Hi Woodsie,

Try to find a club in your heighborhood that runs boats, or go to a venue, racing day, whatever, to see some boats in action, to help you make up your mind.

As far as swimming after a boat goes, I'm no great fan of swimming after mine too, at least not this time of year...
I run my boats with a speedcontroller that has a low batterie detection built in; when the batteries drop below a certain level (you've already noticed the drop in speed), the ESC cuts the power to the motor, only allowing half throttle to get back to shore, works like a dream.

Large bodies of water are fun to run fast electrics in, just make sure your boat is taped shut waterproof, as the seemingly small waves reach "oceanic" proportions for an electric speedboat running full speed.

Regards, Jan.