i was unfamiliar, now i am. thank you.
so once the rigging is replaced is there a way to prevent crevice corrosion? similar to external zinc or painting the wire rope and inside of swage before the swaging maybe..
i read that insulation may or may not be good, it may trap and increase corrosion inside.
No, it's a fundamental property of stainless steel. Any rigger worth a damn is already doing everything that can be done, such as filling the swages with liquid resin or epoxy before inserting the wire in order to reduce the possibility of water penetrating. The rigging is a concern, but another area that's prone to this problem is keel bolts. Lead keels are usually attached with embedded stainless steel bolts, and in time all keels will leak a bit of water into the area between the keel and the hull, allowing stagnent, oxygen deficient water to surround the keel bolts. The disturbing thing about crevice corrosion is that it happens fast. Once it starts, it progresses very rapidly.
If that's not enough to keep you up at night, then there's the hidden corrosion that comes from the fact that all the points where the shrouds attach to the mast are usually stainless steel, in direct contact with the aluminum mast. This results in galvanic corrosion, which is most likely occuring on the inside of the mast, where you can't see it. You can prevent it by using an insulating material between the stainless and aluminum, isolating them from each other, but production builders of boats like ours don't generally do that, because it adds cost, and it will be ten or twenty years before a shroud mount will pull through the side of a mast. Long after the warranty is up.
So if you want to really, truly go "offshore," make sure your standing rigging is replaced regularly, and don't forget your annual or bi-annual rigging inspection by a qualified rigger, which must include a trip up the mast. I guess you can take some comfort in the fact that while corrosion will get you eventually, most people do in fact manage to make it back alive most of the time. But the odds tend to start decreasing the further into your rigging's second decade you go.
