Have tried a little rust colour on the top plates but not happy. So will coat with natural steel colour and then rust them up.
Before you say that it should be cast iron not steel - its only a model and think it will look better. Also the clever people are still arguing about what covered the ship - some say wood planks and iron darts, others all iron - so just being a simple modeler its read your research and take your pick. They also say that the top was covered with straw so the people jumping onto the ship did not know what was a metal dart and what was safe to land on - but I like the model without straw.