A large naval escort vessel, capable of a variety of tasks including independent cruises for the purpose of power projection. The original concept was introduced near the end of the 19th century, when battle fleets were still at the heart of most nation's navies. With the advent of the steam turbine, small, fast torpedo boats represented a grave threat to the capital ships. The Japanese used them with telling effect against the Russian fleets at Port Arthur and at Tsushima. What was required to counter this threat, was a vessel capable of matching the speed of the torpedo boats, and sinking them with superior firepower. The "torpedo boat destroyer" was born.
Early versions of this class of warship - prompted by an impressive demonstration of the steam turbine by HMS Turbinia - gradually increased in displacement from 150tons to 350tons by the start of World War I. By now, of course, the tasks allotted to the destroyers had expanded beyond the simple screening of fleet anchorages against torpedo boat attack. The destroyers had become flotilla leaders of light forces, and were employed off the enemy coast as scouting and hunting units. In time, they supplanted the torpedo boats as hit-and-run raiders within the Royal Navy.
A further, unwelcome development was the need for escorts to the huge merchant convoys. The fleet destroyers (by now displacing around 2000 tons, and desperately scarce) could not be spared for convoy escorts. A separate class of small, lightly-armed escort destroyers of around 1100 tons displacement, were built for the purpose. Optimised for anti-submarine work, they were the forerunners of the modern frigate - mass-produced and designed around ASDIC (later SONAR) and depth-charges.
The RN, of course, was not alone among the world's navies in building and developing destroyers. Those of other navies tended to be larger vessels, much closer in size and general philosophy to the light cruisers of the RN. Indeed, the large "Narvik" class vessels of the German Kreigsmarine were comparable in firepower (if not quite in reliability) to the British "Dido" class.
The US Navy saw the destroyer as an all-rounder, and developed it as such, with one eye on the Japanese in the Pacific region:
As with the Japanese designs, however, the attempt to arm these ships adequately led to dangerous topweight issues. Not until the 2100 ton Allen M. Sumner class did the Americans produce a genuinely first-rate destroyer.
USS De Haven
From then onwards, of course, US designs were always going to be bigger. Today's benchmark class, the Arleigh Burke at 8000 tons, is nearer to a cruiser than a destroyer in size.
The USN disagree: they classify a cruiser as a dedicated "area air defence" warship, whereas the destroyer is a general-purpose escort.
Russian naval planners, on the other hand, stayed much closer to the original "torpedo boat destroyer" concept. (See above notes for Port Arthur and Tsushima.) Operating in limited waters, the Tsarist (and later Soviet) fleet did not possess a true blue-water capability until long after WWII had ended. For this reason, they had no requirement for the hard-hitting all-rounder the destroyer became elsewhere. It was only at the insistence of Admiral Sergei Gorshkov that the Soviet navy became a deep-water fleet during the Cold War. By this time, anti-submarine warfare was the main focus for the Red fleet, and all of its escorts were described as either "Small", "Medium" or "Large" anti-submarine vessels. The current Russian fleet reflects this approach: its Krivak and Udaloy classes lack many of the capabilities of similar sized vessels in Western navies.
As the RN adjusted to the Cold War, destroyers grew ever bigger and more complex. The battlefleet passed into history; the light cruisers soon followed. The last true all-gun destroyers in the Fleet, the 2800-ton Daring class, mounted 6 x 4.5" guns, and the Australian Darings (HMAS Vampire and Vendetta) were rated by US naval commanders as light cruisers when employed on the gun-line off Vietnam. A third RAN Daring, Voyager, was lost in 1964 when she collided with the aircraft carrier HMAS Melbourne during an exercise.
This tragedy, which resulted in enormous loss of life when Voyager was cut in half as she crossed too close to the carrier's bows, highlighted the dangers of the destroyer's primary task at this time: screening of carrier task forces. Over 80 men died, all on board Voyager.
THE MISSILE AGE
In the late 1950s, improvements in propulsion and radar guidance systems made the shipborne guided missile a reality. These would fall into three main categories: Long-range anti-aircraft missiles, for protection of a task force from air attack; Short-range anti-air missiles, to provide individual ships with defence against low-level air attack; and Surface-to-Surface Missiles (SSM) for use against other ships.
The RN's first operational Surface-to-Air Missile (SAM), SeaSlug, came into service in 1962 aboard the largest destroyers the RN had ever owned.
Study the above photo of the County-class destroyer HMS Norfolk. On the fantail are twin launchers for the SeaSlug SAM; a Wessex helicopter sits abaft the hangar; abeam of the hangar are the two quad SeaCat launchers for close-in anti-air defence; in B position sit four MM38 Exocet SSMs; in A position she carries a Mk 6 mounting with twin 4.5" DP guns. As can be seen from this array of armament, the County class vessels, at 5200 tons standard displacement, were really light cruisers ... but the distinction by now was becoming moot. The new Type 12 frigates being built at that time, were of a similar size to the Darings and were becoming much more of a general-purpose warship.
However, fleet air defence had by now been identified by the RN as the destroyer's main role, with the frigate - as in WWII - specialising in ASW (Anti-Submarine Warfare). This arrangement was to continue with the next generation of large destroyers, the Bristol (Type 82) - slightly larger than the Counties, and mounting the new SeaDart SAM:
HMS Bristol - 1973
As the new carriers these ships were meant to escort were cancelled, only Bristol herself was completed.
A QUART INTO A PINT POT
The successor to the Counties and Bristol was the Type 42 (Sheffield class).
HMS Birmingham - Second Type 42 to be completed after HMS Sheffield
The design was basically an attempt to get SeaDart and a helicopter to sea on the smallest possible hull. At 3500 tons standard, the T42 was just over half the size of the Bristol. At the time of the Falklands War in 1982, the RN deployed a class of frigate (the Broadsword, or Type 22) which was slightly larger than the T42 at 4000 tons.
The rationale behind the scaled-down design of Sheffield and her sisters, was simply that in order to build sufficient hulls (14) to deploy a viable fleet of AAW escorts, those hulls had to be affordable. Everything was trimmed to the bone: Only 22 missiles, a manually-operated loading hoist, one anchor, one helicopter, and - a fatal cut for Sheffield in the Falklands - only one fire-main. When, on 4 May 1982, an Argentine Exocet struck her amidships, the impact destroyed this vital piece of damage-control machinery, and fires could not be brought under control. She burned out - with the loss of 22 lives - and was later towed out to sea and scuttled.
Despite the limitations of the class, T42s performed well in the South Atlantic, providing Naval Gunfire Support (NGS), and shooting down a respectable tally of enemy aircraft with SeaDart. As most AAW engagements took place in the enclosed waters of Falkland Sound and San Carlos Water (the landing point for most of the Task Force troops), the long-range, high-altitude SeaDart had difficulty in acquiring targets against the radar "clutter" of land and sea. Ironically, the supposedly ASW-oriented frigates of the Broadsword class achieved greater success with their superb SeaWolf short-range SAMs.
The venerable T42s (in their final Batch 3 configuration) have at last retired. And though it might seem to be "back to the future" in terms of ship displacement, the RN have completed their planned commissioning of six of these.
The Daring class (Type 45) are the last word in AAW destroyers to date. Salvaged from the wreckage of two attempts at international cooperation in warship design, they represent the British input into a Pan-European joint venture which eventually equipped the French and Italian navies with the Horizon frigate. The British went their own way, and the Type 45 is the result.
At over 8000 tons full load, they are large warships - although their exceptionally clean lines are deceptive. Large bridge windows, a lack of on-deck equipment (ship's boats, mooring bollards etc.) and the elimination of right-angles in the hull and superstructure, all reinforce the impression of a much more compact warship than the Counties or Bristol.
Questions have been raised regarding the interoperability of these ships with allied units. The Spanish navy built their F-100 class AAW frigates around US equipment (they were nicknamed "Baby Burkes" for their Arleigh Burke derivation). The RAN have built three AAW destroyers based on the F-100, for the same reasons of close cooperation with the Americans. The major difference between the US, Spanish and Australian vessels and the Darings, is the sensor system. The AB-based ships all operate the US AEGIS combat system, based on the powerful SPY-1A "billboard" style radar. T45 operates the PAAMS (Principal Anti-Air Missile System), a mix of Aster-15 (short-range) and/or Aster-30 (long-range) missiles - christened "Sea Viper" in RN service - with two powerful, versatile radars: Sampson and S1850M, as its eyes and ears.
Some awesome claims have been made about the power and flexibility of Sampson. It certainly has longer range than SPY-1A, even if only by virtue of being mounted higher above the waterline. But the major attribute of the system, is its ability to multi-task. This means that a Sampson-equipped warship can track and engage multiple threats simultaneously, whether incoming missiles or aircraft in any attack configuration. The nasty surprises of the Falklands War should not be an issue for the Darings.
The Daring Class pioneered a revolutionary form of propulsion: IFEP (Integrated Full Electrical Propulsion). It's complicated, involving an intricate relationship between a pair of WR21s - very powerful 21MW Gas Turbine engines - and two much less potent 2MW diesel generators. The system has developed a nasty habit of shutting down under certain conditions, leaving the vessel totally without power. This appears to have happened a lot in hot and humid environments, such as the Arabian Gulf - a notorious Black Spot for Gas Turbine operation. A fix is underway, involving installation of more powerful diesel generators. The issue became problematical through the necessity for extended tours in the Gulf region. Original planning was for 12 hulls; successive reviews saw this reduced to 6 - putting extra demands on the ships which were built.