Lanolin or mineral oil under shroud rollers is also good. Just rinsing stainless with fresh water whenever you can will lessen the corrosive effects of salt water. When surveying for stainless corrosion, don t be distracted by stains. Contrary to what the name implies, the stuff does stain, mostly from bits of mild steel scraped off the extruding dies when the wire is formed. But do look closely, preferably with a magnifying glass, for any sign of pitting in the metal the surface will seem to have teeny-tiny craters in it.
Any significant pitting is cause for replacement.
When in doubt, proof-test, running the wire up to 50 percent of its rated strength on a testing machine. If nothing breaks, it was a relatively cheap way to check. If it breaks, you ll feel very prudent for checking. Proof-testing is a good idea after five to ten years in northern climates, or three to five in the tropics, even without evidence of pitting, just to make sure the wire hasn t fatigued or suffered other damage. We usually recommend to customers that they seriously consider replacement of the rigging within these timeframes.