To backing-plate or not, that is the question

[brak]

I am replacing thru-hulls on a 35 y/o boat. The ones currently there are, probably, not original but are getting long in the tooth (larger one's have "rounded" edges, which I am guessing is a result of corrosion eating at them). That said, thru-hulls appeared to be solid and at least one took hours to saw through (by hand, I don't want to gouge the hull with power tools). Thanks to whoever installed them for not using 5200, btw

Anyway, the previous thru-hulls had no backing plates. The hull fiberglass thickness is somwhere between 5/8" and 3/4", so there is a lot of glass. Hull is relatively flat where thru-hulls are installed. I am struggling with whether backing plates will do more harm than good. I have some teak for the purpose, which I can probably seal with epoxy. Still, over long term I wonder if teak would not deteriorate faster and then cause seal issues?

Ideas?

[Tartan34C]

No need for backing plates in this application.
All the best,
Robert Gainer

[sailingdog]

Given that the hull is that thick and that the inner hull surface is relatively flat, I would have to agree that there really is no need for a backing plate.

The only question I have is have you check to see if the hull there is solid laminate. Some boats have cored hulls, if yours does not...then don't worry about it... if it does, then you should make sure the area is solid glass rather than cored laminate.

[brak]

No core there - all glass, and looks fairly green even at the cut of the thru-hull. I had to pay all that money for something, and mainly I paid for a hulk of glass

Well, thanks guys - this was my feeling too but I prefer to get a second opinion!

[sailingdog]

Have fun...

[RickLaPaz]

Originally Posted by sailingdog

Have fun...

You sir, are pure evil.............