Originally posted by properchopper
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You got that 100% right. Since the bolts and blind nuts are (in most cases) dissimilar metals, galvanic action + the corrosive effect of water penetration will corrode the nuts to the blind nut and (quoting Mr. Davis : "The blind nuts weren't holding the fin at all anymore. Just spinning. When I got in they were basically to circles of useless rusty dust.")
Man this brings me back to the dark ages when I ran in salt water behind my 40 foot liveaboard. Still have memories of grinding stuff off. Bah Humbug.
A comment on doubler material :
I've found that most factory transom internals (e.g. DeltaForce hulls) are reinforced by a thin layer of what appears to be compressed and solidified chicken feathers. To supplement that, a doubler will add strength BUT HERE'S A THOUGHT : Most transom internals aren't a 100% flush/flat surface SO by using material like CF there will be voids between the CF and the factory material AND then when tightening the hardware there is a risk (small, but existent) of drawing the hardware to the stiff internal doubler and possibly cracking the external gelcoat. For that reason (and for economics) I always use 3/32" birch ply which I tack into place with silicone dots and then being somewhat flexible it'll become drawn into the voids, not the external hull surface.
And to make starting the nuts easier, I use a teensy blob of 3M strip caulk on the end of my finger then use an appropriate size nutdriver. (I also keep Neosporin and Band-Aids close by
)
Man this brings me back to the dark ages when I ran in salt water behind my 40 foot liveaboard. Still have memories of grinding stuff off. Bah Humbug.
A comment on doubler material :
I've found that most factory transom internals (e.g. DeltaForce hulls) are reinforced by a thin layer of what appears to be compressed and solidified chicken feathers. To supplement that, a doubler will add strength BUT HERE'S A THOUGHT : Most transom internals aren't a 100% flush/flat surface SO by using material like CF there will be voids between the CF and the factory material AND then when tightening the hardware there is a risk (small, but existent) of drawing the hardware to the stiff internal doubler and possibly cracking the external gelcoat. For that reason (and for economics) I always use 3/32" birch ply which I tack into place with silicone dots and then being somewhat flexible it'll become drawn into the voids, not the external hull surface.
And to make starting the nuts easier, I use a teensy blob of 3M strip caulk on the end of my finger then use an appropriate size nutdriver. (I also keep Neosporin and Band-Aids close by
)
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