Corrosion from Galvanized Chain

F

Fishhawk

New member
Hi all,

After having the anchor and chain on Osprey for only a month I noticed some ugly interaction between the galvanized chain and the stainless bow cleat. It seems there has been a transfer of metal or metal oxide to the cleat. Rather unattractive.

I'm looking for advice. Are ya'll using some other type of chain or can this be somehow avoided? I'm also interested in knowing what is best to use for a quick connection twixt rope and chain.

Thanks in advance for your sage replies.
 
We use a white, I think rubber coated chain for the first four feet from anchor. Keeps damage to a minimum around the anchor cleat, deck and stainless entry to the rode container. Bought it through West Marine.

Jay
 
FishHawk-

Since you're in Minnesota, I'm assuming you're operating in fresh water.

I use 100 feet of GS high test galvanized chain (with 200 feet of three strand nylon tail), a Fortress High Strength Aluminum-Magnesium anchor, a stainless swivel link, a an Quick Aires aluminum/stainless/ and brass windlass, and a Simpson Lawrence stainless pivoting anchor roller without any corrosion between any of the metals, all in fresh water.

I don't understand why you would be getting corrosion unless one of the metal parts is charged with stray electricity, is wet all the time, is exposed to salt water or spray, or one of your components is made up of an inferior grade of metal such as poor quality stainless steel or impure zinc used in galvanizing. To quote Shakespeare: "Something is rotten in Denmark."


Here's one of the simpler rope to chain splices for three strand nylon:

3-Strand Rope To Chain Splice

Joe. :teeth :thup
 
Are you wraping the chain around the bow cleat? If so--don't. You should either use a bungee cord or piece of line between the anchor shackle and the cleat. The SS and galvanized metals will interact. When you use thimbles and shackles with galvanized chain, they should be galvanized (or nylon for the thimble)--not SS. Sometimes you can get away with SS, but other times, it will cause electrolysis.

When you anchor, use a snubber (I use light 3 strand line, with a chain hook spliced to one end, and cleat the other end to the bow cleat).
 
Went digging into the anchor rode locker yesterday and found that the chain (galvanized) has a white flakey deposit on it, looks like dried salt water, and the towel in the bottom of the locker is wet. Some of the sections of chain look to be rusted. Now I am wondering:

1. What is going on, since the anchor has not been out of the locker except for twice, both times on a dock for measuring and marking? The boat is stored outside, covered and has a Sprint 600 windlass, horizontal, and a separate hausepipe.

2. What is a good treatment for the rusty galvanized chain?

3. Has anyone had any experience with this product, "EvapoRust"?

http://www.evaporust.com/evaporust.html

Thanks for your response here.

Harvey
SleepyC :moon
 
Well, when I was a kid, my mom used to put zinc oxide on my nose to keep it from burning. If I remember correctly (it was a looong time ago,) it was white. So if you're finding white stuff on your chain, I'll bet it's zinc oxide.

If the towel is wet, try to find out from where the water is coming. Also, since a chain is dragged along the bottom, run through a chain gypsy and dumped in a pile, paint isn't any good. I'd try regalvinizing.

Boris
 
Harvey,

I'd try laying that chain on the bottom for 2-3 days at a time! Swinging on the hook for a few days does wonders for the chain, the disposition, the relaxation... Pretty soon, you don't care about a little rust.
 
Boris, thanks. Funny, I don't remember Zinc oxide on my nose, but did use it on my kids for diaper rash prevention. Worked well there too. :wink

The boat has been covered and that should keep the water out of the locker from above, ( windlass or hausepipe ) but was out side at the mechanics shop for 3 weeks -- rain during then. Had a couple of instances of green water up to the bow roller last fall, but thought everything in there was dry after that. Will have to do more checking there.

Might look into the possibilities of re-galvanizing.

Still looking for in for on:

3. Has anyone had any experience with this product, "EvapoRust"?
Click to expand...
 
Unless you have a galvanizing facility nearby and have a lot of other material to be galvanized, it will be cheaper to buy new chain. (Our local galvanizer has a minimum of 300 lbs)--but many areas do not have local galvanizers because of EPA.

As for re-finishing the chain--probably the best thing to do at this point, is to use phosphoric acid to etch the chain, and convert the rust (oxide) to hard phosphate. Then spray with "cold galvanizing"--it will be much cheaper and probably last as well.
 
thataway":1zorxm7c said:
Unless you have a galvanizing facility nearby and have a lot of other material to be galvanized, it will be cheaper to buy new chain. (Our local galvanizer has a minimum of 300 lbs)--but many areas do not have local galvanizers because of EPA.

As for re-finishing the chain--probably the best thing to do at this point, is to use phosphoric acid to etch the chain, and convert the rust (oxide) to hard phosphate. Then spray with "cold galvanizing"--it will be much cheaper and probably last as well.
Click to expand...

This discussion reminds me of something I have long wondered about: what is the advantage of stainless steel for anchors and chain other than appearance?

Warren
 
Just a thought. The Cold Galvanizing I'm familiar with is a primer with (I guess suspended) zinc in it. I've tried that on the trailer and it's just like any other primer, though maybe longer lasting. Anyone know of something different?

Boris
 
The cold galvanizing is just that--a paint with zinc suspended. It will do fairly well, as long as there is no wear and is kept up. It is only a bandaid, but much cheaper and easier than re-galvanizing.

I also end for end each year the chains--on cruising boats--in that case, the most wear is at the anchor end. Again--not necessary on C Dories--as someone --see above--says many C Dories are not anchored much (ours spend more time at anchor than at docks--but may be the exception).

Incidently the initial galvanizing is only about 10 mil thick--because of the process. A good re-galvanizing-hot dip, chain racks, with shaking will give 30 to 40 mil of galvanizing coating. But the high heat may cause some loss of strength of the HT chain. Not a problem with C Dories--but can be with high load chains.
 
See how great this sight is: I am learning more "stuff" again. Lots of new research to do, Re galvanizing and cold galvanizing. Not likely to find a galvanizer in our neighborhood but will definitely start looking.

Thanks Dr Bob, Boris, Roger, Warren, DaveS, Joe and all. Looking forward to some new searching.

Harvey
SleepyC
 
Beautiful day, Been mowing the lawn, need a break (and I'm liking Roger "Dreamer's" idea of chain maintanence more and more). Now back to mowing more lawn :twisted: , Oh well, beats shoveling snow :rainbow

I also will be looking into the cold galvanizing process and availability. (Sounds more like a DIY job than the alternatives.

Harvey
SleepyC :moon
 
**** BRINGNIG BACK AN OLD (2009) THREAD *****

Last season was the first season with any serious anchoring. Most nights out of 6 weeks.

The anchor chain, (1/4" G-4 HT galvanized), did have some lightly rusty sections on it. I used a suggested cure. I found a section of gravel road that was not muddy (as if that would have made a difference) and hooked the chain to the trailer ball and dragged it for about a mile at about 5-10 MPH. That took most of the rust and whitish cover on the chain off. Brought it home and washed it thoroughly in fresh water and have used cold galvanize (rattle can) paint on the rusty sections (still in the process of several layers).

The next step is to mark the chain at several designated lengths. I'm wondering 2 things. If I paint over that cold galvanizing, will it have any adverse affect? AND, what is a good recommended paint for anchor chain?

Harvey
SleepyC :moon

IMGP2460.thumb.jpg
 
I don't know if there is such a thing as a good paint for galvanized metal.

http://www.sherwin-williams.com/homeown ... zed-metal/

Whether paint sticks to sprayed on zinc paint (cold galvanized), I don't know. Probably sticks better with less prep than hot dip, but still sounds like a pain and might not last. The problem with paint is that it will fail while just sitting in the locker.

How many markers do you need? If only a few, I'd use surveyor's tape. Tie it through chain or run it through 3 strand with a fid, leave the ends about 3 inches. Green at 50, red at 100, blue at 150, something like that. Interpolate for 125'. Simple, runs through a winch, impervious to rust, and I've had survey tape stay on for several seasons when run though the winch 50 times a year. Using one color works if you pay attention, red is 50, 100, 150. Simple. And it doesn't decompose in a damp locker.

Mark
 
When I was a liveaboard and cranked chain daily, my experience was that re- galvanizing was the only solution to rusted chain problems. If you only anchor occasionally, or don't have a windlass, then the solution can be postponed by cold galvanizing spray or other stopgap methods, but re-galvanizing or replacement is the only real solution.

Galvanizing is worn off chain where the windlass grinds against the outside of the links, but also inside the links, where they grind against each other under load. It is very hard for paint to penetrate these areas. Even so, paint won't last long in these areas because of the constant wear.

Be careful in replacing your chain. As a rookie I once bought "hot dipped" (supposedly) chain at a hardware store. It started rusting after one year. Pay the extra and buy from a commercial marine supply. As someone previously stated the coating isn't very thick, even on good chain. Re-galvanizing will triple this coating.
 
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