Hi,

I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?

Thanks,

Mike.
Beaufort, NC

Hello Mike,

Yes, the galvanized coating on the chain will be sacrificed
to protect the stainless anchor. It is generally not
recommended that you use galvanized chain with a stainless
steel anchor. Used continuously as a mooring would be
particularly bad.

If you must, here are three things you can do:

1. Use nylon rode for the first 50 feet from the anchor. At
that distance, the stainless will not corrode enough zinc to
notice. You could probably skip the next two steps if you
did this.

2. Attach a sacrificial zinc directly to the anchor, making
good electrical contact. Easier said than done, perhaps. The
problem with this is that it will need to be replaced maybe
once per year. Worse, you may have to pull it up more
frequently at first to verify that the zinc is working and
your chain is surviving. It would also be good to devise a
system to prevent the chain from touching the anchor. You
want the zinc anode to be closer to every part of the anchor
than the chain is.

3. After attaching a sacrificial zinc to the anchor, paint
the anchor with an epoxy paint intended for such use. There
are some epoxies designed for painting props that would
work. Be careful not to paint the zinc anode! Buried in
seabed muck, the anchor might have a long a productive life.

Of course, you could use stainless chain. It might be cheaper.

Good luck!

Chuck













wrote:
Hi,

I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?

Thanks,

Mike.
Beaufort, NC

Mike, let me offer a clarification and a correction to my
earlier post.

The clarification is to say that the chain will not corrode
UNLESS it is in contact with the anchor. It is quite
possible that at times the links will arrange themselves so
as to avoid making an electrical circuit with the anchor.
But if and when they do, then the very thin galvanizing
layer on the chain will corrode fairly quickly. And as is
often the way of nature's seeming perversity, the links
closest to the bottom (the anchor)and least accessible will
deteriorate first.

The correction is to drop option #1. The idea was to avoid
allowing the chain to contact the anchor, but upon awakening
from what must have been a dream, I see that it makes no
sense at all. The point is that if the chain doesn't contact
the anchor, however you achieve this, you won't see corrosion.

I've only been talking about galvanic corrosion. Both the
chain and the anchor will self-corrode even if they are made
of the same material.

Chuck


chuck wrote:
Hello Mike,

Yes, the galvanized coating on the chain will be sacrificed to protect
the stainless anchor. It is generally not recommended that you use
galvanized chain with a stainless steel anchor. Used continuously as a
mooring would be particularly bad.

If you must, here are three things you can do:

1. Use nylon rode for the first 50 feet from the anchor. At that
distance, the stainless will not corrode enough zinc to notice. You
could probably skip the next two steps if you did this.

2. Attach a sacrificial zinc directly to the anchor, making good
electrical contact. Easier said than done, perhaps. The problem with
this is that it will need to be replaced maybe once per year. Worse, you
may have to pull it up more frequently at first to verify that the zinc
is working and your chain is surviving. It would also be good to devise
a system to prevent the chain from touching the anchor. You want the
zinc anode to be closer to every part of the anchor than the chain is.

3. After attaching a sacrificial zinc to the anchor, paint the anchor
with an epoxy paint intended for such use. There are some epoxies
designed for painting props that would work. Be careful not to paint the
zinc anode! Buried in seabed muck, the anchor might have a long a
productive life.

Of course, you could use stainless chain. It might be cheaper.

Good luck!

Chuck













wrote:

Hi,

I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?

Thanks,

Mike.
Beaufort, NC

Chuck,

Thanks for the info.

What do you think the best anchor, metal type, and chain type would
make the very best mooring - and hopefully an inexpensive option.

Mike.

Hello Mike,

Your best bet is probably to check with other boaters in
your area to see what they're using for mooring anchors.
Could be tubs of concrete, concrete blocks, or even rocks.
What is best will depend on the kind of bottom you have.

For chain, it is a matter of economics. Depends on size of
boat, depth, etc. Hot-dip galvanized chain will last much
longer than electroplated chain and it costs more. But
you'll want to inspect the chain and its attachment from
time to time. If the chain is new, two to three years might
be the right interval. If someone is diving to check the
boat, he can check the chain as well. Just make sure all the
fittings are of the same material.

Good luck!

Chuck


wrote:
Chuck,

Thanks for the info.

What do you think the best anchor, metal type, and chain type would
make the very best mooring - and hopefully an inexpensive option.

Mike.

Somebody wrote:


I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?

There is.

Install a monel or equal link between the S/S and the galvanized items.

Lew

Hello Lew,

The monel link wouldn't prevent the galvanized chain from
coming into direct contact with the anchor. It would be a
great solution if the chain could be held taut and away from
the anchor.

Chuck

Lew Hodgett wrote:
Somebody wrote:


I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?


There is.

Install a monel or equal link between the S/S and the galvanized items.

Lew

This is a thick mud/sand bottom, mostly mud. WIth reversing tidal
current (4 knots) I expect the 90 stainless plow to dig in pretty deep
within the first week or two (i'll be keeping a good eye on it during
that time) -

Chuck, it seems to me that with an achoring setup like that, the chain
may very well be held away from the anchor and the monel link might
work.

What do you think - am i being too optimistic (stainless chain and new
anchors are expensive)

Thanks,

Mike.

Would that really help?
I thought that if the two dissimilar metals were electrically connected, you
had a problem. Hanging a zinc guppy overboard will sacrifice the guppy, so
why wouldn't the galvanized chain be sacreificed even if it was seperated,
but electrically connected?
Electrolysis can be a real problem. I had a bridle w/ almost all ss parts:
chain hook, ring, shackles and thimbles. Everything except about 5 links of
galvanized chain between the chain hook and the shackle connecting to the
ring. Those links quickly became rust, so I replaced the ss with galvanized.
Of course, all this was in direct contact with each other, but I suspect
that electrical contact is enough to creat a problem.

"Lew Hodgett" wrote in message
ink.net...
Somebody wrote:


I just found a 90 pound stainless steel plow to use as a mooring
anchor. The guy I got it from said that he thinks there is an
electrolysis issue if you use galvanized chain. He said that there was
something I needed to do, but couldn't remember what.

Anyone have any clues for me?

There is.

Install a monel or equal link between the S/S and the galvanized items.

Lew

Rather than use a ss plow $$$ for a mooring, get 3 over-sized Danforths
spread out 120 degrees and leading to a central point with a swivel and a
short chain to the buoy.
I found that the chain becomes a more significant cost, so increase the
anchor size and get by w/ less chain.
With anchors, the mooring can be more easily raised and inspected. At least
in the mud my mooring was set in, there was no detectable wear on the anchor
or chain at that end (the labels were still on the anchors after a dozen
years) . The chain does wear close to the middle (at the swivel), but you
can replace those sections w/ new chain and clevis connecting links.

wrote in message
ups.com...
This is a thick mud/sand bottom, mostly mud. WIth reversing tidal
current (4 knots) I expect the 90 stainless plow to dig in pretty deep
within the first week or two (i'll be keeping a good eye on it during
that time) -

Chuck, it seems to me that with an achoring setup like that, the chain
may very well be held away from the anchor and the monel link might
work.

What do you think - am i being too optimistic (stainless chain and new
anchors are expensive)

Thanks,

Mike.