For the cases where it is tough to get that close, loop back to the COB, park then throw the throwable with a line attached. You won't need to drive close enough to hit/scare them...
Along that same line I had been thinking that you could trail the throwable (or anything that floats) on a long, floating line behind the boat and just sail in a circle around the person in the water. That way the line comes to them, and they can grab it, and you can pull them in to the boat. It's the same way a waterski tow boat gets the tow line back to a skier who has fallen.
