KeelShield Self Adhesive Hull Protector 1 Keel protection for your boat. The keel of your boat is the most vulnerable part of your boat and is susceptible to damage from concrete, docks, beaches, and rocky shores. It is the center line running down the bottom of the hull of your boat. It is a structural element designed to allow the boat to stay upright and slice through the water and is the first contact with the water but also a vulnerable spot for damage. Hull protectors provide the shield yo