If the range is 300m or 500m and oops, it gets blown outside the range, what happens next? It hovers, or lands--and drowns? Or is smart enough to find a way home?
Some have GPS, but to land on a boat with all kinds of cables, ropes, lines, masts, movement etc, would be impossible.
I have a quadcopter like the one in the picture, except it is a lot more powerful. They are fun, but like has been mentioned before, the batteries are a really big limiting factor. Even the one in the picture will only realistically get about 15 minutes of flight time max. If you hovered in one spot you could maybe get 20. If you attach any extra weight, you quickly get down to 8-12 minutes flight time without even flying crazy. You can get a tri copter to fly a lot longer, but then you are very limited on weight.
The range is actually a lot further than one can fly. Mine isn't even the most powerful and I could get two miles range without a problem.
The other thing that was surprising for me when I first flew was how bad the camera quality is that is transmitting to your googles or screen. The GoPro is attached and viewed only after you land. You can set them up to transmit, but it becomes very poor quality as well. You can barely see anything until you are right up on it and it is too late.
These things are just so easy to crash and susceptible to interference. The ones that have a safeguard to fly themselves in an emergency are just as likely to crash when you haven't activated the failsafe or experienced a failsafe.
It is fun, but I wish I never bought mine. **** breaks all the time or glitches out and crashes are really expensive.