both against aircraft and against surface targets. The Admiralty was having considerable trouble developing a high-angle gun mounting, and eventually it was decided to retain the low angle mount, which was limited to a maximum of 40 degrees elevation. As with the Tribal class, each mount was fitted with twin 4.7 inch (119 mm) guns. After considerable debate within the Admiralty the aft gun was designed to train in a forward position, which resulted in a blind spot over the stern of about 20 degrees whilst providing for easier engagement of targets ahead. This decision represented the traditional favour of offensive action over defensive measures. These guns were capable of firing 10 rounds per minute each, with the rounds weighing 50 pounds (22.8 kg).

For air defence a four barrelled pom-pom was fitted. This at last gave British destroyers some defence against dive-bombers, as they fired 115 rounds per minute per barrel, and were effective out to 1100 metres (1203 yards). Finally, eight 0.5 inch (13 mm) machineguns were installed in two mounts of four guns each, although these were found to be prone to jamming.

For the anti-submarine role the ships were fitted with asdic and depth charges. Asdic was a standard feature of British destroyers at this time. It was effective out to about 2500 yards (2286 metres), although high speed and bad weather both adversely affected its operation. Generally asdic was ineffective if the ship was travelling above about 18 knots, and was unable to detect anything within about 200 yards (183 metres) of the ship. Two racks of depth charges were provided at the stern of the ships, as well as two depth charge throwers on either side. Depth charges had to explode within about 20 feet (6.1 metres) of a submarine to breach its hull, and in the initial stages of the war the British depth charges' maximum setting was over 100 feet (30 metres) shallower than the maximum depth that a U-boat could dive to.

To protect the fleet from mines provision for a two speed destroyer sweep (TSDS) was fitted to all but HMS Jervis, who as the flotilla leader had increased accommodation for staff which reduced the space available at the stern of the vessel.

The J class was the first to have only a single funnel, with improvements in boiler design allowing the ships to be fitted with two more powerful boilers rather than the three fitted to the previous Tribal class destroyers, with the net power output being similar.

Longitudinal framing was chosen for the J class which, when combined with electric arc welding, allowed the ship to be built more easily. Transverse frames were still required around the machinery spaces however, to provide the required structural support.

A destroyer's primary assets were speed and manoeuvrability. As with all destroyers, no attempt was made to provide armour. This was because the amount required to protect the ship from enemy weapons would result in a prohibitive increase in weight, greatly reducing speed whilst increasing the size of the ship (effectively turning the destroyer in to a very poorly armed cruiser).

There was some discontent when it was found that the J class were only slightly smaller than the Tribal class (356.5 feet compared to 377 feet for the Tribals), had fewer main guns (six compared to eight), and yet cost more to build (£390,000 each compared to £340,000). Their performance silenced the critics, and the basic hull form was used in many future variants.

It was originally intended that destroyers operate in groups of nine, with eight ships under the control of one Captain (Destroyers), normally known as Captain (D), in a ninth (larger) vessel. This arrangement was found to be difficult to control in exercises just before the war, and tactical units of four destroyers were seen to be more flexible. It was thus decided to build eight J class ships, with the ninth (HMS Jubilant) being cancelled before building began. This also reduced the cost and simplified the creation of destroyer fleets as considerable effort was needed to create the single special larger vessel for Captain (D) and his staff. Modifications to the ships were made during the war, following the general trend of improving anti aircraft armament and providing radar capability

There is a tradition in shipbuilding of finding a design that works, then modifying it for other newer ships so that the best of the old can be combined with new knowledge. Evolution rather than revolution is the watchword. The reasons for this are complex, but given the unpredictable nature of the sea, the time and cost of construction, the difficulty of predicting performance for a new design (still a problem today), the need for more destroyers quickly, the inability to build a prototype for testing, the difficulty of future modifications and the potential consequences of failure it can perhaps be understood why many subsequent fleet destroyers adopted a slightly simplified version of the J class hull form.

Although the variants listed below were all different in detail from the J class, with later models incorporating hard-won war experience, they were essentially J class ships. They all had the same power plant and basic hull form, the same speed and similar main weapons (generally with slightly reduced guns to speed construction and reduce cost). Often anti-submarine capability was increased, along with anti-aircraft armament, and the greater weight made them sit lower in the water (with increased displacement and reduced freeboard).

K Class

The next class to be built after the J class, the K class, were repeats of the J class, except that TSDS was not fitted. There were eight vessels (HMS Kelly as the flotilla leader, with HMS Kandahar, HMS Kashmir, HMS Kelvin, HMS Khartoum, HMS Kimberly, HMS Kingston and HMS Kipling).

N Class

After experimenting with larger destroyers it was decided to revert to the basic J class design. The resulting N class incorporated the modifications already in the J class ships, with a four inch anti aircraft gun replacing the aft torpedo tubes, two additional 20 mm anti aircraft guns and two twin 0.5 inch machineguns. In all apart from HMAS Norman 20 mm guns were fitted in place of the quadruple 0.5 inch machineguns (HMAS Norman was modified later). They were all built with both air warning and air ranging radar.

Eight ships were built, with the Royal Australian Navy receiving HMAS Napier, HMAS Nestor, HMAS Nizam and HMAS Norman, the Royal Netherlands Navy receiving the Noble and the Nonpareil (renamed the Van Galen and the Tjerk Hiddes), the Polish navy receiving the Nerissa (renamed as Piorun) and only HMS Nepal being manned by the British.

Q Class

The Q class combined the armament of the O class with the hull of the J class. They had four 4.7 inch guns, two depth charge mortars, three depth charge racks, one four barrelled pom-pom, six single barrelled 20 mm anti aircraft guns, two 0.303 inch machine guns, and two banks of four 21 inch torpedo tubes. Both air ranging and air warning radar was fitted as standard, as well as asdic. As fewer guns than the standard J class were mounted these ships had increased bunkers at the expense of main gun ammunition, considerably improving endurance.

There were eight Q class ships, which were manned by Royal Navy and Royal Australian Navy personnel ( HMAS Quilliam as flotilla leader, with HMAS Queenborough, HMAS Quadrant, HMAS Quail, HMAS Quality, HMAS Quentin, HMAS Quiberon and HMAS Quickmatch).

Operational Use

Fleet destroyers are designed to act in support of a fleet, providing a screen around high value ships. Prior to the outbreak of the war the Admiralty had emphasised the role of the destroyer in the fleet action. British warships thus spent the pre-war years preparing for 'the next Jutland', although this time the enemy was seen to be the Japanese rather than the Germans.

Whilst the fleet was at sea destroyers were expected to prevent submarines getting in range to attack cruisers, capital ships or aircraft carriers. Once battle was joined they were expected to prevent enemy destroyers closing to engage the larger ships with torpedoes, and (if ordered) to themselves close with larger enemy ships and attack them with their torpedoes. The torpedo tubes carried by destroyers made them a considerable threat to capital ships, and their high speed and manoeuvrability made them difficult to hit with the slow-training main guns of capital ships. However, a single hit from a capital ship was liable to put a destroyer out of action.

Destroyers were also used when larger ships could not be risked, and were described by one British Admiral as being 'expendable'. They were often used for scouting waters which were feared to contain mines, submarines or other hazards, or for work very close to shore (which might expose the ships to increased chance of bombardment or air attack).

The J and K classes were heavily involved in action in the Mediterranean (where most of the losses occurred), although they also served against the Japanese later in the war. Only two of the J class survived the war, with much of the losses occurring before the end of 1942. The K class fared little better than the J class, and again only two survived the war. All the K class losses occurred before the end of 1942.

The Mediterranean represented a particularly difficult challenge as an understanding between Britain and France had allocated the Mediterranean to the French. It was expected that France would neutralise any threat there with their fleet (which was equal to the Italian fleet), supported from bases on the south coast of France. With the French capitulation Britain was forced in to allocating scarce resources to respond to the additional threat, leaving the Royal Navy very stretched across the globe. To make matters worse, the situation in North Africa, the loss of Crete and the basing of German aircraft in Sicily deprived British shipping of air cover whilst exposing them to the attention of the Luftwaffe.

In this environment shipping losses were heavy, and destroyers were especially vulnerable with their lack of armour and light air defence. To meet this threat the air defence capability of all ships was improved rapidly and radar was provided as soon as it became available.

The other variants of the J class had a much easier time as by the time they entered service the balance of power had shifted firmly in the direction of the Allies. With the 'emergency' shipbuilding programme The British fleet had been considerably expanded, reducing the load on individual vessels and allowing more force to be brought to bear at any one time. Technological improvements (most notably HF/DF and radar) had been fitted as standard, thus removing some of the hazardous scouting work from the destroyer fleet and allowing information to be gathered in a much safer manner. Anti aircraft armament had been upgraded and the Axis no longer had air superiority. Only five of the other variants were lost before the end of the war.

The ships served all over the world, more often in fleet work than in a convoy escort role. Elements served in the Pacific, Atlantic, North Sea, Mediterranean, South China Sea and Indian Ocean.