Just an idea but could you make a safety release on the boat so say after 2lb of pull on the line it would release. Maybe another servo so you can drop the line when you need to, think this would work vary well for you and save your boat to. Get a fish drop line pull fish in drive boat to shore reconnect line and send it out agene [8D] bringing the fish in with the boat still connected would be a pain in the but. Was thinking something like a dead bolt for the latch with a servo simply a piece of wire throe 2 prices of tubing where the line would fall throe the gap between the tubing. for the release with out a servo simply a hinge type flap with a magnet at one end that would hold the line then with enough force on the line release it (over coming the magnet) and letting the line go, to connect simply put the line in place and flip the magnet into position (or metal hinge)