Hi David,
Unfortunately we don't know which part of the country you are in. I.c. as a form of power is very much in a minority nowadays for various reasons, however there are still a few lakes and clubs which are still active in this part of the hobby.
If you buy Model Boats magazine there is a regular item, BMPRS News, which covers the racing section of the hobby, mainly around Nottingham and the Midlands.
**LINK**
It would be worth checking the MPBA website and perhaps contacting them to find a club in your area who would be active in the racing or offshore.
**LINK**
Hope this helps, and welcome back to the hobby.