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Thread: Stainless steel chain ?

  1. #1
    Join Date
    Apr 2007
    Location
    Caribbean cliff edge
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    14,167

    Question Stainless steel chain ?

    For over a decade I have been using stainless steel chain



    attached to an aluminum 'Fortress' anchor with a stainless steel D shackle



    then to 3/4" three strand nylon rope to anchor and moor my 22'0"centre console Mako.

    The boat is anchored in Caribbean salt water for months at a time. Anchor hauled up and rebedded each time boat is used.

    So far have found no fault with set u
    p.

    Although the stainless steel chain is more expensive (initially) would have had to replace galvanized chain in that period.

    However somebody mentioned that
    stainless steel chain can suffer from fatigue and cavity corrosion(?) and is not really safe?

    What are your views.
    Enjoy a good rum on the rocks at sunset.

  2. #2
    Join Date
    Feb 2000
    Location
    San Francisco Bay
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    11,247

    Default Re: Stainless steel chain ?

    Cavity corrosion should not occur if the chain is brought up now and again. While it's quite nice looking, I certainly don't think the price justifies it for anchor rode purposes and who sees it when it's on the bottom? A proper length of steel chain, hot dipped galvanized, should last a very long time before showing any rust and needing another "dip," which is not an expensive proposition if you have a bunch to have done. (It's usually charged by the pound of pieces to be dipped.) Hot dipped galvanized chain is not the stuff Home Depot sells. If you've got stainless and it isn't showing any damage, then dance with the girl you brought.

  3. #3
    Join Date
    Apr 2007
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    Caribbean cliff edge
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    Default Re: Stainless steel chain ?

    The hot dip (not the electro - which are worse) rust chains here like crazy. Plus there aren't any facilities to 're-dip' here or close by.
    Enjoy a good rum on the rocks at sunset.

  4. #4
    Join Date
    Jun 2010
    Location
    PNW, an island west of Seattle
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    1,171

    Default Re: Stainless steel chain ?

    Practical Sailor did an article about stainless chain a few years ago:
    https://www.practical-sailor.com/blog/-10926-1.html

    Jeff

  5. #5
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
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    33,337

    Default Re: Stainless steel chain ?

    Trouble with stainless is that a visual inspection, no matter how thorough, will not identify crevice corrosion nor fatigue cracks.
    It really is quite difficult to build an ugly wooden boat.

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  6. #6
    Join Date
    Jul 2011
    Location
    Lindstrom, MN
    Posts
    1,635

    Default Re: Stainless steel chain ?

    The type of corrosion to worry about on an anchor chain is pitting. The pitting is much more of a problem with stagnant water than moving water. If it was pitting, you would see signs of rust.

    A stainless chain on a mooring that sits still enough on the bottom long enough to become fouled will suffer from crevice corrosion as a result of fouling, but one that is moved often enough should not. The water in contact with the chain on a sand bottom will be far more aerated than on a mud bottom, and aerated water keeps stainless stainless. You might see more corrosion if you store the wet chain in a plastic bucket for weeks at a time.

    As long as there isn't much tension on the chain most of the time, the contact resistance between links will make it hard to develop enough galvanic current to cause trouble. I would not be surprised to find that you find a very high contact resistance between the aluminum anchor, which will have an oxidized surface and the shackle. The lack of corrosion evident on the anchor is a good indication that it is making poor electrical contact with the chain.

    Fatigue takes a fairly high load and a large number of load cycles. If you yank the chain hard a few hundred thousand times, fatigue would be a consideration, not that any other metal wouldn't do the same thing. The aluminum anchor is much more likely to fatigue than the chain.

    Crevice corrosion occurs where there is a tight contact between the stainless steel and another surface. To run the test, flat stainless surfaces are bolted to plastic cylinders with notches around the end and soaked in salt water. http://corrosion-doctors.org/Forms-crevice/ASTMG78.htm

    Each notch forms a crevice and the corrosion develops at those locations.
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