IT is convenient here to set out the way in which the destroyer role in the Royal Navy changed between the time of the turtlebacks and the First World War, because these changes shaped subsequent designs. Other navies did not follow the same path between independent and fleet operations.
War orders issued at the time of the Fashoda crisis with France (1898) give a good idea of the role of the destroyer as then envisaged.1 At this time, the Royal Navy maintained a single destroyer flotilla in commission; most destroyers were delivered, ran their trials, and then went into fleet reserve, as they had no agreed peacetime role. By way of contrast, the French maintained a large active torpedo boat force (called the Defense Mobile) backed by sophisticated all-arms coast defences. This combination posed the possibility, which the British took seriously, of a strike against the British fleet in harbour at or even before the outbreak of war – the sort of operation the Japanese actually carried out against the Russians in Port Arthur in February 1904. As a British officer wrote, the mission of the Defense Mobile could be interpreted flexibly.
‘From the writing of their Naval Officers and the gradual increase in size and speed of their Torpedo Boats, it cannot be doubted that they will attack ships on the English coast or in assailable harbours whenever they may see a chance of success. Their best chance they think will be at the very outset of war, owing to the “slowness of our mobilisation” which they believe to be much inferior to their own.’
The most urgent British wartime requirement was to wipe out the French torpedo boat force. Until mobilisation was complete, the single flotilla of British destroyers would watch the approaches to British ports. French coast defences would make it difficult or impossible simply to attack the French bases, and the French boats could operate out of many other ports.2
The Mediterranean destroyers needed small cruisers to lead them and to back them up. These ships were classed as scouts rather than as third-class cruisers, but both the later third-class cruisers (Gem class) and the scouts were used as destroyer flagships. They were bought like destroyers, requirements being circulated to the likely builders, who created their own designs, HMS Attentive was Armstrong’s version of the ‘scout’ or destroyer leader. She was rated at twenty-five knots, a great deal in 1904, but much less impressive a few years later. Her speed was also too little in comparison with that of the new battle cruisers (she had been conceived to work with much slower cruisers). As the focus of British naval attention turned to the North Sea, the cruiser role changed to one of working with groups of destroyers blockading German North Sea bases. In this view, note the gaff supporting a ‘flat-top’ wireless antenna. The two Armstrong scouts were unique in having four funnels each, all the others having three.
Again, according to the British report, France was well aware that British destroyers would try to blockade its torpedo boats. It hoped that its fast cruisers and destroyers would enable the torpedo boats to break out to cruise the English Channel at night. The British would therefore station destroyers on its own side of the Channel. French boats caught on the English side of the Channel would be relatively easy prey, with tired crews, dirty fires (hence reduced speed) and depleted coal.
The number of British destroyers required should be set by the need to maintain continuous patrols off the two coasts facing each other, with enough reserves at the British ports to keep up the patrols. Destroyers would catch their quarry either near its base or near a British port. No one had any way of conducting open-sea surveillance, so warfare would be concentrated near ports into which ships had to come, or out of which they had to go. Limited endurance made destroyers unsuitable to patrol the open sea, even an area as narrow as the English Channel. Destroyers were clearly disconnected from fleet operations.
Tactics were understood: upon seeing her quarry, a British destroyer would give chase, seeking to stay alongside long enough to inflict sufficient damage either to sink the enemy torpedo boat or to force her to surrender. Thus, upon spotting an enemy boat, the destroyer would leave her blocking position for some time, perhaps some hours, giving another enemy the chance to slip out. The idea that destroyers would work in pairs, and would leave their positions, survived into the era of destroyers working with fleets.
Given the threat of a French torpedo boat attack on a British fleet base, British destroyers trying to enter such a base at night might well be mistaken for French, and fired upon. The system of patrols therefore envisaged havens for British destroyers, into which they could safely come at night: Newhaven, Falmouth, Dartmouth and Dover when its port was finished (Sheerness substituting until then). Destroyer patrols would protect the three fleet dockyards (Portsmouth, Plymouth and Sheerness) and Portland. These could be used as bases for the patrol on the British side, with British destroyers not entering at night. Each of the eight envisaged stations would support a destroyer division.
Destroyer tactics depended on circumstances, which in the 1890s varied radically between the Channel and Mediterranean Fleets. The English Channel was infested with French torpedo craft, to the point where British destroyers had either to clear them out or to blockade them in. Other British destroyers had to cover British ports against possible surprise attacks by seagoing French torpedo craft like Kabyle, shown here in Villefranche (this photograph was received by the US Office of Naval Intelligence on 7 December 1892). By way of contrast, the Mediterranean Fleet would blockade the main French fleet at Toulon, or block the Turkish Straits against the Russians, or try to fight the French in the Mediterranean before the French ships on the Atlantic coast could join them. It had to beat off local torpedo attacks, but in no sense could the Mediterranean be considered infested by torpedo craft – nor could the Mediterranean Fleet hope to block all French torpedo boat bases there. They were just too dispersed. The Mediterranean Fleet therefore developed screening tactics for its destroyers. It operated its destroyers as an integral part of the battle fleet; the Channel Fleet did not.
HMS Foresight was the Fairfield version of the scout/destroyer leader. Fairfield’s was the only version of the scout which had a cruiser-style poop deck. This design had side armour over the machinery and a protective deck at the ends (Cammell Laird had side armour over the engines only, with a protective deck elsewhere, to cover tall the cylinder heads associated with high power and relatively slow running for reliability). The other designs had conventional cruiser protective decks, sloped at the sides. The original requirement was for only six 12-pounders. By 1910, these two ships (but not the others) had had their 3-pounders removed and the 12-pounder armament increased to fourteen such guns. In 1911–12, the scouts were rearmed with nine 4in guns each.
On its north coast, France had twelve torpedo boat stations between Dunkirk and Brest, to which boats would disperse in wartime. Each had to be covered. Experience suggested that destroyers should work at least in pairs for mutual support. The trials of HMS Havock seemed to show that a destroyer could operate at sea for four days, with two or three days in port before going to sea again. Thus continuous patrols required one relief for every boat on patrol, plus some spares to make up for losses. The French ports were grouped into those opposite each of the British bases, the required number of destroyers calculated on the basis of the capacity of the ports. Thus, Sheerness faced Dunkirk (eight British destroyers), Calais (four), and Boulogne (four). Newhaven faced Dieppe (two), Oustreham (two), and Le Havre (eight). Dartmouth faced St Vaast (two), Lezardreieux (two), Cherbourg (eight), and St Malo (six). Falmouth faced Aberwrach (two) and Brest (eight). That amounted to fifty-six, but the analyst who drew up the list thought that thirty boats on duty, thirty for relief, and three spares at each base (four at Dartmouth) would suffice, a total of seventy-three destroyers to watch the French coast. He wanted two patrols (three for Portsmouth), of two destroyers each for each home base (total eighteen), plus five for relief and eight spares: thirty-one destroyers for Home Waters. This total of 104 was nearly a bare minimum, ‘having due regard to the severe nature of the service which blockading entails upon such small vessels … and the necessity of guarding against the danger of being attacked in force’. The 104-destroyer figure helps explain the size of the early destroyer programme, which by this time amounted to about ninety ships. This did not include any destroyers for the Mediterranean (French torpedo boats might attack Gibraltar) or for China.
Given insufficient numbers (eighty-two, not all available at any one time), the Admiralty had to cut back to a total of sixty: at Sheerness, four plus a spare for home waters and eight plus two spares to patrol the French coast; under the Portsmouth Command, four plus a spare for each of Portsmouth and Portland, and eight plus two spares for French waters based at Newhaven; under the Devonport Command, four plus a spare for home waters, and eight plus two spares for French waters at each of Dartmouth and Falmouth. The First Naval Lord worried that British destroyers patrolling their own coast at night might mistakenly fire on their own ships. He much preferred keeping them in port, with steam up, to be unleashed in the event of a French attack. In addition to the destroyers, forces of cruisers and torpedo gunboats operating out of the British Channel bases would cover trade against French attacks and would ‘clear the French flag from the Channel’. All of this was preparatory to bottling up or destroying the French fleet. The war planners took into account the possibility that Russia would enter the war as a French ally, but that did not much affect their arrangements.
The mobilisation and war orders showed no provision for covering a British fleet blockading a French fleet against torpedo attack near the French ports in the Mediterranean, or near Russian ports in the Baltic. Presumably it was considered possible to lie far enough offshore to be immune to torpedo boat attack in such waters. Lists of French ships compiled by the British Naval Intelligence Department did not show Haut-Mer boats in the Mediterranean.3
In August 1899, Admiral Sir John Fisher became Commander-in-Chief Mediterranean. He considered that he had at least as serious a torpedo boat problem as in the English Channel. France had numerous widely-scattered torpedo boat bases, on its Mediterranean coast, in Corsica, and in North Africa.4 Fisher apparently was the first to try to use destroyers to screen his fleet. Manoeuvres near the Levant coast (near Lemnos) showed that a division of eight destroyers on the flank of the fleet was a bare minimum to protect it against torpedo boat attack as it cruised past a torpedo boat station.
By 1899, France and Russia were allied, though they had not yet made arrangements to operate their fleets together. Fisher had to reckon with as many as three enemy fleets: the immediate threat of the French Mediterranean Fleet at Toulon, the somewhat more distant threat of the Russian Black Sea Fleet emerging from the Turkish Straits, and the slightly more distant threat of the French Atlantic Fleet combining with that in the Mediterranean. His source of reinforcements was the British Channel Fleet. On the outbreak of war, he would, therefore, move his fleet from its base at Malta towards Gibraltar or to some other planned rendezvous with the Channel Fleet (which might well be occupied with the French Atlantic Fleet).5 Once near Gibraltar, the initial role of his fleet would be to guard the strait so as to keep the French Mediterranean Fleet from escaping to join the Atlantic Fleet so as to overwhelm the Channel Fleet. He also had to watch (and block) the Dardanelles.
Fisher’s destroyer commanders worked out the implications of his war plans.6 The French probably had forty torpedo boats on the Algerian coast, which was dotted with torpedo boat stations. They would have to be scattered or destroyed or blockaded at least a day before the fleet could safely pass them. Mediterranean Fleet plans issued in September 1900 called for at least sixteen destroyers for this purpose alone. Another division of eight destroyers would accompany the fleet, securing its northern flank against boats from Corsica and southern France. Some might be needed to relieve boats running low on fuel after searching the long Algerian coast. At night this division would form the outpost of the fleet. The fleet would also need a cruiser squadron to observe possible hostile action in the area, and that squadron in turn would need another division of eight destroyers to attack enemy cruisers and destroy enemy torpedo craft in those waters. Another division, consisting of the least efficient ships, would watch the French in the Levant.
In theory, Malta and Gibraltar were defended mainly by torpedo boats. That might suffice for Malta, but the boats at Gibraltar, and the obsolete coast defence ship backing them up, could not shadow a French force passing through the Strait. Fisher’s destroyer commanders favoured a divisional organisation on the ground that eight was the largest number that could work effectively together. A division of destroyers (eight) should be allocated permanently to that role. The planned rendezvous of the two British fleets required a search and covering force of destroyers – perhaps a division from each fleet (sixteen in total). They would suffice only if the Channel Fleet spent no more than one night in the Mediterranean after passing through the strait. That made six destroyer divisions (forty-eight boats). Given the fragility of the ships, the destroyer commanders wanted one spare for each division – one ship at Gibraltar, five at Malta, for a total of fifty-four destroyers (plus another division with the Channel Fleet). In November 1899, Fisher had all of eight destroyers. He and his acting predecessor Rear Admiral Sir Gerald Noel asked for twenty-four.
On 19 February 1900, the Admiralty informed Fisher that in the event of war his force would be increased to twenty-four. That spring another eight destroyers were sent to the Mediterranean. On 12 October 1900, Fisher asked for a total of thirty-seven, and on 25 December, having received his commanders’ report, he asked for sixty-two. Such numbers were impossible while the English Channel and its vital shipping needed the kind of support envisaged during the Fashoda crisis.
Fisher’s demands led to an unusual visit by senior members of the Board of Admiralty to Malta in March 1901.7 As a result of the visit, on 14 March 1901 Fisher was told that as soon as the destroyers were ready he would receive another eight ships (total of twenty-four). His authorised war strength was thirty-two. The Board was not convinced that more were needed, although that could be reviewed as more destroyers were completed, and as the needs of the Channel were finally met.8 Fisher replied with the report of a committee which concluded that the fleet needed fifty-four destroyers, based on its 1901 exercises.
Rear Admiral Reginald Custance, the Director of Naval Intelligence, considered Fisher’s fears exaggerated.9 Why cover the French North African coast when the fleet could steam sixty or one hundred miles offshore, far beyond the range of most French boats? What Russian torpedo craft had to be countered at the Dardanelles? Why bother with a defensive unit at Malta? Surely it would be a waste to keep a division at Gibraltar to await the French fleet, when they could be used offensively instead? Given the current allocation of twenty-four destroyers to the Mediterranean, the Royal Navy had a total of ninety-four accounted for, leaving nineteen (when completed) for either the North Sea or the Mediterranean. Custance could imagine providing another eight to the Mediterranean (leaving eleven, which might suffice until more were built), but no more. He was motivated partly by a belief that the Royal Navy might find itself facing Germany rather than France; Germany had shown its hostility during the Boer War. However, somewhat later, Fisher was allocated forty destroyers, fifteen in reserve in peacetime.
Knowing that he would not receive much in the way of reinforcement, Fisher began to think of a different way to operate his fleet.10 He could not rely on a juncture with the Channel Fleet to gain sufficient strength, or on blocking the strait against the French Atlantic Fleet. He had to deal with each of the threats before they could combine. He realised that crucial telegraph lines crossed Malta, his fleet base, and he arranged to receive copies of the relevant French and Russian telegrams (ironically, both used Malta to avoid interception by the Germans, because the alternative cable route crossed Germany). Fisher realised that he could use the special (signals) intelligence thus gathered, plus what he gleaned from a network of agents, to predict French and Russian naval movements. His fleet could intercept the enemy fleets one by one at sea, crushing them in turn. Interception demanded speed on Fisher’s part, so he worked hard to bring his fleet to maximum effective speed. He was credited with turning a twelve-knot fleet, with frequent breakdowns, into a fifteen-knot fleet without breakdowns – a considerable achievement with vibrating reciprocating machinery. High speed would also make it more difficult for enemy torpedo craft to intercept his fleet, so it transformed his destroyer tactics. The need for speed also interested Fisher in the new turbines, which featured so prominently in HMS Dreadnought.
A fleet intercepting another, rather than blockading it, needed more scouts, because intelligence information and predictions would be approximate rather than precise. Particularly in a pre-radio era, such scouting required large numbers of ships, because information from scouts had to be relayed visually back to a flagship. Since cruisers could never be numerous enough, Fisher became interested in giving destroyers enough seagoing capacity to act as scouts, and not merely to fight enemy torpedo craft or to deliver torpedo attacks.
Tactical notes were issued for the Mediterranean Fleet destroyers in September 1900.11 Destroyers would be organised in divisions of eight, with two sectional (flag) ships. Destroyers would bottle up enemy torpedo boats by day. If they escaped at night, given their limited endurance, they would generally have to return, encountering the blockading destroyers. When engaging enemy torpedo boats, destroyers would try to stay 800 yards distant to avoid torpedoes (the tracks of which would be visible, hence evadable). It would be best to fight on the torpedo boats’ quarter, even though the French were expected to fight while being chased.
When attacking enemy ships, destroyers would work in groups, with a leader. An enemy force would probably have too few cruisers to drive off destroyers keeping touch with it, at maximum visibility distance, during the day. However, daylight attacks were considered suicidal. Towards night, British destroyers would gradually close in. They would strike mainly from ahead, a single destroyer attacking the enemy’s rear to keep him from reversing course as the main attack was delivered. The attack in the enemy’s rear would be the signal for the main attack to begin. Destroyers should form two divisions (in line ahead) to attack, one on the enemy’s bows so that he could not turn away. A single ship would be attacked by two destroyers. The attackers would proceed at dead slow speed, to avoid giving themselves away by the visible foam at bow and stern and funnel smoke and flares. They would accelerate to full speed once discovered by the enemy. The only chance of success would be to fire torpedoes at short range.
It seemed that destroyers would rarely operate with the fleet (although the possibility that enemy destroyers would be present with his fleet was taken into account). If they did work with the fleet, they should stay out of the fleet’s gun range at night, when they might easily be confused with enemy destroyers (at least five nautical miles away from the heavy ships). In a day action, they should remain clear of enemy guns, closing only when all fire from light enemy guns had ceased due to fire from heavy British ships. Destroyers should attack the enemy from ahead so as not to interfere with the gunnery of the British fleet; they should not pass through the battle line (presumably a tactic then being suggested). During a March 1901 exercise, the British destroyers operated on the unengaged side of the battle line, passing through to attack enemy ships. This method proved very effective.
Fisher became interested in alternative ways to operate destroyers in support of his fleet. His biographer, Admiral Bacon, recalled the idea of grouping them with the capital ships, as escorts.12 This idea was impractical, but it suggests that Fisher saw destroyers as vital shields for his battleships. In 1901, he wrote the Admiralty that ‘to steam a Fleet at night without a fringe of destroyers is like marching an army into an enemy’s country without advance guard, flanking parties, or scouts!’ That would give the enemy every chance of success in a torpedo boat attack. He added that his French counterpart (and probable enemy commander) Admiral Fournier said that he would never move without destroyers. How else would he deal with a simultaneous attack by torpedo boats and light cruisers? Night firing would be erratic, and it might not counter even ten boats attacking together. Only fast small craft could fight other fast small craft; mobile forces would always outmanoeuvre slow forces.
Fisher cited the Boer War to argue that weapons could radically change tactics. He saw his destroyers as not merely defensive, but also valuable offensively, in a day action. They could attack during the gunnery battle, and afterwards.13 They could engage and repel enemy torpedo attacks made during the action. Quite aside from any damage they could inflict directly, destroyers could force an enemy to change course by attacking, and thus could support other elements of the fleet. Fisher envisaged a fleet formation in which two destroyer divisions formed a bent screen ahead of the cruisers leading his battleships. Given the speed of his fleet, enemy torpedo craft would find themselves compelled to attack from ahead, much as, four or five decades later, tacticians arranged ASW screens in the expectation that submarines would have to attack fast surface forces from ahead (within ‘limiting lines of approach’). Later cruisers were placed in the screen, with destroyers attached to deal with any torpedo craft which broke through.14 Only cruisers had enough firepower to destroy fast-approaching enemy torpedo craft before they broke through the quickly enough to keep them away from the main body, but only destroyers could run down enemy torpedo craft which did happen to get through. This formation had the important merit of keeping the screen well clear of the fleet, allowing both it and the fleet freedom of manoeuvre. The sort of complete cordon which might have been imagined would necessarily been too close to the fleet (since numbers would have been too limited).
HMS Sentinel was the Vickers version of the scout/destroyer leader. Visible on her forecastle are her three forward 12-pounder guns, arranged for maximum ahead (chasing) fire at the cost of a weaker broadside.
Destroyers would be most effective operating away from the fleet, near the enemy coast, catching his torpedo boats before they got anywhere near the fleet. Any not required for that role could assist the cruisers on the bow of the battle squadron, and destroyers might well be valuable if they kept well ahead of the fleet – outside the range at which the fleet could fire at them.
Fisher’s Mediterranean exercises showed that destroyers could not be bottled up in a port, although they could be watched.15 Their sea-keeping abilities were limited. Night operations were dangerous, because identification was difficult, and gunners sometimes fired on what they thought incorrectly to be enemy destroyers. If allowed to shadow a fleet during the day, destroyers could be depended upon to attack effectively at night, so they always had to be driven off. Sometimes a bright moon which made torpedo attack impossible enabled destroyers to spot the fleet, close in, and attack when the moon set. The ideal destroyer war organisation was by divisions of eight under leaders (third-class cruisers and torpedo gunboats) to facilitate signalling and control. Destroyer operation was exhausting. If destroyers were not going to attack in daylight, it might be possible to place them in quieter areas for rest, and ideally to tow them so as to let their engine room staffs rest. Overall, destroyers could not be relied upon unless supported by fast depot ships.
Torpedo boats, in which the French placed such stock, simply burdened a fleet and always had to be within twenty-four hours of base. As an example of what the French had in mind, Fisher distributed a translated account of a 1901 torpedo exercise against the French Mediterranean Fleet. In February, three groups of boats lay in ambush for a battle squadron consisting of six battleships and three cruisers passing through a choke point, the groups being distributed across the area through which the ships had to come. Each group comprised a leader (a torpedo gunboat or destroyer) and two defence mobile boats. The target squadron steamed with all lights screened, but even so it was spotted by one group at about 4:45am. Without any signal to the other groups, it immediately attacked. The flagship and one other battleship were judged sunk (an attack on a third was disallowed). Boats were reportedly seen only after firing their torpedoes, presumably from the flash of discharge, so one could attack at 328 yards range.16 Any fleet within 200 miles of a French torpedo base was at risk, but the French fleet itself would not take with it to sea any overwhelming torpedo force.
Fisher’s successor (and his second in command at times), Admiral Lord Charles Beresford, added that although wireless had proven very useful in destroyers, he feared that its advent would be an excuse to use destroyers as cruisers and scouts, roles for which they were not well suited. Beresford’s own exercises showed how difficult it was for destroyers to find their targets at sea: a ‘complicated method of search’ by destroyers for a battle fleet near their base failed. Exercises showed that a ship could see the track of a torpedo fired at 1500 yards long enough before it struck that it could generally be evaded. In daylight, destroyers unsupported by heavy fire had little chance of surviving, so in a battle they would have to wait until the two fleets were heavily engaged and the distance they had to cover before launching torpedoes was short. Beresford considered that destroyers working with a fleet could not attack the enemy battle line until the two fleets closed to less than 3000 yards (he thought firing would begin at 10,000 yards – beyond existing capabilities when that was written in 1906). Even then it might be better to hold the destroyers back for night attacks.
In 1905, Mediterranean Fleet cruiser commander, Vice Admiral Baldwin Wake Walker, produced an authoritative study of cruiser and destroyer operation which summarised the situation at that time, as the Royal Navy made the transition from the flimsy turtlebacks to sea-keeping River class and later ships. Increasingly the destroyer was seen as a ‘weak cruiser’, even though ‘to do so is somewhat like employing a racehorse to haul coal’. Wake Walker described the Mediterranean Fleet’s destroyer organisation in eight-ship divisions, ideally of compatible ships, several of which could be combined as a flotilla to operate as a unit.
The key destroyer characteristics were mobility (under favourable conditions), invisibility, and shallow draught. Against those were small coal capacity, hence limited radius of action (which might be alleviated by using a mobile base).18 The single executive officer necessarily focused on ship or flotilla handling, so he might often fail to see many things of utmost importance to a cruiser. The low and unsteady bridge made a poor lookout position. The small signal staff could not hope to excel at the long-range signalling so vital to a cruiser. A destroyer was rarely certain of her position, a vital consideration in scouting or patrol work. Destroyer success in such work came at the cost of exhausting officers and crews. Given a limited number of stokers, the destroyer would inevitably be exhausted in a lengthy chase.
Within a fleet the destroyer role depended on whether the fleet was cruising or fighting. While cruising, it could expect torpedo attack only at night, because torpedo craft approaching in daylight would be destroyed before they reached attack range. Wake Walker repeated the argument that a fast fleet had to fear attack only from ahead. A torpedo force making a concerted attack could not be relied upon for speeds above about eighteen knots for destroyers, or sixteen knots for torpedo boats. Otherwise the attack might fail because some units would not be able to maintain speed, and all needed a speed margin to maintain formation. These were not of course the speeds used in the final rush, but they determined the lines of approach. Thus a fleet steaming at fourteen knots was vulnerable only over a forty-five degrees arc on either bow. These considerations help explain Admiral Fisher’s fascination with high fleet cruising speed, although he had many other factors in mind.
A slow (about ten knots) fleet could be attacked from all directions. In some recent exercises, attacks from the quarter succeeded because watches concentrated too much on what they considered more probable directions. There would never be enough destroyers to screen a fleet in all directions from a sufficient distance, so some alternative was needed.19 For Wake Walker, it was a pre-emptive search of the enemy coast near the track the fleet would follow at night, in hopes of driving off lurking torpedo boats and keep them out of range of the fleet. Destroyers could keep enemy torpedo boats so busy that they would lose all accurate reckoning of their positions, hence would be unable to act on whatever attack information they had.
Whatever the fleet speed, attacks from ahead were best because they limited the time during which the attackers would come under fire: they would close the range at the maximum speed. Too, a bow attack was least affected by errors in estimating target speed. From all other directions, mis-estimates caused worse problems. In Mediterranean exercises in which the fleet streamed its anti-torpedo nets, that is, steamed relatively slowly, all the torpedoes, fired from the side, passed ahead of the targets because their speed had been overestimated.
Destroyers screening a fleet should operate at a fixed distance from the heavy ships, probably five nautical miles (and never less). This distance would give the fleet ample notice of torpedo attack and freedom to fire in any direction freely. All ships in the screen needed a simple recognition signal (lights). Wake Walker estimated that the minimum fleet screen was two destroyer divisions, using a second-class cruiser as their support and guide ship.20 The guide ship would be responsible for maintaining distance from the fleet, which in turn would ensure against blue-on-blue attacks. Individual destroyers could not be expected to keep station, but the larger units working with them could. When enemy torpedo craft were spotted, pairs of destroyers would immediately give chase, switching on their recognition lights. When chasing, destroyers would soon lose their reckoning; they needed a fixed point (such as a supporting cruiser) on which to rally.
Supporting ships were particularly valuable when a destroyer division masked an enemy base. Scouts and torpedo gunboats could help cut off returning enemy ships. Their presence allowed destroyers to range over a much wider area. They could also keep enemy light craft from driving off or harassing the blockaders.
Battleships’ anti-torpedo boat guns tended to be unprotected for two reasons. They had to manoeuvre quickly to deal with their agile targets, and they needed the highest possible positions. During a gun action they could not be manned. Only the fleet’s destroyers and cruisers could beat off such attacks.
Admiral Fisher became interested in torpedo craft, both coastal torpedo boat destroyers and submarines, to defend the British coast against enemy forces which might cross the North Sea undetected. Light cruisers could provide such units with effective ‘eyes’, HMS Boadicea was conceived for this role.
The fleet’s own destroyers would operate on the unengaged flank of the fleet, awaiting either enemy attacks or the opportunity to press home their own attacks on the enemy ships. There was a risk that British destroyers attacking in the space between their own and the enemy’s battle line would hamper their own ships’ fire.
It was not clear how effectively destroyers could attack an enemy fleet at sea. Fast enemy ships would be comparatively immune from attack because the arc from which attacks could be mounted was so narrow. British experience was limited to peacetime manoeuvres, and the lessons of the Russo-Japanese War were not yet clear. Before Tsushima, Japanese experience had been disappointing, despite their unquestioned skill and daring. Wake Walker suggested that without experience firing torpedoes at moving ships, the Japanese had not learned to judge target speed. They lacked divisional structure in their flotillas, and had no means of communication between flotilla commanders and cruisers in support. It was far better to attack in subdivisions or pairs than singly, not least to saturate defences.
To get into the right position a destroyer needed information from the more distant units which had a clearer picture of the tactical situation. The cruiser leading the flotilla could collate that information properly, placing her destroyers in position to see the enemy fleet before dark. After dark she could stay in contact with the enemy fleet, firing guns and rockets and by using her searchlights to indicate the enemy course if the destroyers lost track.
Because of their poor navigation, destroyers should always obtain a position (latitude/longitude) before leaving a fleet. No destroyer should leave a fleet or an escorting cruiser for a rendezvous without obtaining the course and distance of the same, unless certain of her position. A supporting cruiser had far better navigational facilities. In several Mediterranean exercises, destroyers unaware of the overall tactical situation were captured even though a superior friendly cruiser force was within easy reach when the enemy gave chase.
Wake Walker recognised how crippling the lack of IFF would be. Presumably echoing standing orders, he wrote that destroyers should never close a friendly ship or fleet at night without direct orders, and before the fullest recognition on both sides had taken place. If the ship or fleet was moving, the destroyer should approach from astern, taking the greatest care that no strange craft was nearby, waiting to take advantage of recognition signals to attack. Officers had to make sure that their targets were not only not friends, but actually enemies – as many others would later learn to their regret, ‘do not forget that neutrals exist’.
As envisaged in 1902 war orders, the single Home Fleet (wartime successor to the peacetime Channel Fleet) had the very different problem of neutralising the torpedo boats and destroyers which might swarm out of the French Channel ports, although it also had to prevent any combination of the Russian Baltic Fleet with the French Northern Fleet.21 The four home destroyer flotillas, based at Plymouth, Portland, Portsmouth, and the Thames (Sheerness or Dover) were expected, as before, to deal with the French destroyers and torpedo boats based on the French Channel coast. They were not to be detached on other service.
Relatively slow cruisers became inadequate leaders when destroyers were integrated with the main British fleet from about 1911 onwards. They had to stiffen attacking British destroyers (slower cruisers could beat off enemy torpedo attacks). Thus in 1913, the Royal Navy became interested in destroyer leaders. Although converted into a minelayer, HMS Abdiel retained her original appearance, with a destroyer-style open bridge atop her chart house.
sA formal war organisation for the large force of destroyers in Home waters was first set up in August 1902. Prior to that date the three instructional forces were under the separate commands of their own port commanders, and there was no set plan for the war role of the large force of reserve torpedo gunboats and destroyers. In 1902 a senior destroyer commander was appointed to command the whole force in wartime under direct Admiralty control; he was also responsible for peacetime training. This officer, Captain Dicken, commanded the British (Blue) side in the first torpedo manoeuvres (1903), as that would be his wartime role. The manoeuvres tested the effectiveness of destroyers trying to neutralise torpedo boats when both operated in narrow waters (as in the English Channel) near their bases. Because the Royal Navy had too few torpedo boats, some destroyers simulated them. The manoeuvres also in effect tested the new River class (see below).22
Early in 1904, arrangements were changed to place the force under a junior captain responsible to the C-in-C Home Fleet rather than to the Admiralty (which retained responsibility for preparing the force for war).23
The 1904 torpedo craft manoeuvres envisaged a superior (ie, British) fleet moving within the operating radius of a strong enemy torpedo force. This Blue fleet had superiority in cruisers and battleships, and its own torpedo flotillas.24 Blue used a destroyer screen at sea, far enough from the main fleet that any approaching torpedo craft the fleet encountered had to be hostile. The Red commander found such screening irrelevant, because his torpedo craft could not find the Blue fleet in the first place. The Blue battleships were saved not by their escorts but by their freedom of manoeuvre and by their small number, which made Red searches difficult. An attempt to blockade Red ports, to keep torpedo craft from coming out, failed altogether. The torpedo gunboats, which had been re-engined and reboilered, provided useful support for British destroyers attacking enemy destroyers and torpedo boats.
Destroyer command arrangements were changed again in February 1905, when Rear Admiral Winsloe was appointed Admiral (D), responsible for all destroyers, torpedo boats, and submarines in full commission and in commission in reserve. An Admiralty letter explained that control under one officer was essential so that movements of such ships should keep them from meeting British ships at night, when they might be fired upon, and might accidentally make attacks of their own. Without such arrangements individual commanders might not fire torpedoes for fear of attacking friendly ships. Moreover, the safety of the British fleet in the Home area required that the French torpedo craft be bottled up.25 Unless all of the British torpedo craft were controlled by one officer, ‘their effort will be frittered away… There is no class of vessel that requires to be so carefully nursed as Destroyers, both as regards Machinery and Personnel, if they are to be at their best when really required.’ Success of any major operation in the English Channel or in the North Sea required full co-ordination of all fleet resources, including torpedo craft. Torpedo gun boats and, if necessary, scouts would be assigned to work with the destroyers. About 1907, Admiral (D) was redesignated Commodore (T) to emphasise his command over all torpedo craft, including submarines (which were increasingly capable of operating well out to sea). In about 1912, responsibility for the the defensive flotillas was further split off under a Rear Admiral of Patrols.
Reorganisation coincided with the beginning of a shift of emphasis from the Mediterranean to the North Sea, as the British increasingly saw Germany rather than France as the most likely future enemy. French torpedo craft had made the English Channel nearly untenable by a battle fleet, and Fisher seems to have seen the North Sea in much the same way. Submarines complicated the situation, because even more than destroyers they could not be bottled up in their bases. Successive British strategists, such as Fisher’s successors, hoped that the submarines’ limitations could be used to make the fleet survivable in part of the North Sea. For example, exercises suggested that submarines generally found it easiest to intercept their targets near bases, so once an anti-submarine weapon was devised, it could be used by special forces screening the fleet as it entered and left port. High fleet speed was seen as a tactical countermeasure. The important lesson of successive manoeuvres seemed to be that the fleet as a whole could operate in the North Sea on only a transitory basis. It could not closely blockade Germany.26 Yet it had to counter the German fleet, or any German surface force which might cover an invasion of the United Kingdom, a major British government fear of the period.
In effect, First Sea Lord Admiral Fisher translated the typical Channel strategy, emphasising a destroyer blockade of French torpedo boat ports, into a new North Sea strategy. Unlike the main fleet, destroyers could, it was thought, blockade the German coast, the theory being that they were less vulnerable to torpedo attack than capital ships. They would be backed by shorter-range torpedo flotillas built around submarines and the new coastal torpedo boats (ex destroyers) on the British coast. The blockading destroyers would sink German destroyers emerging from port, just as in the past destroyers off the French coast had been expected to run down French torpedo boats and destroyers as they emerged. As an indication of the new concept of operations, distant blockade – a run out to a distant station, operation there, and return to base – became a criterion for destroyer engineering performance. Implicit in the new strategy was that destroyers would no longer work with the fleet.27
When Fisher’s Mediterranean successor, Admiral Lord Charles Beresford, took command of the Channel Fleet in 1907, he apparently expected to bring his Mediterranean destroyer tactics with him. He was appalled at the new orders, which stripped his fleet of destroyers: how could his fleet survive in the face of German destroyers?28 As late as February 1908, a destroyer officer lecturing at HMS Mercury, the signal school, continued to talk in terms of fleet destroyer tactics, but by then they had been dropped.29 After a hot fight, Beresford got his destroyers – but only twenty-nine, out of a total of 242 in Home waters.30
Fisher’s new operating concept might have been connected to his increasing interest in central (Admiralty) control of deployed forces, based mainly on large-scale Admiralty plots fed by a combination of intelligence and reports from the fleet. The new system dramatically reduced the independence of senior officers at sea, particularly in the North Sea, and it may be that Beresford’s attacks on Fisher’s reorganisation reflected more his fury at losing his normal prerogative than his espousal of the tactics that Fisher had invented in the first place.
In 1907, Captain G A Ballard proposed a war strategy of Fisher’s type. Its object was to force the Germans into a decisive battle on the far side of the North Sea (from Germany), where they would not benefit from the considerable German investment in mines and torpedo craft. Ballard envisaged blocking the northern and southern exits of the North Sea (as the Royal Navy did during the First World War). The Germans would be compelled to come to sea to break the blockade. Destroyers in the North Sea would detect them. Given the warning they raised, the British battle fleet would intercept them. This was not too different from what had been done during the 1885 manoeuvres, albeit on an infinitely vaster scale: torpedo craft near the enemy would trigger interception by heavy ships further away. Other torpedo craft based on the British coast would backstop against any German invasion, until the fleet could intervene.
War plans issued in January 1911 called for an initial inshore watching force of four armoured cruisers, two destroyer flotillas, and two sections of submarines under Commodore (T).31 Also in this force would be three minelayers. A third destroyer flotilla might be released from patrolling the English and Scottish coasts (which would be mined upon mobilisation) to reinforce or relieve the other two. The inshore operation would keep the Germans from breaking out, and it would also give the British destroyers experience of German inshore waters. The British force would capture or destroy enemy destroyers; if it failed to catch one, it would report its destination and direction so that it could be intercepted further out to sea. As many destroyers as possible would be massed on the German coast at the outbreak of war, even if many would soon have to be withdrawn to fuel.
New war orders issued in April 1912 formally cancelled the idea of close blockade of the German North Sea coast. They envisaged a deployment which would keep the British battle fleet out of reach of a surprise German attack (ie, by destroyers crossing the North Sea at night) yet close enough to intercept a German sortie. Thus the fleet would split into a northern component (four battle squadrons) at Scapa Flow, Rosyth, or Cromarty or at sea and a southern component (two older battle squadrons) assembled at Spithead or Portland – which was much the way the British arranged their force in 1914. This fleet would be covered by an arc of cruisers and destroyer flotillas, the wings of which would be on the Norwegian and Dutch coasts. In contrast to the assumption made in the 1912 and 1913 fleet exercises, the war plans warned that war would probably break out suddenly, with no more than forty-eight hours’ warning, in which case the first priority would be to assemble a strong enough fleet to face the whole German Navy. All cruisers and destroyers on the East Coast would form a protective cordon while the northern and southern fleets formed and deployed. Moreover, if war broke out suddenly, it would be because the enemy had ‘some great enterprise [ie, invasion] in mind which will be launched almost simultaneously’.
This was Ballard’s concept of operations, with no attempt being made to keep the Germans in their ports. Instead, they would be intercepted in the North Sea, based on information from watching ships. These orders envisaged a triple line. The patrol line and flotillas closer to the German coast would be strong enough to handle any but the most serious enemy movement. They would be backed by an observation line which would trigger the main fleet (the third line). All of this force was in addition to the cruiser force blocking the northern entrance to the North Sea, thus blocking shipping headed to Germany. The war orders allowed for two possibilities, war against Germany without allies, and war in alliance with France. In the latter case, the passage of the expeditionary force across the Dover Strait would be covered.
Meanwhile, as described below, destroyers were being integrated back into the fleet. For them there was a vast difference between blockade in the North Sea, near or far from the German coast, operations with a fleet triggered by observers in the North Sea, and fleet sweeps. Ships on blockade duty were relieved periodically. They needed enough endurance to cross the North Sea, stay there at low speed for a few days, and return. Similar endurance might be enough for a quick sprint half way across the North Sea with the fleet to intercept the enemy fleet. A sweep, however, would last longer, and it would require much longer destroyer range. As the standard type of British destroyer evolved through 1914, it carried with it the heritage of the blockade concept of operations. When the situation changed late in 1913, the war planners suddenly realised that the destroyers also had to change, but there was no time for that to be done.
The Beagles, Acorns and Acastas were conceived as elements of independent destroyer forces, mainly on blockade duty in the North Sea. In the day they would attack emerging German destroyers; at night they would concentrate on attacking enemy ships emerging from harbour (but the C-in-C might direct that they do not attack these ships). The 1910 British destroyer handbook explained that the primary destroyer role was to watch, attack, and destroy enemy torpedo craft (including submarines) as they emerged from their ports. Destroyers would search the enemy coast to find torpedo craft hiding there. The destroyers would strip Germany of its torpedo arm and superior British gun power would destroy the German fleet.
In 1910, the ideal British flotilla consisted of a leader (a cruiser carrying the commodore or senior officer) and two squadrons, each led by a scout (ie, a small cruiser). Each squadron was divided into two divisions, each of three subdivisions (two destroyers each), for a total of twenty-four destroyers. If the flotilla had more ships, it could be split into more than four divisions. The squadron was the tactical unit, its strength set by the standard German tactical unit of eleven destroyers, including a leader. Given her firepower, the scout was seen as the primary destroyer-killer, the squadron engaging any enemy craft which escaped her. For a night attack on surface ships, the squadron’s scout located the target formation, guided destroyers to within touch of the enemy, assisted them in keeping in touch with each other and with the enemy, and supported them in action with her gunfire. Before nightfall the scout would provide the destroyers of the squadron with the position and probable movement of all vessels, friendly and enemy, during the ensuing night. She would also set up a post-attack rendezvous. She was expected to inform the nearest cruiser and destroyer squadrons of the enemy’s approximate strength and course should he break through the squadron. Particularly after a fleet action, the squadron might track, locate, and attack the enemy fleet or ships at sea.
Destroyers might also form surface strike forces. Ideally they would remain at their base until the enemy was located, then go straight to the enemy. That was, however, unlikely, so the destroyers would steam to a fixed rendezvous well clear of the line of friendly cruisers watching the enemy coast (to avoid friendly fire) but also close enough to the likely enemy position at nightfall.
The largest tactically cohesive unit, which might attack together, was the six-ship division, in a single line to avoid masking fire. Invisibility was the key to a successful night attack against major enemy ships. Ships would maintain moderate speed until discovered to reduce their visible bow waves and to avoid flaming from their funnels. The division would seek a position ahead of or on the bow of the enemy (in some weather, however, it would be best to attack from the quarter). It would break into sub-divisions attacking at short intervals, separated far enough that no single searchlight could illuminate more than one sub-division, or one shell damage more than one ship. Once discovered by the enemy, the ships would accelerate to full speed, seeking to fire from 200-yards range (longer-range torpedoes were about to enter service). Having fired, destroyers would put their helm hard over to escape, not crossing the enemy’s bow to avoid the risk of collision.
Meanwhile, the destroyers’ primary weapon, the torpedo, was changing radically. In January 1904, the DNO proposed convening a committee to consider development of a new fast long-range torpedo.33 Now that gyroscopes could ensure straight-running, propulsion was the only limit to torpedo range. Presumably the DNO was interested because effective gun range was increasing dramatically. The Committee pointed out that heating the air in a torpedo would increase its range. By 1907, the Royal Navy was interested in burning fuel to add energy to the air, in effect converting the torpedo power plant into an internal-combustion engine. That autumn, a prototype heater torpedo was ordered. Whitehead delivered two 21in torpedoes about June 1908, followed by two from the torpedo section of the Royal Gun Factory (later the Royal Navy Torpedo Factory) a few months later. In June 1908, in advance of trials, the DNO asked that the 1908–9 destroyers be modified to carry two such torpedoes.
First World War weather experience caused modifications: HMS Ithuriel shows an enclosed wheelhouse (the highest bridge level in Abdiel) with an open bridge atop it. The forefunnel was raised to limit smoke on the new bridge. Otherwise Ithuriel shows the layout planned for the leaders before the war. Compared to destroyers, she had an extra 4in gun and, more importantly, a great deal more fuel. In 1913, the War Staff seriously considered making such ships the standard destroyers, because they alone had the endurance to work with the fleet.
(NATIONAL MARITIME MUSEUM)
The heater had revolutionary impact. In effect it restored what the gyro had achieved a few years earlier, giving the torpedo much the same range (at this time greater range) as the gun.
The first (short) 21in heater torpedo (17ft 10½in long; 2100lbs) was expected to carry a 225lb warhead to 7500 yards at thirty knots or to 1000 yards at fifty knots, based on trials with experimental RGF torpedoes. It armed the Beagle class. Lengthening the torpedo to twenty-three feet could add about 100lbs to the warhead, and could extend range to 12,000 yards at thirty knots – to battleship gun range. Assistant Director of Torpedoes Currey remarked in December 1908 that the threat that a fleet could fire a torpedo broadside into the centre of the opposing fleet could force the latter to maintain longer ranges favouring the British (who had superior fire control). These would be ‘browning’ shots, apparently named after the use of shotguns to ‘brown’ a covey of birds. Although aimed at the centre of the enemy line, they were unlikely to hit that particular ship. However, they had a good chance of making hits against some of the closely spaced ships in the enemy battle line.
As before, it was assumed that destroyers would run in to fire their weapons at short range against chosen targets. Thus initial thinking emphasised the high-speed short-range setting for destroyers, which would give them a better chance of hitting, and which might enable them to fire at safe range during a day gunnery action. It might be worthwhile to integrate destroyers back into the battle fleet. In March 1909, Currey argued that it was now worthwhile for destroyers to carry spare torpedoes, so that they could fire and reload during a battle. As far as Currey knew, no foreign power had comparable long-range torpedoes. The DNO, Bacon, thought that the Royal Navy could soon have torpedoes which effectively outranged guns. He supported the reload proposal.
Trials in June 1909 gave 10,300 yards at thirty knots and 5000 yards at 42.5 knots, with 2000 yards at fifty knots considered certain once some depth-keeping problems were resolved. The DNO decided that the new 21in torpedo should be twenty-two feet long, carrying 280lbs of high explosive, with thirty- and fifty-knot settings. He wanted the torpedoes adopted for, among other ships, the 1909–10 destroyers (Acorn class). In peacetime, the two spares would be carried on board a depot ship to avoid exposing them to the weather. In wartime they would be carried on board the necessary fittings having been installed. Existing 18in torpedoes were reworked and new torpedoes designed. The new RGF 18in Mk VII and Mk VII* could be set for 3000 yards at forty-one knots or 7000 yards at thirty knots, and they were expected to receive a third shorter-range forty-five-knots setting. Heater torpedoes would be supplied only to River class and later classes of destroyer (six per ship, most of the torpedoes being held at depots).
At about the same time, in connection with the Acorn design (September 1909), it was proposed that torpedoes be fired from the fore bridge rather than from the tubes. In addition to some Acorns, equipment was installed in some River, Tribal, and Beagle class destroyers (it was first approved, in December 1909, for the Beagles). Torpedoes were ejected by a powder charge, which was fired remotely. Despite some misfires, the system worked. It was an alternative to voice communication with those at the tubes. Having selected the target, the CO could make sure his ship fired at the right one. Voice messages often arrived in distorted form. Remote firing was criticised because of possible errors due to the separation between bridge and tubes, and it was eliminated in 1911. Such parallax errors were negligible at the much longer ranges later envisaged, and in 1916 remote firing was revived. This time it used electro-pneumatic gear similar to that used by railways to control signals and points remotely.
By this time, the Royal Navy was receiving repeated reports that the German Navy was incorporating torpedo boats into its own battle fleet. The Germans practiced a showy manoeuvre in which destroyers on the unengaged side of their battle line passed between their battleships to attack the enemy battle line during the gun action between the two lines. Initially, the British reaction was derisory. It would be far more efficient to attach destroyers to the van or the rear of the fleet, to disrupt the enemy line by concentrated attacks on his van or rear. Destroyers venturing into the space between the two fleets would make few hits, and would probably be wiped out. Further reflection suggested, however, that by their attacks the German boats could disrupt the British formation. At this time gunnery effectiveness so clearly depended on steady steaming that the German torpedo tactic could be read as a tactical gunnery countermeasure. Moreover, British battleships had their anti-destroyer guns in the open, typically atop their turrets, where they could not possibly be used during a gun action. Among the British reactions, then, was to switch to protected hull positions and also to heavier secondary battery guns, beginning in the Iron Duke class battleships and battlecruiser equivalent, HMS Tiger.
The British, too, had envisaged using their destroyers in day actions, but this idea had been abandoned. Now they wondered whether it should be revived (it was treated as a new idea, but it had been dropped only about five years earlier). How should destroyers operate with a fleet? In 1909–10, Home Fleet commander Admiral William H May conducted exercises.34 In wartime, given their limited endurance, destroyers could operate with the fleet if they returned to base every two or three days or if action were imminent. The limit would be strain on their crews. They could be replenished at sea, particularly with oil in ordinary weather. However, the IFF problem which had complicated past attempts to integrate destroyers with the fleet had not been solved: it was difficult to imagine how destroyers could be stationed at night so as not to endanger their own side. Simply knowing that his destroyers were nearby would hamper the fleet commander.
May reflected earlier thinking, regarding fleet destroyers mainly as a means of sinking ships disabled during the gun action. Only if weather was misty (visibility less than 8000 yards), could they get close enough to an undamaged and unengaged enemy fleet to attack it before the gun action. As they emerged suddenly from the mist, the destroyers would make browning shots at about 3000-yards range (which was available from the new torpedoes).35 Early destroyer attacks were unlikely to succeed if the destroyers could be seen at much greater range. An early attack might disrupt the enemy fleet as it formed its cruising columns into single-line gun battle formation. During that manoeuvre, the enemy fleet could not turn away to evade browning shots by the attackers. He would rely either on counterattack by his own destroyers or on his battleships’ fire – in which case the battleships might be unable to engage the opposing British battleships. At the least, dreadnoughts would have to assign one turret to anti-destroyer fire, reducing their effective broadsides. Once the fleets were engaged, destroyers might successfully attack, because the enemy battleships would be concentrating their efforts on the British battle line, and small ships might not even be too visible in a haze of gun and funnel smoke. Running at maximum speed, destroyers might well survive until they fired. Again, May envisaged browning rather than short-range aimed shots. To avoid being sunk (wasting their torpedoes), destroyers should be able to fire as soon as they came under enemy fire. If a fleet had already formed, its battleships could turn away together – but that might well lead to great confusion.
Once the battle had begun, destroyers approaching the enemy fleet had to pass through a danger zone extending from 1000 yards in front of the British line to 2000 yards beyond it, but they would be fairly safe from attacks by enemy light cruisers. A run from the end of the British line would place destroyers in the danger zone for longer (nine minutes in the worst case), but it would hamper the British line far less than the pass-through.
To solve the IFF problem, May proposed that by day the destroyers should steam astern of the battle fleet, getting maximum rest before action. Alternatively, they could steam entirely apart, a rendezvous having been arranged. With action imminent, a squadron of destroyers could be stationed on either flank of the battleships (beam or quarter), with orders not to hamper the main fleet when it changed from cruising to battle formation. The best position would depend on whether the commander wanted an early or late attack, based on weather. To reserve destroyers for attacks once the action was fully developed, destroyers should occupy unexposed positions, for example on the unengaged side of the battle line.
If action was already general, May concluded that the destroyers should be kept on the unengaged side, say 2000 yards off, until directed to attack. They might pass through gaps between divisions (the Germans passed between ships) or they might attack from the head or tail of the British line. In the latter case a well-placed cruiser at one end of the enemy line could pour fire into the destroyers as they approached.
Destroyers working with the fleet were hardly ideal anti-destroyer ships. In the blockade role, they needed their speed to run down escaping enemy craft, but in a fleet action the enemy’s destroyers would be coming towards ships trying to stop them. Gun power would be more important than speed, so small fast cruisers, with much more firepower and better vision from higher bridges, would be the best counters. However, if the enemy fleet had enough destroyers with it, there might not be enough cruisers, and the mass of British destroyers would necessarily make up the difference.
Given the new heaters, battleship torpedo range now roughly equalled effective gun range. May wondered if it would be worthwhile to risk destroyers in a day action when the battleships themselves offered more torpedo firepower.
The pre-1914 Royal Navy was intensely interested in destroyer minelaying as part of fleet tactics. During the Russo-Japanese War Japanese destroyers sometimes laid floating mines in the path of the Russians. By 1912, the Royal Navy wanted to do the same. That project died, but it seems to have convinced Admiral Jellicoe, the wartime British fleet commander, that the Germans would surely do what the Royal Navy wanted to do. When the British did convert destroyers and light cruisers for minelaying (HMS Abdiel is shown alongside the light cruiser Aurora), the intent was rather to carry out quick missions into nominally German-controlled waters, particularly to deal with the U-boats and destroyers raiding British shipping in and near the English Channel. By 1918 the British were using acoustic and magnetic mines.
May concluded that the role of destroyers working with a fleet was first to attack with torpedoes and only then to frustrate enemy destroyer attacks. Cruisers and scouts were better anti-destroyer weapons in a fleet context. Given long torpedo range, destroyers should never fire towards their own fleet. Nor, once separated, should they ever close the British fleet if they could possibly avoid doing so, because the battleships would fire at them. Instead, destroyers should return to base after attacking; destroyers should never stay with the battleships after dark, because the battleships would fire indiscriminately.
In 1911–12, there was a general discussion of destroyer roles, which would affect destroyer design. The implication of May’s exercises was that destroyers operating with the fleet needed heavier torpedo armament, at the least twin tubes rather than single tubes plus single stowed torpedoes. It could even be argued that guns should be traded for more torpedoes. May’s successor, Admiral George F Callaghan, argued that torpedo attack supporting the fleet was the single most important destroyer mission, hence that torpedo armament should be emphasised over guns. Like May, he considered light cruisers his best defence against enemy torpedo attack. The Board swatted him down. In line with earlier thinking, it held that the primary destroyer role was to kill enemy destroyers in the North Sea while operating independently off German destroyer bases. German coal-burning destroyers had even less endurance than their British counterparts. The German fleet might take some to sea with it, but they would have to return to port quite soon for reliefs. British destroyers off the German coast would pick them off as they came and went, much as, four decades later, NATO envisaged submarines in choke points picking off Soviet submarines as they returned to their bases for fuel and torpedoes.
Callaghan envisaged deploying his fleet destroyers on the unengaged side of his line, half ahead on the beam and other half astern on the quarter. Whichever way the enemy line approached, half would be in position to attack. For Callaghan, light cruisers were the antidote to enemy torpedo attack. Destroyers should be used against the enemy’s battle line.36 New destroyers should be armed more heavily with torpedoes, their designs placing less emphasis on guns. Now Director of Operations Division (DOD), in 1907 war planner Admiral G A Ballard (soon to become Admiral of Patrols) thought that submarines were rapidly assuming the torpedo attack role; some foreign powers (presumably Germany, and possibly the United States) advocated using both destroyers and submarines with their battle fleets. Once fleet submarines became available (the British were working on one), surely destroyers should concentrate on killing other destroyers, as submarine torpedoes seemed unlikely to be effective in that role.37 For the moment, Callaghan might be right for those attached to his fleet, but most destroyers would concentrate on keeping German torpedo craft from entering the North Sea. The Admiral of Patrols, the old destroyer officer Admiral John de Robeck, saw a choice between building many more destroyers, perhaps limiting the number of guns to add ammunition, or building a new kind of lightly armoured cruiser of great speed’ specifically as a fleet destroyer-killer in the proportion of one to every three or four destroyers. This was presumably the rationale of the contemporary Arethusa class light cruiser.
In this context, the 1913 manoeuvres were a shocking surprise. They showed that it was impossible for a watching line of ships, mostly destroyers, to be sure of intercepting, or even seeing, an invasion force crossing the North Sea.38 An actual German attack on the British coast, such as the December 1914 bombardment of Hartlepool, would risk being cut off on the way home. It seemed to follow that the Germans would not raid the British coast unless that offered the very largest payoff, a successful invasion. In both the 1912 and the 1913 manoeuvres, therefore, the object of Red was invasion. In both cases he succeeded. Blue was unable to prevent raids and landings, and could never quite bring Red to action. The British fleet commander commented that to draw the natural conclusion, that the primary role of the fleet was to prevent invasion, would have been a disastrous surrender of the initiative at sea.
Callaghan argued that the German fleet was the single objective. Once it had been killed, British trade would be safe, and German trade effectively blocked. No one imagined that submarines would attack merchant ships directly, because that was directly contrary to treaties which the Germans had signed. In Callaghan’s view, the fleet would best be placed to act if it cruised well offshore in the northern part of the North Sea. The British would have the initiative: the Germans could either fight or accept the loss of their trade and their colonies. The last thing the British wanted was a general action near the German coast, where they were strongest. The further from base the battle was fought, the more depleted the British destroyer force. A British fleet fighting near the German coast would also lose the support of ships (coast-defence flotillas) stationed on the British coast, which would help overwhelm the Germans and would harass them after the action. On the near side of the North Sea, moreover, the British fleet would be outside (it was hoped) the effective ranges of German submarines and destroyers, and also out of sight of his airships. Experience during the manoeuvres suggested that the fleet was safest well away from the coast, where submarines could not easily find it. They would loiter in places the fleet was likely to pass or approach, such as the Forth, near the Dogger Bank, between Swaarte Bank and Terschelling Light, and in and near the Moray Firth. These places figured prominently in First World War naval combat. In the 1913 manoeuvres, a British inshore squadron (off Flamborough Head) was ‘perpetually troubled by submarines’. Such operations ‘need special consideration owing to increased liability to such attack’. Aircraft could sometime spot submarines, but they could not yet attack them. The first destroyer ASW weapons, explosive sweeps (see below), were still experimental.
The 1913 manoeuvres assumed that a period of strain preceded the outbreak of hostilities, the British fleet assembling at its war base – which had to be protected against possible surprise torpedo attack (such as the attack that Japan mounted against Port Arthur in February 1904, and which the Japanese had failed to follow up vigorously enough). The British fleet commander also observed presciently that the Royal Navy could not go on the offensive if the Germans remained in harbour. It was already clear that close blockade was impossible, and the Germans had Zeppelins to provide them with fair-weather surveillance of their own.
The British fleet had to intercept the German fleet at sea. That seemed to demand a line of observing ships stretching from coast to coast across the North Sea, far enough from the British base to ensure that the fleet could reach the Germans in time. In effect, the 1912 and 1913 manoeuvres showed that the British lacked the means to do that. During the First World War, British naval strategy became possible mainly because the British replaced the line of pickets with radio intelligence (and, late in the war, by submarines closer to German bases). In 1913, the only viable pickets were cruisers, but the British had too few.39 New light cruisers became a priority, although the current design, conceived more as a destroyer leader, was too small, hence too easily limited by weather conditions. Callaghan wanted cruiser numbers in the North Sea quadrupled but building more cruisers would be at the expense of destroyer production.
Given the paucity of cruisers, the Germans successfully raided the British coast, landing notional troops. The British had imagined that, weakly escorted, a raid could be dealt with by the patrol flotillas and by a cruiser squadron. However, the 1913 manoeuvres showed that even a weak escort could cover an enemy force against anything short of battleships. In war, the patrol flotillas would have to be backed by old battleships
– as they were during the First World War. The greatest British weakness was the defencelessness of the East Coast harbours, if regular troops were out of the country. If the Germans tried a full-scale invasion rather than a raid, they would use the whole High Seas Fleet in support. In that case the British fleet would have to cruise much further south, accepting much greater exposure to torpedo attack – hence requiring a much stronger screen against it.
The manoeuvres killed the idea that destroyer groups searching at night could find the enemy fleet to attack it. There were almost no such attacks, because no one knew where to send the destroyers – it was difficult enough for the picket line to find the enemy fleet in the first place. Both of the C-in-Cs in the exercise kept their destroyers with their battleships to use in the expected fleet action. Presumably both felt that they would be at a considerable disadvantage without these craft. ‘As we have strong reasons to believe that this is the German plan, no doubt a British C-in-C would do the same in war … would always wish to have at least one flotilla with him – hence at least two flotillas must be attached to the Battle Fleet.’ Results were limited because systematic training of destroyers to work with the battle fleet had only recently begun. Given their limited endurance, destroyers had to be based on the coast, to which they could return to fuel without losing too much time before reaching the fleet cruising offshore. All the likely bases – Harwich, Immingham, the River Tyne, Rosyth, Aberdeen, Invergordon and Scapa Flow – were undefended.
In October 1913, fleet commander Admiral Sir George Callaghan issued a short memorandum summarising lessons of the manoeuvres. The object was to destroy the enemy fleet by gunfire aided by torpedoes. To make gunfire effective, each battleship had to be able to concentrate on its target in the enemy battle line, without being concerned with attacks by other enemy ships. To this end, the roles of other classes of warships were defined mainly in terms of beating off attacks by other types of enemy warships. Destroyers were the exception. Their primary role was to attack the enemy battlefleet with torpedoes. Their secondary role was defence against enemy torpedo craft, although the two might be reversed in some circumstances.
In the wake of the manoeuvres a conference was held at Cromarty in October 1913, and new plans were drafted. They were sent to Home Fleet commander Admiral Callaghan in May 1914. Upon the outbreak of war he was to take his fleet towards the enemy coast in a ‘reconnaissance in force’ before returning to his assigned war station. He would repeat such sweeps at intervals (over different ground each time) to demonstrate to the Germans how hazardous it would be for them to send a raiding expedition or other relatively weak fleet detachment across the North Sea towards the British coast. The fleet should cruise in such a way that its precise position was screened effectively by flotillas and cruisers spread ahead of it over a broad front – which might well intercept any German ships en route to ‘execute some special mission’. The idea was that German uncertainty as to the position of the British fleet might be an effective deterrent. However, in June 1914, the War Staff also wanted both Callaghan and his designated successor, Jellicoe, to develop a range of detailed plans. They included both the fleet sweep (Plan M) and a close blockade of the German Bight by strongly supported flotillas for four or five days to close the Elbe (Plan L.a without any local base, and Plan L.b with a base seized from the Germans), as well as a plan to establish a cruiser-destroyer base near Stavanger, Norway to control the exits from the Skaw (ie, from the Baltic: Plan T). Callaghan’s flag secretary, Roger Backhouse, complained in a memo that the war planners gave the fleet far too many disparate objectives (including covering the expeditionary force).
Destroyers working with the fleet on the projected sweeps needed considerably greater endurance. The War Staff was responsible for framing detailed war plans – implicitly, for making sure that ship designs matched the requirements those plans implied. In about October 1913, the War Staff suggested that the big leaders, rather than the much smaller conventional destroyers, should be the standard for the future. Their main advantage, compared to the destroyers, was considerably greater endurance. There was interest in a new long-endurance fleet torpedo cruiser (the ‘new Polyphemus’) and also in a fleet submarine, as alternative torpedo platforms to conventional destroyers. The cruiser did not materialise at least in part because the outbreak of war the following August precluded introduction of radically new designs. This policy review seems to have been the origin of an idea that British fleet building policy should turn away from expensive capital ships and towards the torpedo as a dominant arm. The new policy was never evident because the 1914–15 Programme was overtaken by the outbreak of the First World War. In retrospect, given the limited performance of surface-launched torpedoes during the First World War, the British were probably lucky that this particular revolution in naval thinking did not quite come to pass.
Callaghan’s view of the destroyer as fleet torpedo boat won out to the extent that the 1914–15 design was rethought as, in effect, a seagoing torpedo boat with an extra (fifth) tube and with two 12-pounders instead of three 4in guns. The DNO objected strongly, but this did not affect the outcome. The new torpedo-heavy destroyer would have been built had not the First World War intervened. When he became fleet commander in 1914, Admiral Jellicoe agreed that cruisers were much better destroyer-killers than destroyers, but he felt that he had too few of them. He therefore saw his destroyers more as defensive than as offensive. However, he seems to have looked forward to a time when he could use his destroyers more offensively.
One lasting lesson of Admiral May’s exercises was that, at least in daylight, destroyers should fire maximum range browning shots rather than shorter-range shots intended to hit any one specific target. Night attacks would be a different proposition. May had envisaged 3000-yard shots, but there was no reason not to use the full potential of the heater torpedo. British interest in such browning shots was probably unique among the navies of the time.41 Too few torpedoes were carried to afford wasting them, so ‘browning’ did not mean attacks at extreme range, or at columns of ships not presenting good targets, ‘nor does the expression mean that less care may be taken in accuracy of aim at the selected ship of the line, or in accuracy of director setting so far as this is practicable’. If target ships were in close order (600-foot ships 2½cables – 500 yards – apart), destroyers could hope for 40 per cent hits, based on how much of the target space the ships occupied. The safe margin of range was given as 20–30 per cent of running range, which would mean firing a 10,000-yard torpedo at 7000–8000 yards (a memorandum on employing destroyers in a fleet action gave examples of director settings and errors for ranges up to 8000 yards). This was a recent idea: ‘further experience at peace practices should throw more light on this point’. Opportunities for such shots were likely to come suddenly and to be fleeting, so flotillas had to be ready to seize them. Fleet commander Callaghan later pointed out that single-target attacks (maximum range 3000 yards) were pointless against ships still capable of shooting back.
A new destroyer manual drafted in 1913 reflected the new tactical ideas. Destroyers were primarily an offensive arm of the fleet, to be used in combination with the fleet’s guns. Independent attacks, day or night, were pointless because hunting groups probably would never find their targets. At night, moreover, targets could manoeuvre freely. However, during a day gunnery action, battleships would have to follow a more or less steady course in order to control their fire effectively. Destroyers could fire ‘browning shots’ at groups of ships from outside the ranges at which they would be vulnerable to enemy fire. This was much what May had argued two years earlier, but at longer range. British destroyers would work around to attack position, approaching at twenty to thirty degrees off the enemy’s beam, then turning two points so as to bring their tubes into firing position (they could fire only from more or less on the broadside). Approaching at too fine an angle, the ships would have to turn onto a collision course to fire. Speed would matter, and destroyers would be unable to achieve it in a head sea.
The fleet’s destroyers would stay in touch with the enemy after the day action, closing in to attack at short range (browning shots would be pointless against targets free to manoeuvre and not tightly grouped). That is what the British destroyers did after Jutland.
It was not clear how effectively British destroyers could protect against the likely threat of German torpedo attack – the Germans never failed to take their destroyers to sea, and used them in all fleet exercises.42
In a March 1914 memorandum on the use of destroyers in a fleet engagement, fleet commander Admiral Sir George Callaghan envisaged a flotilla on either flank of his fleet as it approached the enemy, each slightly back from the columns of battleships. Once the fleet deployed, one flotilla would steam at the head and one at the tail of the British line. Ideally destroyers would attack from the van. British tacticians dismissed the German pass-through tactic except under the most favourable conditions of weather and gunnery range (and superiority of German gunfire) because they assumed the Germans still had short-range torpedoes; they would have to spend too much time under fire before attacking. However, once the Germans had British-style long-range torpedoes aboard their destroyers, the situation would change radically, their ships firing almost as soon as they emerged from behind their battleships, achieving valuable tactical surprise.43 It was thought that only the latest German destroyers had 7500-yard torpedoes; most had 5500-yard weapons. Hence ‘at present’ most German torpedo craft would have to close to short range.
One point not made in any of the pre-1914 tactical discussions was the possibility that the threat of destroyer torpedo attacks could be used to force manoeuvres on the target fleet. That was evident at Jutland, both in attacks by Beatty’s destroyers to break up the German battle cruiser line, and in the German attack to cover the fleet’s withdrawal.
When he took over the Grand Fleet, Admiral Jellicoe accepted that cruisers were far better than destroyers as a defence against German destroyers. He felt he had far too few cruisers, and he feared that Germany would pick its moment when it could take its entire large torpedo fleet to sea (whereas a quarter of Jellicoe’s ships might be fuelling or refitting). He therefore reversed Callaghan’s order of priorities. Even so, he envisaged ‘browning’ attacks once the gun action began.44
By mid-1914, formal instructions had been drafted to create a destroyer screen against submarines. As suitable weapons did not yet exist, this was acknowledged as more a look-out than a screen, but the same instructions foresaw a true screen using the modified sweep described below. As the most numerous fast surface combatants, destroyers were the natural ships to be considered as anti-submarine platforms. It happened that serious development of ASW weapons for British destroyers coincided roughly with the movement of destroyers back into the battle fleet, so it is impossible to say that the new threat helped justify that integration. It is, however, striking that before any development of special weapons (or even trials), the French submarine programme was used to help justify destroyer construction about 1901.
The earliest exercises to evaluate the submarine threat were proposed by the Home Fleet commander on 29 December 1903 and conducted between 8 and 18 March 1904. The main conclusion was that the mere presence of submarines could make the area off a port (where the fleet might expect to conduct a blockade) entirely untenable, ships having to maintain high speed to avoid being torpedoed.45 After a February 1904 discussion, a few simple weapons were produced: a hand charge, a towing charge, an indicator net, and a lassoo net. Submarines would show themselves only when they showed their periscopes, so the periscopes would become the aim points. Thus the towing charge was fitted with a grapnel intended to foul the submarine’s periscope, and to be set off by a firing key on board the destroyer armed with it. The umpires pointed out that the trials would have been even more depressing had they been less artificial. For example, the destroyers often presented themselves as tempting targets, because they had to stop to use their grapnels. They were often within 400 yards of a submarine, proceeding dead slow or stopped.
The modified sweep was the first destroyer anti-submarine weapon issued in numbers to Royal Navy destroyers. It was conceived as a means of screening a fleet, the destroyers trailing the sweep steaming ahead of the fleet athwart the area in which a submarine would have to wait to attack them. Because the sweep was streamed directly abaft a destroyer, a single ship could not easily use it. In October 1914, for example, Commodore (S) Roger Keyes pointed out that a submarine would evade a single destroyer, and would not be deterred; only dense screens would be effective. One idea mooted at this time was for destroyers to screen decoys which submarines might try to penetrate the screen to attack. The decoy role was clearly dangerous, but it seemed that the surviving torpedo gunboats had such shallow draught that they might be immune to torpedo attack (however, they also had poor sea-keeping qualities). Complexity made the sweep difficult to stream and to recover, and it could not survive for long when streamed. In February 1916, the modified sweep was ordered removed from all Grand Fleet destroyers and stored at bases so that it could be used to screen disabled ships and the like. The modified sweep was succeeded by explosive (Type Q) paravanes.
(DRAWING BY A D BAKER III)
Among the suggested antidotes arising from the manoeuvres was an explosive sweep proposed by a Captain Ogilvy in a 9 June 1905 report: an explosive charge in a depth-keeping kite. In theory, it would foul any submarine it encountered, exploding on contact. That might mean destroying a periscope or, in later formulations, destroying the submarine herself. The sweep was first tested, on board a flotilla of torpedo boats trying to counter a submarine in a channel, in January 1906.46 Sweeps (such as contemporary mine sweeps) were suspended between pairs of boats, so that three boats could cover a front of about 150 yards (a pair could sweep a width of 100–150 yards). Thus seven boats (three, with a pair and another threesome in echelon abaft them) could sweep a 500-yard path. The strain on the sweep equipment was such that speed was limited to six knots. Initially charges were fired electrically, but Vernon pointed out that they could also be fired on contact.
Further submarine exercises, including working with a battle fleet, were conducted in June and July 1909, and in March 1910 a Submarine Committee was formed to investigate means of countering enemy submarines. It included British submariners, who could give a realistic idea of the strengths and weaknesses of their craft. The Committee called for trials with the proposed high-speed sweep using either a Tribal class or a River class destroyer, as well as trials to determine if a destroyer could torpedo a submarine at 500 yards range when her periscope was spotted (a test soon showed that was unlikely). It was also suggested that observers in a balloon or dirigible might see submerged submarines, much as seabirds spotted fish prey from aloft.47
The Commodore (S), the head of the submarine service, pointed out that to be effective a sweep force had to cover a broad front (in effect, the limiting lines of approach). The faster the force, the narrower the front: a fifteen-knot ship facing a six-knot submarine would need protection over three-quarters of a mile. Moreover, ships protected in this way might find it difficult to manoeuvre freely to dodge torpedoes. Even so, two torpedo gunboats (Speedwell and Seagull) conducted trials. Their sweep consisted of two two-inch wires, one thirty feet above the other, kept in position by large kites, the two towing ships being 2½ cables (500 yards) apart. A lighter arrangement was proposed for destroyers. Kite trials began in May 1910, the two gunboats running at up to fourteen knots. The Tribal class destroyers Maori and Crusader were ready by mid-November 1910 with strengthened decks and special winches. They towed their sweeps at up to seventeen knots. An explosive charge would be run down the sweep wire when it snagged a submarine. The submarine Al was fitted so that it could submerge automatically. On one run, she passed over the sweep; in others she simply parted it. It seemed unlikely that there would ever be enough time for a charge to run down the wire to the submarine.
Simply tying two ships together by the stern was a disadvantage, so an alternative single sweep, carrying a charge below the surface, was quickly developed, and used by HMS Crusader against A1 in July 1911, with gratifying results. It carried a towed charge (as proposed by the Committee in March 1911), which would be drawn down the wire if the sweep fouled a submarine. On trials, HMS Crusader tried to manoeuvre a charge near the anchored (surfaced) submarine Holland 2. A 72lb charge fired remotely when directly below the target (on the last of four trials) badly damaged it. On 27 October 1911, approval was given to fit towing charges to two destroyers in each of the four fleet flotillas, as well as to both a destroyer and a torpedo boat attached to HMS Vernon.48 The Anti-Submarine Committee suggested ‘a screen of fast vessels with towing charges ahead of the Fleet’. Submarines would either evade this screen or attack it. To attack, the submarines would have to show their periscopes and thus give the destroyers targets. A submarine evading the screen (not showing the periscope) would be effectively blinded at a critical time, risking being rammed if she came up too close to the bow of a ship. Submarines approaching from ahead would find it difficult to estimate the speed of the fleet, but would be unable to attack without doing so. Outlying pickets could deter submarines from approaching from the flanks by even if they lacked towing charges. The screen would be stationed three to four miles ahead of the fleet, its number depending on fleet speed.49
Further experiments showed that periscopes might not be spotted. The first sign of a submarine might be the explosion of her torpedo. Any submarine in the swept path had to be attacked, whether seen or not. A modified single sweep tested by HMS Seagull in June 1912 had upper and lower wires, the latter carrying nine 80lb charges, so that instead of being dangerous (to the submarine) only at one end, the sweep could damage a submarine wherever it was fouled. It also covered a much larger area than the Single Sweep: a vertical area 300 yards long and forty-eight feet deep (and a submarine would have to dive to seventy feet to clear the lower wire). The ends of the wires were arranged so that a signal was generated whenever either was fouled, the signal being needed to cause an operator on the towing vessel to trigger the charges, HMS Maori was used for further trials. After the C-in-C Home Fleet had been consulted, it was decided in July 1913 to fit the modified sweep for trials in four light cruisers, six mine-sweeping former torpedo gunboats, and two destroyers. The Commodore (S) considered the modified sweep an ‘unpleasant menace to a Submarine approaching at an angle to the course of the vessel towing [it], and it is superior to anything which has been suggested in that its operation does not depend on the Submarine being sighted’.50
While the Admiralty awaited trials of the modified sweep, all the single sweeps were placed on board destroyers of the 4th Flotilla.
Tests with shells fired at a submarine periscope showed that they tended to ricochet rather than dive towards the submarine, but there was still some hope that heavier (6in) shells would bury themselves slightly and so have a better chance of transmitting a useful shock when they exploded. However, interest in non-ricochet shells (for ranges to 2000 yards) and in charges which could be projected from a 12-pounder gun (to 500 yards range) remained.
None of this solved the problem of the submarine’s basic invisibility. In a December 1911 report, the Committee mentioned the failure of attempts at electric or magnetic detection. There seems to have been no prewar interest in using underwater sound, even though underwater sound communication was well known. British work on hydrophones began by November 1914.
On 5 May 1914, the Submarine Committee laid out a series of ASW measures. Patrol flotillas of destroyers would be fitted with the modified sweep on a priority basis, to screen the fleet when it approached or left its bases, the most likely places it would be attacked. As more sweeps were produced, they would be installed aboard the fleet’s destroyers. Other ASW measures explored at this time included the use of submarines lurking off an enemy’s bases (or cued by patrolling aircraft in British coastal areas), and scouring areas with fast motor craft to force submarines to dive and thus to use up their reserves of battery power. The Committee considered the danger zones to be within sixty miles of the enemy’s coast and within one hundred miles of the British coast, at places such as approaches to bases and to coaling ports. The open sea would be far safer.
On the eve of war, on 6 July 1914, the Committee reported that the destroyers Goshawk and Lizard had both been fitted with the modified sweep, and that they had operated it at speeds between six knots and twenty knots. The sweeps were considered so important that, a few days after the outbreak of war, a Commander Superintending Modified Sweep (CSMS) was appointed. His staff gradually grew, and on 8 December 1914 it became the Submarine Attack Committee (SAC), which survived (albeit renamed) until the formation of the Anti-Submarine Division in the Admiralty in December 1915.
At the outbreak of war, arrangements were made to fit the modified sweep to destroyers at Chatham and to trawlers at Lowestoft, and to provide fifty sets of equipment at each of Portsmouth, Devonport and Chatham. The modified sweep enjoyed its first, and perhaps only, success on 4 March 1915, when HMS Viking spotted U 8. The submarine dived, and the destroyer was unable to hit her with her sweep. Later, HMS Maori spotted the periscope, and HMS Ghurka caught an obstruction in her sweep five hours after the first sighting. The charge was fired, and U 8 surfaced and surrendered.
Given the urgency of the submarine problem, existing single sweeps were retained in service after the outbreak of the First World War while modified sweeps were being fitted. They were still in service in mid-1915. In August, Admiral Jellicoe asked the captains of the 2nd and 4th Destroyer Flotillas for maximum towing speeds, for how long the sweeps could be towed continuously, for how well they kept their depths, and for how long they could remain efficient while towed. He wanted to know whether destroyers screening capital ships sent to sea for gunnery practice on 2 August had used their sweeps. Destroyers had not towed their sweeps while screening, or when they had to operate at high speed, because maximum towing speeds were sixteen knots for the modified sweep and fourteen knots for the single sweep. Sweeps were towed continuously for no more than two or three hours at a time. Both sweeps reduced destroyer speed by about one knot. The CO of the 4th Destroyer Flotilla reported that above fifteen knots the modified sweep tended to fail because its wire chafed through in three or four hours. The single sweep, which was inherently less useful, could survive at speeds of up to twenty knots. HMS Shark reported that the complicated modified sweep once fouled badly when some of the charges passed through the bight at the inboard end of the float wire (it was impossible to know that this was happening). On another occasion, the charge wire carried away where it passed the wire lizard on the kite wire from which the float wire towed, HMS Garland reported that a sixteen-point turn twisted the float wire and charge wire around each other in a hopeless mess, the firing circuit being stranded and parted in several places, so that it became useless. Destroyers using sweeps would have slow to ten knots to get the sweep in or out, and they would desert the heavy ships for about an hour before dark simply to haul in and coil down the sweeps. The sweep fouled the after 4in gun, it presented an explosion hazard, the kite and sweep could easily be swept overboard to foul propellers, and it required too many personnel.
Moreover, the careful calculations made prewar, showing that a submarine would have to penetrate a destroyer screen of modified sweeps, seemed less and less realistic. The same calculations which made destroyer ‘browning shots’ attractive also applied to submarines, which could fire from outside a screen. The sweep would be effective only against a submarine trying to manoeuvre diagonally through a screen, which some critics considered unlikely. It should be limited to hunting submarines in narrow channels or in harbour approaches. In October 1915, the Captain (D) of the 2nd Destroyer Flotilla (on board HMS Active) commented that the modified sweep cannot be used to protect a fleet at the speeds now necessary’ (the fleet at fifteen knots, the destroyers at seventeen knots so that they could manoeuvre relative to the fleet). In October, Admiral Jellicoe asked to land all modified sweeps aboard Grand Fleet destroyers, and to stop fitting them to new destroyers. His preferred alternative was a combination of explosive paravanes and depth charges. The Admiralty ordered the modified sweep retained in destroyers not attached to either the Grand Fleet or the Harwich Force; in addition, Grand Fleet destroyers of the 2nd Destroyer Flotilla, which already had the modified sweep, should retain it. In other Grand Fleet destroyers the modified sweep would be replaced by two Type D depth charges and the stern sweep (the explosive paravane described in a later chapter). Only on 5 January 1917 did the 1st Destroyer Flotilla report, however, that it had landed its modified sweeps, and that it was leaving the Firth of Forth.
The massive use of mines by both the Japanese and the Russians during the Russo-Japanese War impressed all observers. With limited resources, the Japanese used their destroyers as both minelayers and minesweepers, but it was generally accepted that more specialised ships would have been better.
During the Russo-Japanese War Japanese destroyers dropped mines in the path of the Russian fleet, causing it to veer off. That widely reported incident led major navies to think about destroyer-laid, mainly drifting, mines. The new DNO, who was interested in such experiments, was Captain John Jellicoe. In 1906, Admiral Beresford wrote that his fleet had shown that a destroyer could drop existing mines, but she had not yet taken the next step and gone to sea with them aboard. A 1909 report described Japanese destroyer minelaying; the Japanese were surprised that, although drifting mines might be illegal, they had not been adopted by the Royal Navy.51 The Japanese considered this kind of attack ‘second to none’. Ships would pass 1000 to 2000 metres ahead of the enemy, on his course, dropping mines. This work ‘… was the most dangerous of all… dangerous alike to friend and foe. After dropping the mines, the TBD or TB would steam away out of it as fast as possible. As there was no way of knowing where the mines were after they were dropped, the Japanese officers say that any attempt at rescue work would be suicidal ...Very often in place of the real mines dummies were thrown overboard in the track of the Russian fleet. Straw bags were generally used and on many occasions, once particularly outside Port Arthur the Russians were thrown into confusion by them and turned back.’
For the Royal Navy, there was little point in considering such tactical mining until destroyers were reintegrated with the battle fleet. In autumn 1912, the Controller asked the DNO and the DNC to submit a joint report on this idea, and the DOD and the Chief of Staff (COS) recommended arming destroyers with a drifting mine powerful enough to damage a battleship seriously. The initial proposal was to arm 30 per cent of destroyers with fifteen mines each. The Assistant Director Torpedoes wanted the mines also to be capable of being moored. The DNO and the DNC pointed out that a destroyer could not carry a mine powerful enough (250lb charge) to put a first-class armoured ship out of action. The maximum for a mine without sinker would be 600lbs (31in diameter). Total weight of mine, sinker, and mooring would be 1200lbs. Each destroyer should carry six mines. On 24 April 1913, the First Sea Lord ruled that all destroyers of River and later classes should carry four mines each on the upper deck (each with 120lbs of TNT), the mines normally to be drifting but suitable for mooring if need be. Little came of this idea, although L class destroyers apparently carried mine rails until 1915.
