Crevice corrosion occurs in the vicinity of spreader tips. This type of corrosion, which is peculiar to stainless steel, can occur on shroud wires or rod as it passes through the spreader tips and under spreader boots. It occurs when stainless steel is kept in contact with stagnant, oxygen-deprived water, such as that which may be found under a spreader boot or antichafe tape.
Because of the hydroscopic nature of timber, the problem is exacerbated where wooden spreaders are employed. Thus, it is vital that spreader boots be removed and the spreader tip and wire or rod beneath be inspected carefully at least annually (this admonition applies to all stainless-steel rigging and rigging components, all of which may be susceptible to crevice corrosion).