"Glenn Ashmore" wrote in message
news:gDuDb.5356$JD6.2598@lakeread04...


Doug Dotson wrote:

I don't trust plastic below the waterline. Marelon is
plenty strong but bronze is stronger. I have to install
a few more thru-hulls this spring. I guess I'll have to
do some thinking about it.

I had the same worry before I decided so I tried (as my compulsive
engineer personality requires) to analyze the threat. Corrosion is not

clip

I tried to visualize what would cause a significant side impact on a
throughhull, probably in a knock down or roll over and came up with a
battery breaking loose, an anchor stowed loose in the bilge. So I found
an old used Forespar 1 1/2" seacock on ebay, mounted it on a piece of
1/4" steel plate and whacked it on the side with a 5 lb sledge. First
blow had no effect. Second blow produced a small crack about 1" long
leading from the valve stem. Third blow broke a bolt flange and
lengthened the crack some but it was still well attached to the
throughhull. I have beaten enough bronze castings to pieces to fit in
my crucible furnace that I don't believe a bronze throughhull would have
held up but a little better.

I thought this was about Marelon - did you do the same thing to one of
those? If so, what was the outcome? I like the concept of Marelon, if only
because it can't rot and ought to move more reliably...

L8R

Skip

--
"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail away
from the safe harbor. Catch the trade winds in your sails. Explore. Dream.
Discover." - Mark Twain