An economic, high performance bitumen paint containing Gilsonite and synthetic resins, for the anticorrosive protection of the underwater hulls of canal boats, with a glossy finish. This type of product is often called ‘blacking’ and is widely used for canal boat maintenance. It gives excellent protection in both fresh and salt water. It has good abrasion resistance, coupled with good flexibility to resist cracking and damage. It can also be applied to weathered masonry to give excellent moisture protection. This is a bitumen-based coating, do not apply a tar-based coating (such as Coflex) over it at any time.