I agree it would be hard work but, just think it would be an interesting idea. The Atlantic Sharks modding crew are attemping to convert SH4 and SH3 into one game by basically porting in as much of SH3 into SH4 as poss and modding new subs etc for the U boats. So you get the graphics of SH4 but with the game from SH3. If they manage it, adding Royal Navy subs to SH4 may well be a posibility.
If you look on the GWX thread on the SH3 mod forum they have some very nice RN sub models that they plan on adding to the final GWX version. Once everybody has figured out the process for creating new units from scratch in SH4 would not be a great leap to adding them in the existing pacific campaign for use in SE Asia. Perhaps first as AI controlled maybe later as a player contolled sub? I don't know how realistic this is just speculation on my part, I don't know very much about how to go about creating anything like this techwise though.
RN subs have never been simulated in a computer game AFAIK (ok GWX does have some lend lease S boats as AI subs). Admittedly they weren't as numerous as the U boats or as glamourous as the US fleet boats (RN subs are a bit on the ugly side too
) and they didn't sink the tonnage, but they served all over the place and IMO they are a bit of a forgotten chapter in WWII naval history.
Anyway doesn't hurt to kick a few ideas around see where they go.:hmm: