…With the onset of the Depression the impetus for greater naval limitations which had failed after Geneva returned. The fiscally conservative President Curtis was one of the first leaders to realize the full implications of the Depression and invited the parties of the London Naval Treaty to the United States to work out new limitations and deal with various brewing issues. Wilmington Delaware was chosen as the site of the conference, as Washington DC itself was thought too hot and muggy during the summer when the Conference would take place.
At the suggestion of the British the Dutch and Germans were invited, mostly due to the British desire to halt further construction of their Panzerschiffs…
…The most politically fraught issue of the conference was to determine who would be added to their ranks. There was no objection to bringing the Dutch in at the same level as Spain. There was however considerable objection from France at the prospect of bringing in Germany. The French saw that admitting Germany into the naval treaty system essentially meant eliminating the naval limitation clauses of the Versailles Treaty. And if the naval clauses of the Versailles Treaty were eliminated, then other clauses might be. Not willing to risk a slippery slope leading to a strong German army once more threatening France the French refused to allow this. Given that altering the Versailles Treaty required the consent of all the Big Four, the result was the exclusion of Germany…
…The biggest issue leftover from the LNT was limiting cruiser tonnage below the First Class. The United States wanted to build a limited number of 10,000 ton 6” cruisers to supplement their large 8” cruisers. Britain wanted to build large numbers of under 8000 ton cruisers with 6” or possibly smaller guns. The United States had no interest in building such cruisers nor interest in building enough larger cruisers to provide Britain the aggregate tonnage that she wanted. This dichotomy had sunk the Geneva Naval Conference.
At Wilmington however the Americans were willing enough to compromise. The Depression had hit hard and extensive spending was on the horizon. The oldest capital ships in the American battle line were nearing replacement age. Japan had finished ordering her 8” cruisers allotment and was starting a series of 10,000 ton 6” cruisers that could spark a costly race if unrestricted. There was an ongoing competition in Destroyer construction, with Japan having effectively upended the board with the Akatsuki class and actually managing to outbuild the US in destroyers, mostly as Congress saw the mass of WWI era flush decker types as a sufficiency of destroyers. If avoiding these meant having to accept a bunch of cruiser tonnage the US would not actually build, that was the price of saving money.
The US proposed as the 6” cruiser limits for the chief powers 250,000 tons, matching the limits on the A class cruisers established in the LNT. Britain proposed a 200,000 ton B class of 7501-10,000 ton ships and 150,000 ton C class of 7500 tons and under with a wrinkle. Namely that Britain, would be able to trade A class and B class cruiser tonnage for C class at ratios of 2 for 3 and 3 for 4 respectively. This would allow Britain the ability to retain the existing cruisers of the RN and commonwealth Navies and build 30 more vessels of around 6,000 tons, or a 7:23 mix of 7500 and 5500 ton vessels, to fill their requirements.
The US was nervous about the prospects of anything less than complete equality. However they were willing to agree to it, if they got something in return. Namely that the British would agree to their proposal about extending the Capital Ship building holiday for the three principal powers, the US being well aware the French and Italians would never agree if it applied to them. This was something the British were very leery about given how hard used their remaining 13.5” ships were. However they had just gotten the Americans to agree on a proposal that gave them enough cruiser tonnage for their needs, and a superiority in total cruiser tonnage they could use to proclaim the continued paramount status of the RN. In what was probably the biggest British mistake of the conference they agreed to the American proposal for extending the Capital Ship building holiday until 1936.
As a result the cruiser limits for the United States were 250,000, 200,000 and 150,000 tons. For Britain 205,000, 80,000 and 380,000 tons. For Japan they were 175,000, 140,000 and 105,000. For France and Italy they were 100,000, and 140,000 tons of combined 6” cruiser tonnage. For Spain and the Netherlands it was 37,500 and 52,500 tons of combined 6” cruiser tonnage below 10,000 tons, the smaller powers being allowed to do so to avoid having to build ships too large for their needs…
…Following cruisers was the matter of destroyers. While individually cheap, ton for ton they were the most expensive surface vessels and if not limited could prove costly. The US proposed a tonnage limitation of 200,000, 200,000, 140,000. 80,000, 80,000, 30,000 and 30,000 tons. This was enough to let the US keep their 20 “Destroyer Leaders” built or building, as well as 160 of the 237 remaining Flush Deck destroyers. Destroyers would be limited to 2,000 tons and 130mm/5.1” guns, with the few ex-German war prizes with 150mm guns grandfathered in. This limit allowed most of the extant destroyers to qualify, save the French Super Destroyers and largest Italian Esploratori, which would go under their cruiser tonnage, which both parties could afford.
At British insistence a rule was made than only 20% of Destroyer tonnage could exceed 1500 tons, in order to allow them to build enough to be sufficient and avoid having to replace too many vessels. This was accepted and a 16 year replacement rule was put into place for post LNT Destroyers, with 12 years for pre LNT destroyers…
…Aside from surface vessels submarines also had to be regulated. Namely the fact that construction of large submarines was beginning to be a significant budgetary issue. France was building a 3500 ton sub with a pair of 8” guns, intended to be the first of a class, Britain had a 2800 ton design with 4 5.2” guns, Japan was building a class of 2200 long endurance vessels, and the US had 27 large submarines of between 2100 and 3200 tons built or building in 9 different classes. Continuing to build subs like this was now too expensive.
Of course the issue was how to limit the submarine. It was decided that 2,000 tons would be an upper limit for new submarines, existing submarines larger than that could be retained, but no new vessels larger than that could be built. This was at US insistence so that they could keep the large submarines they intended to fight Japan with. Furthermore no new submarine could carry a gun larger than 5.1”, nor could an existing submarine be refitted with such a gun. Replacement time would be 13 years
Tonnage limitations ended up defined by US and French minimums. The US wanted 100,000 tons to keep its existing large subs and gradually replace the S boats from WWI. France, having been forced by circumstances to abandon its 90,000 ton goal, still wanted 75,000 tons. Thus the ratios had to be modified. The US and UK would receive 100,000 tons, Japan, France and Italy 75,000 tons, and 25,000 tons for the Spanish and Dutch…
…One thorny question was the matter of light carriers. The United States had Bunker Hill, France Bleriot and Japan Hosho and Eisho, Britain having reconverted Egeria and Cavendish back to cruisers after determining they were of minimal value as carriers. These ships had been built under the assumption that there was no treaty, or that ships under 10,000 tons were not counted. Now that cruisers under 10,000 tons were counted they could no longer be cruisers and avoid being counted under aircraft carriers. Britain and Italy were all for counting them, Britain and France preferred to count them as carriers, best befitting the treaty, while Italy preferred cruisers to deny France one more cruiser. The United States and Japan however preferred they did not count. Doing so would deny them considerable tonnage that would make subsequent carriers they would build smaller.
Instead the US and Japan proposed that they be loopholed in. Of course both parties were well aware that doing so would require some horse trading, so they agreed that certain vessels would not count under any category, such as the large colonial Avisos of France and Italy. A list was made of armed vessels that would be excused from counting under any treaty category, which just so happened to include the three light carriers in question…
…In order to avoid arguments about minor classes of vessels it was decided that surface vessels of under 600 tons would not be counted. The United States had suggested 750 tons, but Spain commented that such was sufficient for a warship for Mediterranean operations and would not deter the French and Italians. It was further decided that ships of 600-2000 tons, that carried 4 or fewer guns above 3.1”, lacked provision for torpedoes and were capable of 20 knots or less would be unregulated, in order for all the powers to construct gunboats and patrol craft for colonial duty as they saw fit and avoid arguments there…
…The United States Navy saw no real way to build an effective cruiser for their needs on 7500 tons. Even with the improved alloys and machinery available to them the situation remained much the same it had been at the London Naval Treaty, with weight saving measures being offset by new sources of weight being found. They could build a cruiser with the speed, range, seakeeping and main armament to be useful, at the cost of inadequate armor and air defense. Fixing those meant compromising elsewhere, which meant something else was deficient. However the USN saw that they could build a very nice destroyer on 3,000 tons and that doing so was a way to get ahead of the Japanese.
The Japanese had invested heavily in 3500 and 5500 ton cruisers in the late teens and early twenties, ships of minimal combat value that were taking up their C class tonnage and could not be replaced until the late thirties and early forties. By contrast the United States, by dint of Congress not paying for any cruisers between 1905 and 1916, had no such vessels. If Congress would pay for them they could have 40 or 50 super destroyers built before then.
These would not be like the ships built by the French and Italians. Rather than trying to cram every possible knot of speed into the hull, the United States would settle for a mere 36 or 37 knots instead of trying to go above forty. Instead the ships would be much more seaworthy and far longer ranged, with a powerful DP armament of 8 5” guns rather than a fewer number of heavier anti-surface guns. The question of course was how many “Scout Cruisers” congress would pay for…
…Japan saw one important loophole in the treaty. Namely that vessels below 600 tons were unregulated. This was under the assumption that building a vessel both speedy, seaworthy and possessing both a gun and torpedo armament of note on that tonnage was impossible. The Japanese did not believe that it was. Their view was that based on a combat area off the Philippines they could build such vessels that could operate with the Combined Fleet. This would give them a leg up over the Americans, who having to operate from across the Pacific could not make use of such in concert with their Battle Fleet. Such vessels at most could be part of the Asiatic fleet, which would be dealt with in isolation before the Battle fleet was able to move.
The IJN wanted 20 of the vessels built as soon as possible. The Finance Ministry disagreed but rather than get into a fight about it they proposed a compromise. The Finance Ministry would fund several prototypes now, and if they still wanted those ships after seeing the performance of the prototypes the funds would be found for 20 of them.
The IJN agreed and four prototypes were proposed with varying combinations of propulsion machinery, armament and hull design, but all trying to fit half the firepower of an Akatsuki class destroyer on a third the displacement…
…Along with the Prototype torpedo boats the Japanese funded a “Special Type Gunboat”. A 20 knot, 2000 ton vessel, it had two twin 13cm DP guns and extensive accommodation for landing detachments. Accommodations that were located so that a second or third machinery plant could be fitted Aft, increasing speed to 27 or 31 knots, and that a third turret could be fitted fore, with torpedo flats replacing additional boat handling equipment amidships…
…Britain’s problem with the Treaty quickly became apparent. That their eight 13.5” armed battleships and two battlecruisers were hard used was well known. However the poor state they were kept in was not, and when they were inspected after the treaty their truly deplorable condition was discovered. Maintenance of the reserve fleet had been skimped on, given the ten year rule it was expected that the ships would be replaced before a conflict hence no need to put any money into them.
The WNT changed this. Now Britain had to keep those ships until at least 1936. Of them Tiger was in decent shape, as she had went into reserve only in 1929, but was the most worn out. The Iron Dukes were in poor but manageable shape, however the Princess Royal and older battleships were sufficiently degraded that returning them to service would require a functional rebuild. This left Britain with a major problem when the naval race of the late 30’s kicked off…
…Despite the Depression and the WNT both the French and Italians persisted with their plans for new battleships. Quite simply both of their battle fleets were of limited value and there was concern that their battleships were vulnerable to 8” shells from modern heavy cruisers at long range given their lack of deck armor. This could be fixed given rebuilds, but such rebuilds would still leave their ships inferior to even the oldest battleships of Britain, Japan and the United States, and behind the newest vessels of Russia and Spain.
Thus even with tight financial situations both navies were able to successfully argue that new battleships were needed in the early 30’s. Both came up with very similar plans, 4 light battleships of just over 30,000 tons which would be followed by 4 45,000 ton battleships when the financial situation improved, thus using up their allotted 315,000 tons. The 30,000 ton ships would be able to face the oldest capital ships of the dominant powers, be much superior to the existing vessels and be cheap enough for the strained environment of the 30’s.
The difference between the ships was due to the design philosophy in question. The French ships were an enlarged version of the Spanish Castila class using a new design of 330mm guns while the Italian ships had 9 343mm guns in three triple turrets, two fore, one aft and one of the fore superfiring over the other. Both were capable of over 30 knots of speed and were reasonably protected against their own armaments. The French design was better armored, but its two forward quads left it vulnerable to losing all its armament and gave it a blind spot aft. The Italian design was slightly bigger than the French design and was less vulnerable to such a catastrophic kill.
Of course both sides plans would change shortly after they were announced…
-Excerpt from Naval History Between the Wars, Harper & Brothers, New York, 2007
