Steel is a heat-treated alloy based on iron with a lower carbon content and small quantities of other elements. The high strength of steel in relation to the plate thickness and the ability to cut and bend it into many different shapes makes it suitable material for building hulls and superstructures. Fastenings such as bolts and rivets are often a different alloy for added strength, while fittings contain added chromium, to make the steel ‘stainless’ and resistant to rust. Having stated that steel is a good material for building boats, it is important to be aware of some of the characteristics of the material in order to ensure good results.

Steel corrodes
The most common form of corrosion in steel is rust. For the reaction to take place, water must also be present. The marine environment is therefore an ideal place for rust to occur.

Steel stretches
Due to the high flexibility and strength of steel it is hard to break, but impact damage may well result in a dent owing to the metal stretching and deforming locally. This can present problems for a protective coating, which may not be so flexible.