RE: [Paddlewise] Corrosion

Hi All,

Digging back in memory to my boat yard days I believe that the primary
corrosion protection for steel hulls is in fact the paint.  Ralph is correct
in mentioning the sacrificial strips that are welded to the hull, commonly
on the rudder.  These are usually Zinc, though I guess sometimes aluminum is
used.  They are used to prevent electrolysis or galvanic corrosion caused by
the ships electrical system and the way it interacts with dissimilar metals.
Keeping fresh zincs on steel hulls is vital.  If the paint gets damaged and
you get current flowing it really raises hell with the ship.

I don't really remember much about this phenomenon, except that laying on
ones back, on a marine railway, in February, in Maine to weld zincs on a
nasty old seiner is not nearly as much fun as paddling.
Cheers,

Rob Cookson

> -----Original Message-----
> From: owner-paddlewise_at_lists.intelenet.net
> [mailto:owner-paddlewise_at_lists.intelenet.net]On Behalf Of ralph diaz
>
>
> dmccarty_at_us.ibm.com wrote:
> >
> > So how do steel shipowners prevent rust.  Is there anything
> special in the
> > steel used in ship construction to help reduce corrosion?  Or is it just
> > paint and chip, paint and chip......
>
> Although I have no real need to know how the following works and so I
> don't, I have noticed in the marine catalogs some items that are
> basically sacrificial metal devices that will corrode faster than vital
> parts made of metal.  They draw corrosion induced by electrical charges,
> I think.  Perhaps the best thing to avoid corrosion of your knife and
> other vital metal items in a kayak is to wear one of these and also use
> a small battery that will create whatever polarization (negative or
> positive) that will interact with your corrosion system and affect the
> sacrificial metal item only.  :-)
>
> ralph diaz
> --
> -----------------------------------------------------------------------
> Ralph Diaz . . . Folding Kayaker newsletter
> PO Box 0754, New York, NY 10024
> Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com
> "Where's your sea kayak?"----"It's in the bag."
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