TUBE KEEPER - Secure Towables to Your Boat for Safety! Tired of lying on top of your tubes to keep them from flying out of your boat? No place to sit? Tube Keeper to the rescue! It saves essential passenger space and prevents serious injuries by securing towables to your boat’s stern. Simply attach the straps around the tube’s handles. Then attach with either the giant 3-1/4 in. suction cups or loop the stretch cords around a cleat or rail. The 2 in. wide adjustable straps are easy to tighten for a secure hold.