:: HISTORY OF THE SUBMARINE WEAPON (XII) ::

The submarine weapon in the interwar period (IV)

The large German transport submarines which operated in the eastern coast of United States during the First World War caused a great impression to the United States Navy, which back then was obsessed with its oceanic perspectives. In 1919 United States and Japan acquired the German U-cruiser project, which they used for the development of cruiser submarines endowed with a long operational range suitable for carrying out operations in the Pacific. At the beginning of the 1920s some designs were made, which were materialized as the minelayer submarine V4 (later renamed as Argonaut) and the cruiser submarines V5 (Narwhal) and V6 (Nautilus). All of them were very large vessels, being the two latter even larger than the French counterpart Surcouf. The V4 could carry 60 mines which were dropped through two portholes located astern. The V5 and the V6 had two torpedo tubes in the fore part of the huge engine room, instead of the mine storage.

The V4 introduced, as a novelty, a limited utilization of welding, which was expanded in the subsequent cruiser submarines, which comprised not only the Narwhal class (V5 and V6) but also the Dolphin class (V7) and the Cachalot class (V8 and V9). The two submarines of the Narwhal class could carry 39 torpedoes (stored inside the hull and also fastened to the weather deck) and they were armed with two 152-millimeter cannons, the largest ever installed in an American submarine. Unfortunately, these vessels were eventually regarded as too slow and vulnerable for taking part in patrols, but regardless of that, after having received new engines and four external torpedo tubes, they took part in the Second World War. The Nautilus had been also modified with facilities for refueling large seaplanes on the sea, but this feature was never used.

The subsequent Porpoise class introduced the fast and reliable Diesel injection engines which had been advocated by the United States Navy, and which gave a considerable advantage in respect of the projects from other countries. The submarines of the Porpoise class were smaller than the first American submarines of the interwar period but, in respect of those, they sacrificed very little regarding armament, operational range and other prestations. The small size of their engines contributed to a large extent to this. The submarines of the Porpoise class were classified into three groups; the first group comprised two vessels whose hull was based in that of the Cachalot class, the second group comprised two vessels whose hull was based in that of the Dolphin class and the third group comprised six vessels whose hull was as well based in that of the Dolphin class. During the Second World War the submarines of the Porpoise class underwent modifications in their conning towers and received two 12.7-millimeter antiaircraft machine guns. Some of them had two external torpedo tubes installed in the bow. The surviving vessels were left in the naval reserve after the war.

Regarding the more conventional attack submarines, the S class from the First World War was remarkable because in December 1941 there were still 37 of these vessels in service, albeit some of them were used only for training. Since these submarines had been designed for the defense of the United States territorial waters, in a time when Japan was an allied nation, their main defect relied in their short operational range, which prevented them from operating deep into the Pacific. The S class, designed by Holland, was accepted as a replacement for the previous O and R classes. The first 25 units were launched between 1918 and 1922. These units had a length of 67 meters and a displacement of 854 tonnes in surface. They were armed with four or five torpedo tubes and one 72-millimeter or 101-millimeter cannon.

The subsequent units, distributed among three groups of fifteen, six and four units respectively, introduced improvements. All of the units had a double hull as well as a similar armament and speed, but they differed regarding size and operational range. One of them carried a seaplane for a while and four of them were fitted with an additional torpedo tube astern. The largest part of the submarines of the S class deployed in the Far East were replaced by newer vessels in the late 1943, but some of them had some success; for example, the S38 sighted and reported Mikawa's fleet and the S44 topped her sinking tally with the sinking of the heavy cruiser Kako.

Production series of S-class submarines
Commission year Completed ships Remarks
Group I 1920-24 25 Namesake: S-1 class / Holland type
Numerals: S-1 and S-18 to S-41
Displacement: 854/1062 tonnes
Group II 1919-23 15 Namesake: S-3 class / Navy Yard type
Numerals: S-3 to S-17
Displacement: 876/1092 tonnes
Group III 1924-25 6 Namesake: S-42 class / 2nd Holland type
Numerals: S-42 to S-47
Displacement: 906/1126 tonnes
Group IV 1922 4 Namesake: S-48 class / 2nd Navy Yard type
Numerals: S-48 to S-51
Displacement: 903/1230 tonnes
S-2 1920 1 Prototype built by Lake Torpedo Boat
Displacement: 800/977 tonnes

American WW2 submarines
[1] The USS Nautilus as she appeared during the interwar period. The two units of the Narwhal class were regarded as being too slow for taking part in the war and, hence, they were used mainly in clandestine operations, albeit the USS Nautilus sank the damaged aircraft carrier Soryu after the Battle of Midway. [2] A submarine of the Gato class on the late 1942. In that time, the production neared three monthly units in three different shipyards and, due to the operational experience, the vessels had been fitted with smaller conning towers and surface weapons. [3] The S28 as she appeared in 1943. Designed by Holland, this submarine entered action along with her sister units at the beginning of the war, without a remarkable success. Whereas the largest part of the S-class submarines were replaced in 1943, the S28 was lost in 1944.

The first submarines operated by the Japanese Imperial Navy were British models designed by Holland and Vickers. Subsequent units were the No. 14 and No.15 designed by Schneider-Laubeuf, which were almost identical to another two submarines that the Schneider company had built for Greece. These were considerably larger units armed with six 450-millimeter torpedo tubes instead of only two. These units, which are referred as the S Type (Schneider Type), were the seed of the Japanese submarine program, which began to be developed only after the First World War. However, the No. 14 was never delivered to the Japanese, because in 1915 she was requisitioned by France and renamed as Armide.

The No. 15 was completed in 1917, at a time when Japan provided escort to convoys in the Mediterranean and also built ships for France, being eventually adscribed to the Japanese Imperial Navy as intended. She was fitted with a 76-millimeter cannon in 1919. A replacement for the No. 14 was built in the shipyards at Kure between 1918 and 1920. This vessel was slightly larger than the No. 15 and thus she was classified as an S 2 Type submarine. The No. 14 and the No. 15 were respectively renamed as Ha-9 and Ha-10 in 1924 and both were decommissioned in 1929.

The submarines of the S Type were followed by those of the Kaichu Type, which progressively introduced improvements through successive classes. The classes I, II and III, as the preceding units of the S Type, were armed with four 450-millimeter torpedo tubes and two external torpedo tubes, besides one 76-millimeter cannon; the subsequent classes were armed with four 533-millimeter torpedo tubes and one 76-millimeter or 120-millimeter cannon.

Kaichu I Kaichu IV
Length (meters): K I: 69.2
K II-III: 70.1 		K IV-V: 74.2
K VI: 73
Displacement in surface / immersion (tonnes): K I: 732 / 1016
K II: 752 / 1019
K III: 752 / 1013 		K IV: 762 / 1097
K V: 866 / 1047
K VI: 955 / 1219
Engine power Diesel / electric (HP): K I-II-III: 2 x 2900 / 2 x 1200 K IV: 2 x 2900 / 2 x 1200
K V: 2 x 1200 / 2 x 1200
K VI: 2 x 2900 / 2 x 1200
Speed in surface / immersion (knots): K I: 18.2 / 9.1
K II-III: 16.5 / 8.5 		K IV: 16 / 8.5
K V: 13 / 8.5
K VI: 19 / 8.25
Range in surface / immersion (nautical miles / knots): K I: 4000 at 10 / 85 at 4
K II-III: 6000 at 10 / 85 at 4 		K IV: 6000 at 10 / 85 at 4
K V: 9000 at 10 / 85 at 4
K VI: 8000 at 12 / 90 at 3.5
Fuel load (tonnes): K I-II-III: 75 K IV: 75
K V: 143
K VI: N/A
Cannons: K I-II-III: 1 x 76.2 mm K IV: 1 x 76.2 mm
K V: 1 x 120 mm + 1 x 6.5 mm
K VI: 1 x 76.2 mm + 1 x 13.2 mm
Torpedo tubes: K I-II-III: 4 x 45 cm (bow) + 2 external K IV-V-VI: 4 x 53.3 cm (bow)
Arms load: K I-II-III: 10 x torpedo K IV-V: 8 x torpedo
K VI: 10 x torpedo
Complement: K I-II: 43
K III: 46 		K IV: 46
K V: 44
K VI: 75

Kaichu I Kaichu II Kaichu III
Built in: Shipyards at Kure. Shipyards at Kure. Shipyards at Kure, Sasebo and Yokosuka.
Laid down: 1917 1918-1920 1919-1921
Launched: 1917 1919-1920 1919-1921
Completed: 1919 1920-1921 1920-1923
Decommissioned: 1932 1932-1933 1933-1936

Kaichu IV Kaichu V Kaichu VI
Built in: Shipyards at Sasebo and Yokosuka. Shipyards at Kobe. Shipyards at Kure and Kobe.
Laid down: 1921 1921-1924 1933-1934
Launched: 1921-1922 1922-1926 1934-1935
Completed: 1923-1924 1923-1927 1935-1937
Decommissioned: 1936-1940 1936-1945 -
Sunk: - - 1942-1943

After the end of the First World War the Japanese obtained the blueprints of the German cruiser submarines, which they used to develop successive classes of large submarines. Endowed with an extraordinary operational range, a notable displacement and an excellent artillery equipment, these vessels were perfectly suitable for effective operations in the whole area of the Pacific. Several of the cruiser submarines launched from 1931 were adapted for carrying aircraft which allowed to effectuate long-range reconnaissance. These submarines were built with a gradually larger size, until arriving to the I-13 class ordered in 1943, whose units had an operational range of 17700 nautical miles in surface and a displacement of 4838 tonnes in immersion. However, the dimensions of this class were later surpassed by those of the I-400 class.

Submarines I-15 and I-400
[1] From the standpoint of naval construction, the submarines of the I-15 class solved reasonably well the problem of carrying aircraft onboard submarines. [2] Like other ambitious projects, the very large and vulnerable submarines of the I-400 class, whose role was not clearly defined, were disappointing in every aspect.

Equivalences in the designation of Japanese submarine classes
Type designation Numeral designation
Kaichu I Ro-11 class
Kaichu II Ro-13 class
Kaichu III Ro-16 class
Kaichu IV Ro-26 class
Kaichu V Ro-29 class
Kaichu VI Ro-33 class
Kaichu VII Ro-35 class
Junsen I I-1 class
Junsen I Mod. I-5 class
Junsen II I-6 class
Junsen III I-7 class
A I-9 class
A Mod. 1 I-12 class
A Mod. 2 I-13 class
B I-15 class
Mod. 1 I-40 class
Mod. 2 I-54 class
C I-16 class
C Mod. I-52 class
Kaidai I I-51 class
Kaidai II I-52 class (later I-152 class)
Kaidai III a I-53 class (later I-153 class)
Kaidai III b I-56 class (later I-156 class)
Kaidai IV I-61 class (later I-162 class)
Kaidai V I-65 class (later I-165 class)
Kaidai VI a I-68 class (later I-168 class)
Kaidai VI b I-74 class (later I-174 class)
Kaidai VII I-76 class (later I-176 class)
Kiraisen I-21 class (later I-121 class)

~ History of the submarine weapon (XI) ~

~ History of the submarine weapon (XIII) ~

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