Of course, building a Soviet Fleet in-general (even if you could send it out into the world’s oceans) is usually about 99.8% useless.
If you’re dead-set determined to build a great Soviet Navy to rule the waves and invade Japan with, there’s really only about two choices you have.
A) Capture Berlin, build fleet there, be the envy of the Allied Navies
B) House-rule in that you can build Industrial Complexes in 1941… Charge 15 IPCs and place a complex on the board so you can build a navy or whatever else (I know 1941 doesn’t come with them, you can literally use anything to denote an Industrial Complex, from an A&A complex used from a different version of A&A to Monopoly Hotels or even a Penny, it doesn’t matter, as long as everyone agrees what you’re using for Industrial Complexes).