RE: Thinking of leaving cars for boats
I got away from racing buggies and trucks myself. We have lots of tracks here to race at but the upkeep was killing my wallet.
I'm going to shoot directly to #3. For boat retrieval I use a fishing pole with a top-water lure on it because I had a lot left over from my Bass fishing tournament days. Some just use a reel with a tennis ball tied to the line. I also take along a 2 or 3-man inflatable boat with me. You can pick these up cheaply at most discount Department stores. My current 3-man boat I got for $23.00 including oars. A 12 volt pump will blow it up quickly at a pond if you don't have a lot of room to transport one. A BIG no-no is to go swimming after a dead boat. People have drowned doing this, serious stuff dude.
OK, back to #1 and #2. for Nitro like what I run, they are sometimes a pain depending on weather conditions but most of the time not that much hassle.
I run mine for both racing and fun but I have boats for both. Practicing is for trying out new things such and prop and pipe setups but I like to just plain run them anyway. Rivers are probably the worst place ot run any R/C boat. If they die, they are a bear to get at. River water moves faster than it looks, I know! Use good old common sense when running, stay far away from wildlife, swimmers, full-sized boats, etc. for your safety and theirs.
There are plenty of clubs in the UK, you might want to hook up with one in your area. If you need some help with that, let me know. I know of a few people over in the Motherland.