Thru-Hull Fittings       Faulty thru-hull fittings are by far the leading reason boats sink. Inspect your thru-hull fittings on a regular basis. Make sure all of these fitting have a shut off valve attached to them that's in good working order. All hoses attached to these fittings should be secured with 2 hose clamps and 5200 Marine Adhesive. And finally make sure that your bilge pump works, test the float switch and make sure it's going to work when you need it. Back