Razz, if you go to Paul's Fishing Kites, they have a special spring loaded clip that will detach the baited line from the deployment torpedo once the required distance has been achieved. This allows the machine (?)to be be brought to shore on it's own line without interfering with the live-bait and the line and rod is is attached to.

Great idea, it looks as if you have put a lot of thought into the design. Innovation is the mother of invention.