Sounds to me like a not really bronze alloy, more like brass and
de-zincification. De-zincification happens in copper/zinc alloys in seawater
because the copper and the zinc form a battery wherein the zinc disappears
leaving weak, spongy copper. Copper and tin, as in bronze, are much closer on
the galvanic scale so this doesn't happen.
I don't recall if your fitting was bonded, connected to other fittings with a
wire. Bonding increases the possibility of electrolysis and/or galvanic
corrosion.
Personally I don't have thru-hulls. I use the Wilcox flanged base sea cocks
and bolt the flange to the hull with bronze carriage bolts. The thru-hull
fittings just constrict the water flow and are not needed to protect my hull so
I don't use them. On a wooden boat they must be used to protect the wood from
ship worms.
I have seen valves screwed onto thru-hull fittings with some of the unsupported
thru-hull between the valve and hull. This is a very weak situation. The
metal left on the thru-hull after cutting the threads is much too thin to stake
your boat on in my opinion. Imagine stepping on the valve in a heavy sea, or
having something heavy falling onto the valve.
Norm
S/V Bandersnatch
Lying Julington Creek FL
30 07.72N 081 38.4W
----- Original Message -----
From: Lee Haefele
To: [email protected]
Sent: 4/29/2008 10:10:51 PM
Subject: [Liveaboard] Through hull fittings
I had a 1.5" through hull fitting break off in my hand. It was pink/orange and
granular at the fresh break. Is this electrolysis and will all of the through
hulls be equally bad? None are grounded, boat was built 12/99. How could I
test the others? If I file a corner off, will the odd color show?
Lee Haefele
Leopard 38 cat, Alesto 2.
_______________________________________________
Liveaboard mailing list
[email protected]
To adjust your membership settings over the web
http://www.liveaboardnow.org/mailman/listinfo/liveaboard
To subscribe send an email to [EMAIL PROTECTED]
To unsubscribe send an email to [EMAIL PROTECTED]
The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/
To search the archives http://www.mail-archive.com/[email protected]
The Mailman Users Guide can be found here
http://www.gnu.org/software/mailman/mailman-member/index.html
