Abstract: A protective boat hull device is disclosed to prevent damage to a boat hull during beaching. An elongated flexible and waterproof sheet is provided having a length substantially greater than the width thereof, and capable of being wound into a roll along the elongated length thereof for storage purposes. The sheet includes a centering notch extending across the width of one end of the sheet for engaging the front hull of the boat above the water line, in order to center the sheet underneath the hull of the boat below the water line and prevent hull damage during beaching of the boat. The sheet further includes fastening means to facilitate attachment and detachment of the sheet relative to the boat.