For 12v I’d suggest the Graupner #1951 pump, and we make the P91 RC switch specifically for this job.
I hesitate to recommend any particular radio as I’d probably get jumped on by users of other sets (rather like the wife asking which dress she should wear and then demanding to know what’s wrong with the one you didn’t choose….).
Personally I’d go for either a Spektrum DX6 2.4GHz or, if you’re flush, one of the Graupner-JR “MC” sets or the Robbe-Futaba F series. For a budget set there’s the DX5e or a very cheap and cheerful 2.4GHz set from Giantcod. Avoid 27MHz altogether (sorry, Ashley) and don’t opt for 40MHz if there’s a large number of folk who sail where you plan to go.
All my current sets are 40MHz Hitec apart from the DX5e. I had a Futaba 6EX 2.4GHz but I didn’t like it and passed it on.
Hope this helps
DM