Glider
Captain
True but if we are working on the basis that there is no war in Europe then its a safe bet that a good number of the RN's more modern boats would have transferred. Also numbers are not everything.Shifting back to ships.
The Japanese had 63 (?) Subs on active service on Dec 7th 1941.
There were about 5 boats at Kure assigned to training/local defense.
Combined fleet 14 boats
RO-33 & RO-34
1935-37, 700 tons, new torpedoes.
I-53 thru I-60 and I-62 and I-64 thru I-66
1927-32, 1575-1635 tons
3rd fleet had 4 boats assigned to blockade/transport
I-121 thru I-124
1927-28, 1142 tons, mine layers.
4th fleet had 9 boats assigned to the Japanese Mandate Islands RO-60 thru RO-68,
1923-27 boats of about 990 tons. old torpedoes.
5th Fleet had 26 boats.
I-1 thru I-6
1926-35, 1900-2080tons, two with float planes.
I-15 thru I-26
1940-41, 2184-2190 tons some with single floatplane.
I-68 thru I-75
1934-38, 1400-1420 tons
In Dec 1941 the Japanese had a further 29 boats under construction, to complete in 1942-43 and another 38 approved but not yet started.
The US had 111 boats in commission with 73 under construction but only 51 in the Pacific. 29 at Manila (6 S boats) and 22 at Pearl Harbor (6 S boats)
The Dutch had 12 boats of different ages.
The RN had 0.
I53 to I66 were all assigned to training by 1942, the larger boats were at a significant disadvantage being large and slow to submerge. The others would have faced quite well equipped and trained excorts whereas the RN boats would have faced little effective defences and quite probably have a field day with a convoy