Avoid materials such as Cor-Ten or high-tensile steels; they have limited or no boatbuilding applications. Some designers have recommended Cor-Ten in the past, but this steel contains traces of copper, which tends to encourage corrosion in salt water rather than inhibit it. Cor-Ten was developed for use in industrial applications such as water tanks on farm properties. While it resists corrosion in a salt-free atmosphere, it doesn’t have good corrosion resistance when it’s immersed in water, especially seawater.

   Cor-Ten is more expensive than mild steel and it needs to be welded using copper-clad, continuous-feed electrodes and argon-arc. We do not recommend Cor-Ten or other specialty steels for boatbuilding.