Anchor stained black

[Pmcsurf1]

We're on the loop and use our 55 lb Mantus anchor almost daily. Anchor has changes colors a few times over the last year but this last time it came up black. Only parts under the mud or sand was black. The top of the roll bar was normal galvanized color.
We've used the anchor a couple dozen times after and it's still stained. Any chemist out there know what happened?

 

[GoneFarrell]

One possible explanation is that you anchored in mud with sulfate reducing bacteria, nasty smelly stuff, and that lead to a reaction with the zinc coating in the mud. Or a bottom layer of anaerobic bacteria, low oxygen environment. No way to know what bottom mud chemistry is without sampling.

Try splashing/scrubbing some CLR on the anchor, see if it cleans it up a bit.

 

[Pmcsurf1]

Good idea. Don't mind the color. Black looks kinda cool. Thanks for the reply. Sulfates. Who'da thunk it

 

[DavidM]

Don't use too much CLR or similar or for too long. These react with the galvanizing and will slowly dissolve it.

David

 

[Alaskan Sea-Duction]

Not to be stuffy about it.

Its an anchor!!

It isn't a chrome want-to-be anchor that you polish.......

 

[Mako]

If aesthetics are important, then after an wash, hit it with etching primer (since it's galvanized) and then 2-part epoxy paint. Advantage that I found is that it helps to shed mud easier.

 

[Nomad Willy]

Powder coat or a lesser finish.
I use cold galvanize spray on many of my anchors that I modify. May need to do it several times a year tho. Just haul it off on the dock w a pice of cardboard, aim and shoot.

And there are many other finishes.
Lots of options. Even colors.

 

[Pmcsurf1]

I was curious about the color change. I would not paint the anchor. It is not a show boat. We live aboard and use the anchor daily.

 

[O C Diver]

Sometimes there can be contaminants in the mud from heavy industry. I anchored in Ludington harbor off Lake Michigan while on the Loop. The anchor and chain that went into the mud, came up badly stained. Not to hard to surmise what might have caused that.



Ted

 

[slowgoesit]

If it really concerns you, give Mantus a call and see what they say . . .

 

[RT Firefly]

Greetings,
Mr. Pm. As others have posted, some sort of chemical reaction involving zinc (galvanizing). https://en.wikipedia.org/wiki/Galvanization. Might also be a reaction with the underlying steel anchor. The galvanizing may be wearing thin as you mentioned daily usage.

I wish I could help more but Chem 101 was over 50 years ago...Memory follicles are getting a bit grey.

 

[Alaskan Sea-Duction]

I was curious about the color change. I would not paint the anchor. It is not a show boat. We live aboard and use the anchor daily.

What he said!!

Mine turned this color this past summer while in saltwater.