thats been used since the 70s. it was pretty popular to send a rc boat out with your line as it go under trees docks etc etc, they used the electric ones in Japan with a rc servo to disconnect the line from the boat.
this is where I was shown the idea it was like 10 mins from the house on the base in japan.
one of the most prettiest places in the world, especially in the spring.
You can easily add a servo to most mid to higher end rc boats. I would add one off either side of the boat as to not interfere with your line. Some have really good range. Just wondering if it would be beneficial to have an electric propelled boat due to the noise of the small 2 stroke engines...
Not to steal the thread but here's a interesting thing we'd do in the saltwter in mexico. Guy with snorkel equip grabs the line of someone on shore baited with cut bait. Swims out until he see's a nice grouper or snapper then drops the bait in front of there nose. Gives thumbs up that bait was dropped. Stays on surface and pumps fist in air to let you know the fish has taken bait. We caught some mighty fine fish this way, give it a try next time your fishing the salt you won't be disappointed.