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We are discussing the destroyers of the Royal Navy in the early part of World War Two, and we are asking why the early war built RN destroyers were so lightly armed. So, we must clarify; to what are we comparing them?If we compare them with the one-off Japanese destroyer Shimakaze, we must admit that the RN ships’ torpedo battery comes up short; the ten 21-inch torpedo tubes of a J/K/N-class ship compares poorly with the Shimakaze’s fifteen 24-inch tubes, along with the much superior performance of the heavyweight Japanese weapon. A Tribal-class’ four tubes pales in comparison. Yet, the performance shortfall was something which all navies’ torpedoes demonstrated next to the Japanese ‘Long Lance’, because 21-inch was, by the 1920s, very much the international standard. Furthermore, Shimakaze was never repeated, nor her heavy torpedo battery; most ‘special type’ destroyers had eight or nine, with the late-war Akizuki class possessing only four tubes.Now let’s compare the British ships to something else.The Allen M Sumner class destroyers, another late-war design, were designed for ten torpedo tubes and six main guns… exactly the same numbers as for a J/K/N, built up to five years earlier.Do you know what I think? I think this question is really about the British ‘interwar standard’ fleet destroyers of the 1930s. These ships each carried four single 4.7-inch main guns and eight torpedo tubes in two quadruple mountings, except for the I class, which had ten. [1](Above: G-class destroyer HMS Grenade.)What are we now to compare them with? Shimakaze[2] again? Or a Sumner?[3] The Japanese vessel displaced an enormous 2,570 tons compared to the British ships’ meagre 1,370 standard, while even the more reasonably-sized American ships still displaced 2,200 tons standard. Size-wise, there was a huge difference and there should hardly be any surprise that the interwar British destroyers were somewhat more lightly armed than the two foreign examples.What was the design genesis of these modest British destroyers? They were derived from the experimental HMS Amazon[4] & Ambuscade[5] , two destroyers of less than 1,400 tons displacement, which were themselves developed from the successful and numerous V&W class fleet destroyers of late World War One vintage.[6](Above: Note the similarity between this V/W class destroyer and HMS Grenade)These 1,100-ton ships were the result of progressive development of destroyers during the war, from the pre-war 965-ton L class’[7]three centreline 4-inch guns and two twin torpedo tubes, to the Thornycroft Modified W class’ four superfiring 4.7-inch guns and two triple torpedo tubes. The V&Ws were well capable of matching or besting any predicted new German destroyers, giving the RN both a numerical and qualitative advantage. The only drawback to the design was the speed; where the L class had been able to steam at 29 knots, the mid-war R class had got up to a brisk 36. The only slightly increased size of the later V/Ws, coupled with their much heavier armament, resulted in a drop-off to 32 knots maximum, which the Admiralty considered acceptable as a war exigency.Come the interwar period and the RN once more wanted higher speed from its destroyer force, hence the competition which resulted in the 37-knot Amazon & Ambuscade. On the specified displacement, an increase in armament was impossible, but that did not matter in 1926. The huge USN Clemson class[8] destroyer programme had yielded ships with a broadside of just three 4-inch guns and six torpedoes - admittedly they carried twelve tubes, but these were mounted on opposing beams. No, armament on the British ships was already adequate, but would be further improved during the 1930s with more torpedoes. AA armament was modest, being either a 3-inch gun and a pair of pom-poms, or a pair of quad heavy machine-guns - very normal by international standards for the 1930s.Yet, by the time these 1,350-ton four-gun destroyers were being series-produced, other navies were starting to turn out even larger types, with more guns. Japan started the trend towards ‘super-destroyers’ with the Fubuki class of 1926,[9] carrying six 5-inch guns and nine heavyweight torpedo tubes. These ships were fast and impressive, but overly ambitious in their combination of armament and displacement; too much was attempted initially and the six-gun heavy destroyer was not really perfected until the Asashio class in 1937 (below).Other nations tried the heavy destroyer concept with varying degrees of success. Italy’s Navigatori class of 1928[10] were 1,900-ton 38-knotters, but for all their impressive size, they featured just six 4.7-inch guns in three twin mountings, giving them a fifty percent increase in broadside weight over the Amazon, with no advantage in chase fire or torpedo battery whatsoever. They were subject to rebuilds to improve their stability prior to WW2, losing their impressive speed advantage in the process. Still, they were equivalent in prestige and role to Britain’s Tribal class, suffering similar heavy losses from constant front-line service.(Above: Italian destroyer Nicolo Zeno.)French super-destroyers, or contre-torpilleurs, were much more impressive, with a series of ships carrying five 5.5-inch guns, making them almost the equal of a WW1 light cruiser in fiepower, yet much faster. These were the ships which could beat the Japanese specials in a gunfight! Yet their six or seven tube torpedo battery was still very moderate, given their 2,400-ton displacement, until the advent of the extraordinary le Fantasque class of 1933. These ships carried nine torpedo tubes, five heavy guns and could steam at an incredible 45 knots! All other destroyers in the world were inferior to these amazing warships (below).[11]It should be noted that this class did not kick-start a destroyer arms race. Rather, they ended it and began a new ‘scout cruiser race’ as Italy laid down the Capitani Romani and France the two-ship Mogador class, each with eight five-and-a-half inch calibre guns and very high speed. Comparing the RN’s pre-war destroyer force with them would be unrealistic.There was also a move by the British to curb this ‘minor warship’ arms race; the London Naval Conference of 1930. The resultant treaty (London Naval Treaty - Wikipedia) placed a limit on destroyer numbers and maximum individual tonnage; 1,850 tons per ship and guns no larger than 5.1-inch calibre. By the terms of the treaty, the le Fantasques were technically light cruisers.The Americans played ball, after their flirtation with the eight-gun super-destroyers of the Porter and Somers classes. The pre-war Benham and Sims[12] classes, which bore the brunt of much fighting in 1942, were of 1,400 to 1,500 tons standard, a little more than the British interwar standard, but could still only ship four guns and a broadside of eight torpedo tubes. Partly this was because of the adoption of the high-angle mounting for the main guns, but at least this did have the benefit of off-setting their very light secondary AA armament of four machine-guns. Overall, the USN destroyers prior to the Benson/Gleaves classes were little better than their pre-war RN equivalents.And the Porters?[13] They carried eight guns in four twin low-angle mountings, no use for air defence, because of inadequate weight margins. Their eight-tube torpedo armament was good, but for AA defence they relied on a pair of Chicago Pianos; very poor medium AA guns. In fact, the RN’s Tribal class[14] compared very well with them, having one bank of TTs less but carrying a much more effective quadruple 2-pounder anti-aircraft gun. And when it came time to address the air threat more seriously? The Porters which were modified usually came out of refit with just five main guns and half the number of torpedoes, while Tribals replaced ‘X’ twin 4.7-inch mounting with a twin 4-inch high-angle gun, leaving them still with eight guns for use in surface actions. Horses for courses.But I just know that many of you are screaming at me for not addressing the German threat. Ah yes, the German destroyers with their terribly powerful five-inch guns, compared to the feeble four-point-sevens of the British ships. Germany had gone for quality in a game where numbers were always against them, but the results were not all that impressive, I am sad to say.The original Z1 class[15] had five main guns, as did most German destroyers during WW2. These guns had a good rate of fire yet, with six- and eight-gun British destroyers emerging at the same time, they offered no advantage in firepower over their enemies. The smaller interwar standard ships were a little overwhelmed by them, yes, but that was to be expected. What was not expected was that the German ships would be consistently matched by the capabilities of the best British destroyers. Even the vaunted ‘Narvik class’ super-destroyers, with their four or five 5.9-inch guns had such a hopelessly slow rate of fire of 8rpm per gun that they also failed to deliver the killer advantage time and again. On a few occasions they proved themselves deadly warships, of course, but not super-weapons.So, were the early war British destroyers under-armed? Not especially, no. They were generally quite good enough. They were a match for any early war German destroyer, while even the pre-war British destroyers could match most Italian destroyers. The most exceptional foreign examples of the type were indeed bigger and more heavily armed, but they were far from being the universal standard in 1939. If anything was holding back British destroyers of World War Two from being superlative, it was the British desire to adhere to treaties and limit growth, while providing for the maximum number of hulls in this absolute workhorse of a warship type; and numbers would be so very important in the coming war.(Above: HMS Kelly. Ten torpedoes, a quad pom-pom, and 72 rounds fired per minute. Hardly under-armed.)Footnotes[1] I-class destroyer - Wikipedia[2] Japanese destroyer Shimakaze (1942) - Wikipedia[3] Allen M. Sumner-class destroyer - Wikipedia[4] HMS Amazon (D39) - Wikipedia[5] HMS Ambuscade (D38) - Wikipedia[6] V and W-class destroyer - Wikipedia[7] Laforey-class destroyer (1913) - Wikipedia[8] Clemson-class destroyer - Wikipedia[9] Fubuki-class destroyer - Wikipedia[10] Navigatori-class destroyer - Wikipedia[11] Le Fantasque-class destroyer - Wikipedia[12] Sims-class destroyer - Wikipedia[13] Porter-class destroyer - Wikipedia[14] Tribal-class destroyer (1936) - Wikipedia[15] German destroyer Z1 Leberecht Maass - Wikipedia