All Steel conforms to EN10025 / BS4360 and with the exception of the base plate is pickled and oiled.

In layman’s terms during steel production the surface of the steel becomes coated with black iron oxide called mill scale, this needs to be removed prior to applying paint or blacking. In the good old dark ages this was done by weathering, leaving it in the open to rust and then sandblasting off the rust along with the mill scale and quite often a lot of the metal too!

Pickled and oiled steel is a more modern solution the steel is first pickled in a chemical bath to remove the mill scale and then covered with oil to prevent rusting. This process does increase the cost of the steel but is offset by the superior finish achievable on the hull without sandblasting.