One thing we do to ensure that the coil remains sealed on the Sovereign foam filled is to use a Marine Sealer called 5200. It is available in Marine(boat) stores, comes in a tube like toothpaste, and sticks to anything-especially you!! It dries in 48 hours and WILL NOT leak if you cleaned the area to be treated real clean. We also go up the cable a few inches to make a "strain-relief" as the Minelab cable breaks too easily to suit us. If you can't get this then e-mail us and we will send you some. Thanks, Ed---Scoopman