Stainless bolts on a sailboat are often the first thing that sufferes from crevice corrosion
. They are typically under enough stress to cause what's called stress crack corrosion
, plus the threads are prime candidates to start crevice corrosion. This is a pretty big subject, and there are a lot of seperate things that work together to cause stainless corrosion.
There aren't really the same type of proof bolts in stainless as there are in steel
. That is because the stainless grades are much more descriptive than occurs with steel
alloys. So for instance a 316 bolt from almost anyone is going to be very close in properties to a 316 bolt from anyone else. With steel that isn't true, there are hundreds of steel alloys (if not thousands) so proofing is pretty necessary.
That being said, there are a number of stainless grades, and you need to know what you are replacing to match it. Or go with the strongest option you have available. That being said most boat manufacturers use either 304 or 316.