Type A class (Shimushu class) costal defense ships - Redefining a classification

Would you like to see the Type A / Shimushu class costal defense ships added to war thunder?
  • Yes, I think they would be worth adding
  • Maybe
  • Unsure
  • I don’t think we need this class in-game

0 voters

What refits of the Type A class would you like to see added to the game?
  • Type A class As built (All)
  • Type A class 1942 refit
  • Type A class 1943 refit
  • Type A class 1944 refit
  • Unsure
  • I said no to the first question

0 voters

Type A class (Shimushu class) costal defense ships - Redefining a classification

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(Type A class vessel, IJN Shimushu, 1940)


Background & History

The Type A class coastal defense ships or kaibōkan were a class of vessel built during the second world war, the original versions were built actually just prior to the Japanese joining the war in the late 1930’s and early 1940’s. It should be noted that their are 2 Type A class costal defense classes, the original Type A or Shimushu class, and the modified Type A class or Etorofu class, the main difference is that the class construction was simpler in the design and construction but beyond that were more or less the same design. Despite the first ships being built in the late 1930’s the origins of the design go back all the way to the first London naval treaty but by the point these ships were being built the Japanese had withdrawn from the Naval treaty system yet their design was still heavily influenced by the treaties, especially since they were the reason they were built in the first place. With the major naval treaties of the interwar period Japan like the other nations took steps in some shape or form to get around restrictions set by major naval treaties and during which Japan like other signatories made attempts to get around some of these restrictions. With the London naval treaty the maximum total tonnage allowance dedicated to destroyers as well as the restrictions on destroyer designs had been defined by the treaty which like the rest of the ship types already limited had put a cap on the amount of destroyers the Japanese could built with the allowance given leaving the Japanese at a disadvantage to the US and UK who were permitted to have a larger numbers of destroyers, as a result the Japanese would try once again to exploit a loophole and in terms of getting around the destroyer limitations in 3 different forms, however it must be stated that the one the Type A design was meant to exploit really wasn’t a exploit but rather legally permitted by the treaty. The 3 ways the Japanese tried to get around the limitations for destroyers was to try a build a ship with half of the armament of a Fubuki class destroyer on a hull which displaced so little that it would be exempted from being considered a destroyer which would mean they could build as many as they wanted which resulted in the Chidori class, the other line which the Type A class used was part of Article 8 of the treaty which permitted the construction of ships between 600 to 2,000 tons of displacement which had no more than 4 guns of a caliber as large as 6 inches which and was larger than 3 inches in caliber, carrying no torpedoes, and were no more capable of higher than 20 knots to be built in unrestricted amounts creating a weird sort of loophole within the treaty without blatantly needing to be creative and this made these ships completely treaty compliant, the third loophole which really was not getting around it but was the simplest exploit the Japanese used was lying about the displacement of what was suppose to be treaty destroyers.

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(Type A class vessel, IJN Hachijo, 1941)

The way this design “exploited” the treaty system was clear for all to see and in turn other nations built similar ships following this same defined line for such a ship. The Type A class would only be ordered after the Japanese withdrawal of the naval treaty systems, this was due to the Japanese having a low priority for such vessels which meant that they were only ordered in 1937, the contracting for designing the ships was given out to private firms which was awarded to Mitsubishi Heavy Industries, the idea was that the design would be simple for construction which could fill the roles of defending various assets closer to home which would involve protection of territory close to home, minesweeping, and convoy escort which would then allow the Japanese to dedicate their destroyers to higher priority roles and missions, their design themselves and the concept behind them is also the reason why they are by the West referred to as escort vessels as they had a similar role, concept, and capability to US destroyer escorts and British frigates and corvettes however the Japanese classification for these ships was kaibōkan which was for coastal defense ships, however this classification by the Japanese had been redefined by this class on how it was used, previously it was used to define older more obsolete vessels such as old sloops and battleships, this also had a unusual result, when it comes to Imperial Japanese navy warships, ships which are either a cruiser or larger have a chrysanthemum emblem placed at the front of the bow however this was not done for smaller ships such as destroyers and anything smaller, but the Type A class was the weird exception since the kaibōkan classification was given to them and was used only previous as stated on outdated sloops and battleships, so initially they were considered as warships of sorts however due to their smaller size was disregarded by other ships, in one case this lead to one case when the commanding officer of a destroyer signaled the Kunashiri that they failed to salute the destroyer, with the commanding officer of the Kunashiri apologizing by signaling that they salute you (the destroyer) and the commanding officer coming over in one of the ships boats to personally apologize to the destroyer’s commanding officer. Due to these complications the crest on these ships were all removed by 1942, this is why in some illustrations and models of Type A class vessels the chrysanthemum emblem is placed on the bow as they were one of the most unusual cases of a Japanese naval vessel which had the chrysanthemum emblem not due to how they were but the of their classification due to how past ships of their classification used them which was in another way in which the Type A class redefined the kaibōkan classification. Originally the Type A class was suppose to consist of 16 ships, however Mitsubishi design with the ship made them a little too well designed of sorts though in terms of the context of what they were asked for they did a bad job as the design itself proved to be more complicated than was desired as they had a double curve bow and forecastle deck, reinforcing to the hull and improving insulation so that they would be able to handle the more rough and colder environment of the northern seas around the Kurile Islands as they were designed, this meant that while they were able to perform their design role they were too complicated in fact to mass produce as the Japanese wanted to which caused the remaining 12 ship to be canceled in favor of a improved design which was known as the modified Type A class.

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(Type A class vessel, IJN Shimushu, 1942)

The modified design took basically the preexisting ship however they were build more simply as they were build with a simpler stern, bow, and bridge design which they hoped would ease the construction process of the ships, another thing was that unlike the Type A class the modified variant would include less portholes and the amount varied by individual ships, however it still was not enough though the new design was ordered for a total of 30 ships, but due to the design complications this saw multiple classes come forth which meant that only 14 of the ships would be competed to the design of the modified Type A class the rest of the ships were modified in their design which allowed for them to be built to a newer and more capable design as the Japanese realized they need more escort type ships which were also more capable which saw ships competed to the designs of the Mikura, Hiburi or Ukura classes or the Type B and the improved Type B class kaibōkan. The funny thing about the bringing forth these new classes lead to much confusion for the shipyards building these as their class plan names were originally Type A, Type B, and modified Type B but their class name were all the Shimushu class which in 1944 saw the Japanese change it to where all the ships plan name was Type A however they were now grouped into separate classes of the Shimushu class which was made up of the Shimushu and Etorofu class, the Mikura class which consisted of the Mikura and Hiburi class, and the Ukura class which just was made up of the Ukura class, though the subsequent type C and D class never changed as they called originally No.1 and No.2 class respectively. During the second world war the Shimushu class would actually sustain minimal losses as they only had 1 ship sunk however the other 3 would have different fates as one was wrecked, another scrapped, and another given to the Soviet Union post war. During the class would act in their original roles which meant that they were never in direct confrontations with allied surface vessels, instead they were often assigned to roles such as convoy escort as well as patrols.

In terms of main armament of 3 12 cm/45 (4.7") 3rd Year Type naval guns in single mounts equipped with gun shields, the AA armament was at first just 4 25mm Type 96 AA guns however over the war more guns would be installed, the ships also carried depth charge throwers though the Type A had 2 however the number was later increased to 6. During the war itself the class would receive extensive refits which saw more and more guns installed however they were able to retain the full main armament, the ships would see the amount of AA gun reach as high as 15 25mm guns in 5 triple mounts, they would also received a anti submarine mortar though this was not like the hedgehog, this was a literal mortar which had previously been used by the Imperial Japanese army, and beyond this they would receive new radar and sonar among other things.


Specifications

Displacement:

860 tons standard

1,020 tons fully loaded

Length: 77.7 m (255 ft) o/a

Beam: 9.1 m (29 ft 10 in)

Draft: 3.05 m (10 ft)

Speed: 19.7 knots (22.7 mph; 36.5 km/h)

Complement: 150

Sensors and processing systems:

Type A class 1942 refit

1 x Type 93 sonar

Type A class 1943 refit

1 x Type 22 radar

1 x Type 93 sonar

Type A class 1944 refit

1 x Type 13 radar

1 x Type 22 radar

1 x Type 93 sonar

Armament:

Type A class As built (All)

Main armament:

3 x 12 cm/45 (4.7") 3rd Year Type guns (3 x 1)

AA armament:

4 x 25mm/60 Type 96 AA guns (2 x 2)

Other armament:

2 x depth charge throwers (12 - 18 depth charges total)

Type A class 1942 refit

Main armament:

3 x 12 cm/45 (4.7") 3rd Year Type guns (3 x 1)

AA armament:

4 x 25mm/60 Type 96 AA guns (2 x 2)

Other armament:

2 x depth charge throwers (36 depth charges total)

Type A class 1943 refit

Main armament:

3 x 12 cm/45 (4.7") 3rd Year Type guns (3 x 1)

AA armament:

15 x 25mm/60 Type 96 AA guns (5 x 3)

Other armament:

1 x 81mm Type 97 ASW mortar

6 x depth charge throwers (60 depth charges total)


Sources

Spoiler

Shimushu-class escort ship - Wikipedia

https://ja.wikipedia.org/wiki/占守型海防艦

"A" escorts (SHIMUSHU) (1940 - 1941)

Japan - Kaibokans. - Shipbucket

Japanese Escorts

Image sources

Spoiler

Japanese Escorts

Category:Shimushu-class escort ships - Wikimedia Commons

2 Likes

I hope we see more coastal defense ships added. +1

I think that if it’s to have any value in the game it needs to come in the 1943 refit and we would need to have aiming reticles for mortar and throwers (suggestion). Without that it’s not much better than Chidori, a ship that is absolutely horrible to play.

But with the refit… I can see it being a next unlock in the coastal tech tree after the Chidori herself.

+1, would love to see some more of the lesser known vessels in the game like these!