On Tue, 26 May 2015 21:23:23 -0400, Wayne.B
wrote:

On Wed, 27 May 2015 06:38:35 +0700, Bruce in Bangkok
wrote:



I am in the process of building a permanent mooring and have a heavy
galvanized anchor as well as several lengths of galvanized and
stainless. However I have heard stories about rapid galvanic corrosion
when connecting stainless and galvanized together under water.

My question is, can I (should I) connect the heavy length of stainless
chain to a lighter length of galvanized chain and to the galvanized
anchor using stainless shackles and swivels? Or with galvanized
fittings?

I would normally plan on inspecting the mooring on a annual basis.

The reasoning in mixing materials is basically that I've got the two
lengths of chain and if useable need only to buy the shackles and
swivel.

Anyone with personal experience or specific knowledge of joining
stainless and galvanized in seawater?

===

Some people have reported problems but I've been using a stainless
steel swivel with galvanized chain and galvanized anchors for the last
11 years and 42,000 miles of cruising with no issues. My personal
philosophy is to make everything a lot stronger than it needs to be
and inspect it regularly. So far so good. Like aluminum, not all
stainless is created equal.

Yes, I did the same. I even had a short length of stainless chain,
about 6 feet, at the anchor end of the chain rode so when the anchor
was in the chocks the chain laying across the deck wouldn't get rusty
:-)

But, the anchor was actually in the water for limited periods of time,
maybe a couple of days and than we'd up anchor and go the next island.
A couple of days and than on our way again. "At Home" we would be tied
up to a jetty.

I somehow feel that this may be a different situation as the boat is
going to be on the mooring for an extended time and while I expect to
inspect the mooring at least once a year I may well be away from the
boat for several months at a time. We were away for nearly six months
this time and I really don't want to be wondering whether that swivel
is going to hold :-)

I did look at the Galvanic tables and Stainless and zinc are miles
apart, but then zinc and steel are nearly as far apart. What I've
about made up my mind to do is stainless shackle from stainless chain
to the anchor which isn't galvanized and galvanized shackle from
galvanized chain to over size stainless swivel. The stainless chain is
long enough to haul the end up to the surface so I can check the
swivel and the galvanized and stainless chain shackles and since it is
stainless to non galvanized anchor on the other end that shouldn't be
a problem.

I hope :-)
--
cheers,

Bruce in Bangkok