I am replacing the transom wood on my aluminum Crestliner. The boat spends all summer in a freshwater lake. Previous owner replaced fasteners with steel and corrosion of the aluminum is present. What is the members experience using stainless fasteners?
Thank you.
My Grumman aluminum canoe had some stainless steel to aluminum corrosion where the seats were fastened. It’s about 60 years old.
But I recently helped re-rig a sailboat that had last been done 20 years ago. The rig is all aluminum with stainless fasteners. When it was last rigged in the 90’s the owner bedded everything using marine silicone. All fastener threads were smeared before fastening. It’s a saltwater boat and sits all season on a mooring. Everything easily came apart and there was no evidence of corrosion. I’m sold on this process.
My alumacraft has stainless fasteners on the transom and from the factory they isolated screw and nut heads from the aluminum using nylon washers. That’ll work.
If you are overly worried check out Non Ferrous Fasteners. They have all kinds of cool hardware.
So long as the parts are electrically insulated, you’ll be fine. Nylon washers between the SS ones work decently, especially with some sort of dielectric grease between the parts.
This is going to draw flames, and there are numerous grades of "stainless" steels.. but..
Typical SS is really a junk material for high-stress fasteners.. I’d avoid it, if at all possible. In particular, SS nuts on SS screws have a very annoying tendency to gall and lock-up under heavy torque. You’re better off with quality galvanized steel hardware, some anti-seize and a shot of paint.
In freshwater use, there should be no issues at all.
The presence of an electrolyte (any water outside of a lab) should cause galvanic corrosion.
In this part of the world, we still have "Lab" clear water. Just talking practicality and experience, not what the textbooks say. I just replaced the transom in my 72 Mirro-Craft. Originally done with SS fasteners. No corrosion present, so did it again with SS.
If I was a salt water sailor, I would expect different results!
Sikaflex products are what you want to use for bedding and sealing compounds above and below the waterline.
When I worked building waterslides, every stainless 3/8" bolt holding the tube sections together was given a dab of Sikaflex to prevent galling while being tightened with an impact wrench. Out of the thousands of bolts used, I can only recall one which jammed while being tightened. Since we couldn’t get it undone, it’s still in place, right where we left it.
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