Selkiö Naval Treaty
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| Ten-Power Treaty | |
|---|---|
 Signing of the treaty | |
| Type | Arms control |
| Context | WSS |
| Signed | March 12, 1923 |
| Location | Selkiö, Rajamaa |
| Effective | September 27, 1923 |
| Expiration | 1936 |
| Negotiators |
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| Signatories |
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| Parties | |
The 1923 Selkiö Naval Treaty, also known as the Ten-Power Treaty, was a treaty signed by all major parties involved in the War of Serenoran Succession, as well as a few neutral states, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Selkiö Naval Conference, held in Selkiö, Rajamaa, from December 15, 1922 to March 12, 1923. The treaty was signed by the governments of Fȳrēþel, Menghe, Sieuxerr, Dayashina, Tír Glas, Rajamaa, New Tyran, Akeniran, Serenoro, and Ostland. It predominantly limited the construction of battleships, battlecruisers, and aircraft carriers by the signatories. Other categories of warships, including cruisers, destroyers, and submarines, were not limited in quantity by the treaty, although a qualitative limit of 12,000 tons displacement was in place for the latter vessel types.
The treaty was concluded on March 12, 1923, with ratifications being exchanged in Selkiö on September 27, 1923.
Later conferences sought additional limitations of warship building, specifically for cruisers. The push for limiting cruiser proliferation was primarily brought about by escalating tensions at the end of the 1920s, and the terms for the Selkiö Naval Treaty were modified by the Avallone Amendment of 1930. However, by the mid-1930s, Dayashina and Serenoro had openly renounced the treaties, which in turn spurred other signatories to hurriedly abandon the treaty restrictions; This effectively left any further naval arms limitation impossible post 1936.
Background
In the aftermath of the War of Serenoran Succession, Dayashina and Tír Glas possessed the some of the worlds most powerful navies, having been largely unmolested by the events taking place in Casaterra and Vinya, which had seen Casaterran naval dominance shaken to its core. While coalition forces of Sieuxerr, New Tyran, and Serenoro had succeeded in the Casaterran campaign, the Vinyan campaign had ended with defeat; The inability of the Casaterran powers to effectively land enough war materiel, had cost both the coalition and Fyr Navy dearly. As such, in little more than 5 years, the balance of power had shifted drastically, leaving few options on the table for the war-exhausted Casaterran colonial powers.
Vying for control over the Helian Ocean, the Dayan and Glasic navies had embarked on a struggle of constant one-upmanship, the gravity of which was outlined by the launching of Nemain on April 6, 1920, with its 18" main armament; While the Dayan navy thereafter launched Miyuki and Shirayuki, Mikazuki and Kikuzuki, Taiho and Shoho, in the following 3 years as a response in attempt to underline its supremacy. In the same period the Glasic navy had managed to launch or lay down 4 further battleships, though even with Nemain the gap would need to be closed, and so plans called as far for another battlecruiser before the Selkiö Naval Conference was held. With the prospect of the Dayan-Glaso naval arms race continuing on its already hyperbolic path, the bolstered rising challenger of the Fyr Navy, and the stirring of the Soodean Navy, the world look set to descend into an arms race that Casaterran nations could ill afford.
Negotiations
1923 Terms
| Country | Capital ships | Aircraft carriers |
|---|---|---|
| Dayashina | 453,000 tons | 160,000 tons |
| Tír Glas | 453,000 tons | 160,000 tons |
| Rajamaa | 394,000 tons | 160,000 tons |
| New Tyran | 383,000 tons | 160,000 tons |
| Ostland | 324,000 tons | 120,000 tons |
| Fȳrēþel | 324,000 tons | 120,000 tons |
| Serenoro | 324,000 tons | 120,000 tons |
| Menghe | 289,000 tons | 80,000 tons |
| Sieuxerr | 232,000 tons | 80,000 tons |
| Akeniran | 105,000 tons | 0 tons |
The treaty set stringent controls on the total tonnage and construction of capital ships and aircraft carriers, as well as restrictions on the size of vessels. The tonnage limits defined by the articles of the treaty, those stipulating total tonnage, gave a strength ratio of approximately 6:6:5.5:5.5:4.5:4.5:4.5:4:3:1 for the nations; Dayashina, Tír Glas, Rajamaa, New Tyran, Ostland, Fȳrēþel, Serenoro, Menghe, Sieuxerr, and Akeniran, respectively.
The qualitative limits outlined for each vessel type are as follows:
- Capital ships, battleships and battlecruisers, were limited to 35,000 tons standard displacement and guns of no larger than 14-inch calibre; Except those vessels prescribed on a quantitative per nation basis, which may displace upto 46,000 tons and possess guns of no larger than 16.5-inches in calibre.
- Aircraft carriers were limited to 40,000 tons displacement and heavy guns of no larger than 8-inch calibre, of which not more than 10 may be carried. Each signatory may also not commission any vessel of the type until 1925.
- Cruisers were limited to 12,000 tons displacement and guns of no larger than 8-inch calibre.
- Coastal defence ships were limited to 8,000 tons displacement and capability to make no more than 18 knots speed.
- Monitors were limited to 8,000 tons displacement and capability to make no more than 10 knots speed, and possessing not more than 2 guns greater than 5-inches in calibre.
The treaty also detailed by article # the individual ships to be retained by each navy, including the allowance for Tír Glas to retain the Nemain which exceeded the treaty restrictions via 18-inch main armament; The ship was given special consideration, and resulted in an exception made for its use.
Article # detailed what was required to render a ship legally ineffective for military operation. In addition to sinking or scrapping, each signatory nation was permitted to retain; One vessel completely stripped of all armament, but retaining its armour, propulsion, and steering, for the purposes of target evaluation; Along with one other vessel disarmed by diminution of the main armament to 6 barrels or less for all armament over 8-inch in calibre, for the purposes of training.
Article # specified the vessels of each nation to be scrapped to comply with the treaty, and when the remaining ships could be replaced.
Definitions
The treaty outlined in detail the binding definitions for each vessel type, including those not strictly limited by the treaty. The definitions allowed for the quantitatively free construction of cruisers, coastal defence ships, and monitors, while keeping qualitative limits on such types of vessel.
The definitions outlined in the treaty are as follows:
- Capital ship; A capital ship, in the case of ships built hereafter, is defined as a vessel of war, neither an aircaft carrier, nor coastal defence ship, nor monitor, whose displacement exceeds 12,000 tons standard displacement, or which carries any armament exceeding 8-inch in calibre.
- Aircraft carrier; An aircraft carrier is defined as a vessel of war with a displacement in excess of 12,000 tons standard displacement designed for the specific and exclusive purpose of carrying aircraft. It must be so constructed that aircraft can be launched therefrom and landed thereon, and not designed or constructed for carrying a more powerful armament than that allowed to it under Article # or Article # as the case may be.
- Cruiser; A cruiser, in the case of ships built hereafter, is defined as a vessel of war, neither coastal defence ship, nor monitor, with a displacement in excess of 2,000 tons but not exceeding 12,000 tons standard displacement, and which carries no armament exceeding 8-inch in calibre.
- Coastal defence ship; A coastal defence ship, in the case of ships built hereafter, is defined as a vessel of war, not a cruiser, with a displacement in excess of 2,000 tons but not exceeding 8,000 tons standard displacement, and which possesses the capability to make not more than 18 knots, and carries any armament exceeding 6-inch in calibre.
- Monitor; A monitor, in the case of ships built hereafter, is defined as a vessel of war, neither cruiser, nor coastal defence ship, whose displacement does not exceed 8,000 tons standard displacement, and which possesses the capability to make not more than 10 knots, and which carries not more than 2 guns of any armament exceeding 5-inch in calibre.
- Standard displacement; The standard displacement of a ship is the displacement of the ship complete, fully manned, engined, and equipped ready for sea, including all armament and ammunition, equipment, outfit provisions and fresh water for crew, miscellaneous stores and implements of every description that are intended to be carried in war, but without fuel or reserve feed water on board.
The word "ton" in the present Treaty, except in the expression "metric tons", shall be understood to mean the ton of 2,240 pounds (1,016 kilos).
Vessels now completed shall retain their present ratings of displacement tonnage in accordance with their national system of measurement. However, a Power expressing displacement in metric tons shall be considered for the application of the present Treaty as owning only the equivalent displacement in tons of 2,240 pounds.
A vessel completed hereafter shall be rated at its displacement tonnage when in the standard condition defined herein.
Effects
The Selkiö Naval Treaty effectively halted the long period of ever increasing capital ship displacement, which had been the prominent characteristic of naval development across Septentrion, as naval designers constantly sought ways of gaining an advantage over opponents. Many of the ships which were currently under construction prior to the treaty, were either scrapped or converted into aircraft carriers, and many pre-existing ships which did not fall under the treaty, were either converted into training ships, or sunk as targets. Largely the initial treaty limits were respected, and would be extended under the Avallone Amendment of 1930, which sought to add quantitative limits to vessel types already outlined with qualitative limits on the treaty. It would not be until the mid-1930s that navies began once again to build battleships of ever increasing size, at which point the trends of the past naval arms race would emerge once more; This was due to the governments of Dayashina and Serenoro, denouncing the treaty in its entirety on June 21, 1934 and February 10, 1936 respectively.
Avallone amendment
Although the treaty set restrictions on the qualitative nature of cruisers, coastal defence ships, and monitors, it did not set any quantitative limits on the vessel types; This meant that any signatory nation was legally permitted to build as many of the types as they liked.