https://www.yxtechco.com/marine-metal-fabrication.html Boat Metal Fabrication What are Common Marine Grade Metals? When metal is exposed to water or moisture, marine-grade metal may be needed to prevent the material from failing under the conditions. To be considered marine grade, the material must be able to resist the corrosive effects commonly found in water environments. To achieve this, special alloying elements are added to these grades to prevent corrosion.