Dixon’s range of Arctic Steel Thru Hull Skin Fittings are truly designed for underwater applications as they are cast in Duplex 2205 stainless steel, making them significantly stronger and more corrosion resistant than 316 fittings. Stainless Steel Industry consensus is that commonly used austenitic stainless grades AISI 304, 316 & 316L are suitable for coastal service environments, splash zone applications and intermittent submersion in seawater. Times have changed and now Duplex 2205 stainless steel is the material of choice when coming into permanent contact with seawater; according to the International Stainless Steel Forum.

Australian Stainless Steel Development Association says the following general rules apply: – 304 may be used for fully exposed components, frequently washed in fresh water – 316 may be used for all hull and deck fitting applications above the water line – 2205 offers higher strength and therefore lighter weight components for the same applications as 316 and can additionally be used up to 60°C for wet exhaust systems and fully submersed applications.