1936 (cont)
In January, the Air Ministry had organised a series of trials between various calibres of aircraft weapons, basically .303, .5 and 20mm cannon. These tests showed the .303 calibre would be an inadequate weapon for future air combat, and that the .5 calibre wasnt much better (and weighed more). The best solution was the 20mm cannon. The results of these tests were passed on to the Navy.
At the end of January the government announced an expansion of the shadow factory program. The navy was promised that some of this effort would be allocated to them.
The international situation was getting worse with increasing speed during the year.
On the 7th March Hitler denounced the Rhineland provisions in the Treaty of Versailles and the Locarno treaty, and German troops marched in to occupy the Rhineland. This was seen, in the navy at least, as a sign that Germany would only be increasing its naval and anti-shipping capability in the near future, and that the proposed fleet levels and makeup would need to be accelerated. Unfortunately while the government agreed that there was a need for more defence spending, the Treasury was still insisting that this had to be moderate and not disrupt normal commerce. While the Admiralty did make the point that at the present moment the shipyards were still not fully utilised, there were bottleneck (both current and approaching) in a number of areas such as guns, armour and FC systems which would limit the number of hulls that could be sensibly laid down. While there were plans in place to improve this situation, it wasn't going to change overnight.
In addition, the main area of concern to the government was air defence - while it was appreciated that the naval threat was growing, the Royal Navy was still the most powerful in the world. The navy realised that this priority wasn't going to change overnight, but that it would be possible to get some improvements that were connected to the worries about air attack. A Shadow Factory system was being set up for the RAF, and it was pointed out that this would not only be important for the navy, but that in extremis navy planes would also be available to defend British airspace. Secondly, that improvements in the fleets light AA equipment, which they had been looking at for some time, could be developed partly with the (official) aim of improving land based defences. The governmant had already promised a portion of the effort would be forthe navy, but the Admiralty retained certain suspicions of the RAF.
In May the Air Ministry issued specifications for new cannon armed aircraft. Demonstrations of the Hispano 404 cannon had convinced them that this was currently the best gun available. The Navy (who had been invited to the demonstrations as observers) were in agreement, and it was agreed that the 20mm would be developed to fit both RAF and FAA planes. Since this would be an identical fit in RAF and FAA aircraft, the Air Ministry was given full control of the project.
Studies had been ongoing for some time of the problem of close defence. This was intended to stop torpedo bombers and dive bombers - the HA systems were seen as adequate against high level bombing, as it wasn't to shoot them down (although that was ideal), but to disrupt the attack so as to render it ineffective. However torpedo planes had far more opportunities to evade while attacking (and indeed the RN's own exercises had shown how effective they could be), and the speed of a dive bombing attack meant that the HA system just wasnt capable of stopping it.
These facts had been addressed some 10 years ago with the development of the multiple pom-pom system. However it was 10 years old (although thanks to the treasury there had been considerable delay in getting it into production), and as the latest trials and input from the FAA showed, it could use improvement. However resources were limited. There were also two foreign weapons available; the Swiss Oerlikon 20mm and the Swedish Bofors 40mm. The Bofors in particular was of interest as it was a much more modern system and had the range and stopping power the fleet needed. 20mm was seen as really too short ranged (although it was at least better than the 0.5" multiple machine guns) to be an ideal defence.
The report recommended 2 main actions. The first was the use of the 40mm bofors in single and double mountings for lighter ships or merchant ships, where heavy mounts and director control were inappropriate or unavailable. Because the gun used clips rather than a belt feed, they were much lighter (and without director control were felt not to need the long firing time of the belt-fed pop-pom). Since it was expected that these mounts would be used without a director, a heavy proportion of tracer was specified for them. It was noted that efforts needed to be made to speed up the manufacture of the guns in the UK, as the demand was seen to be high for both the land and sea based system. The navy would also consult with the army, who needed the single mounts for their own air defence.
The second action was to improve the 4 and 8 barrel pop-pom. Given the shortage of these, any improvements must cause minimal disruption to production for maximum benefit (refit would of course be ideal), and not add to the production time. Three main points were chosen for improvement. First, RPC was recommended for all 8 barrel, and if possible 4 barrel, systems. this would add weight, so new construction and larger ships would be the intended first recipients. Second was improvements in the belt feed, which was felt to be rather too fragile and temperamental. Any improvements or changes should be straightforward to retrofit. The third change was to the guns themselves and the ammunition. Tests seemed to show a considerable advantage to the Bofors over the pom-pom. The gun was longer, and the shells thus had a better range, improving the chances of shooting down at attacker. While the explosive charge was a little lighter, this wasn't thought important as a contact-fuzed 40mm would bring down any torpedo plane or dive bomber currently anticipated. It was therefore suggested that new and existing mounts should be modified to take replacement barrels as per the Bofors (this would be connected to the improvements in the belt feet mechanism), thus giving a notably better performance with the desired minimum changes. Finally some reports from the manufacturer and relevant engineering consultants indicated that the mechanics of the mount could be improved (and the mount itself lightened) by application of current manufacturing methods. Since this would entail changing the production line (which was not practical), it was recommended that some prototypes would be made, and all the improvements rolled into a new version for which new production would be set up (thus helping address the current shortage). The existing production line would then either be modified to produce the new mounts, or used to provide the older ones for air defence of land based targets (for which the deficiencies were not such an issue)
The treasury was not happy at the preference for the 40mm, as they pointed out that there were huge stocks of 2pdr shells available in storage. The navy didn't object on principle to using these, but considered that the value of ships mandated the best possible weapons for them, and that the older 2pdrs would be adequate for shore based defence.
As the treaty limitations were now relaxed, it was expected that at least Courageous and Glorious would be retained for some time (and one of the other carriers as a training carrier, at least for the next few years). It was pointed out that while this was very nice, the original assumption was that the new ships would be replacements, and therefore would use the escort vessels assigned to the older ships. If we were to be deploying more carriers, we needed more escorts.
There was an additional problem regarding the endurance of destroyers. An aircraft carrier had a large fuel load as it was expected that its normal operations would involve more (and higher speed) steaming. While escorting destroyers could refuel from their carrier, this took time and was not currently a well-practised procedure. So ideally destroyers designed to escort carriers should have a longer range. Secondly there was the issue of numbers. The ideal the Admiralty was now aiming for (though it didnt expect to get there before around 1944) was the 8+8 fleet and light carriers. Assuming a reasonable escort of 4 destroyers per carrier, this meant 8 flotillas of destroyers! While the staff appreciated that carriers were important, allocating them over a third of the current destroyer strength as escorts was certainly not possible. The solution was to assume that half the carriers (on average) would be with the fleet or fleet units, and hence would share their escorts (they would need a dedicated ship as plane guard) so 5 flotillas of destroyers would actually serve. This was thought possible to achieve in the 8 year period under discussion.
Te destroyer building program for this year was quite high, but current plans had only one flotilla of J/K class building over the next two years. It was therefore decided to build 2 additional flotillas, one each year, then take a closer look at the problem. Fortunately the treaty had also removed limits on 'light warships' under 3,000 tons. By now, the naval designers were heavily loaded; they were looking at a new generation of capital ships and cruisers, and there was not much effort available to design new destroyers. A compromise of a modified Tribal class destroyer was designed. One of the twin 4.7" guns was removed to save weight for a heavier close in AA suite (it was assumed a destroyer acting as a carriers guard would draw unwelcome attention from enemy planes. Four twin 4" guns was considered to give a better AA performance, but this was rejected due to concerns as to the suitability for low elevation fire, and the ability to protect the carrier from enemy light units was considered more important. Removing the 4.7's allowed the ships to carry an octuple pom-pom in its place, and 2 quads forward, making them very heavily protected. This was also to allow them to engage dive bombers (and, if rather suicidally, torpedo bombers) attacking the carrier. The navy was quite confident that the seamanship of its destroyer captains was up to the close manouvering required (even if some of the carrier captains were a little nervous at the idea). They would also, of course, be able to act as close in AA escorts for other ships, depending on the circumstances. While the general policy was to carry the armament on the ships, there were bound to be times when this ability to reinforce defences would be useful. The ships beam was widened, and the internal fuel tanks made somewhat larger (as a result of losing the 4.7" magazine); in addition the machinery was slightly modified to give better economy at the expense of a small loss of speed. The net result was a ship with 50% more range than a Tribal, at the expense of a couple of knots of speed. Given the high speed of the Tribal class, and the fact that the main purpose was escort, this was deemed acceptable, although it was noted that later ships should have more powerful machinery.
In June the situation in Europe took another turn for the worse, one which againt involved the navy. The Spanish Civil War broke out, and the Navy was tasked to undertake neutrality protection patrols. Both Hitler and Mussolini sent aid to Franco, and both the RAF and the FAA watched the introduction of modern types of German and Italian planes with interest.
In September, negotiations on licensing the Hispano cannon designs began. With prompting from the Navy (and an allocation of some funding to help), the Air Ministry gave funding to some British arms companies to test and evaluate the design in detail, and to start looking at what would be needed to change the specifications to Imperial measurements
After seeing the way in which Italy and Germany were cooperating in Spain, it came as no surprise that in late October an official Rome-Berlin Axis was announced. It did however worry the navy; up until now Italy had been seen, if not as an ally, then at least as a neutral. Now Italy moved to the status of a potential opponent, which meant more ships and resources had to be allocated to the Med. Despite the recent increases in spending on the navy, due to the time taken to build ships these resources would not be available for some years
