Protecting galvanized steel anchor

[GarthGregory]

Why even debate the issue !- just re-galvanize the anchor

[Sofie B]

Originally Posted by GarthGregory

Why even debate the issue !- just re-galvanize the anchor

I agree. For protection for yourself and boat if nothing else. Common sense.

[JPA Cate]

Plus, there comes a time with the pins on CQRs that they need a bit of re-building. When the pin becomes too worn, the plow cannot assume the proper position for digging in. Repair is possible, with re-galv to follow, and then will be good for many, many anchorings, before it needs re-done. For those who want more peace of mind, get a new generation anchor.

Ann

[Philip St1]

I still think a zinc bolted to the anchor would help protect any more noble metal in the water like it does for anything else. It has been pooh poohed here on the forums here, though. Why wouldn't it work for any anchor? (other that when it breaks off on a rock?)

[Paul L]

Originally Posted by Philip St1

I still think a zinc bolted to the anchor would help protect any more noble metal in the water like it does for anything else. It has been pooh poohed here on the forums here, though. Why wouldn't it work for any anchor? (other that when it breaks off on a rock?)

It won't work because the the loss of galvanization is due to mechanical erosion from scraping on rocks, coral and sand. If you look at where the galvanization is missing on an anchor that gets used often, it is on the edges and points.

[Paul L]

Originally Posted by GarthGregory

Why even debate the issue !- just re-galvanize the anchor

Is it really worth the money to re-galvanize an old relatively small CQR anchor, when there are so many better anchors available at not that much more than re-galvanizing (unless perhaps you can get it thrown in with someone elses bigger job).

[Paul L]

I just painted my Spade with Por-15 rust preventative and a two-part top coat.. We'll see how long it lasts this season.

[Philip St1]

Originally Posted by Paul L

It won't work because the the loss of galvanization is due to mechanical erosion from scraping on rocks, coral and sand. If you look at where the galvanization is missing on an anchor that gets used often, it is on the edges and points.

Dear Paul L

The usual parts of a boat that a zinc protects are bare metal, too. I am thinking of the propeller shaft, through hulls, and the like. Yes, the zinc on an anchor comes off where it is scraped, but a proper zinc anode on the shaft of the anchor might provide some protection---would it not---like it does for the above??

Galvanizing is a thin coating and doesn't behave like a properly grounded zinc on a hull does, at least that is what my engineering/material science background is telling me.

[Jim Cate]

Originally Posted by Philip St1

Dear Paul L

The usual parts of a boat that a zinc protects are bare metal, too. I am thinking of the propeller shaft, through hulls, and the like. Yes, the zinc on an anchor comes off where it is scraped, but a proper zinc anode on the shaft of the anchor might provide some protection---would it not---like it does for the above??

Galvanizing is a thin coating and doesn't behave like a properly grounded zinc on a hull does, at least that is what my engineering/material science background is telling me.

The rust t hat appears on bare spots on an anchor does not occur whilst the anchor is in the water, but rather when it is at rest on the bow in an oxygen rich atmosphere. Adding an anode will not do a damn bit of good to prevent this. A totally different situation than protecting submerged metal parts.

Jim

[wsmurdoch]

Originally Posted by Jim Cate

The rust that appears on bare spots on an anchor does not occur whilst the anchor is in the water, but rather when it is at rest on the bow in an oxygen rich atmosphere. Adding an anode will not do a damn bit of good to prevent this. A totally different situation than protecting submerged metal parts.

Yes, and in addition, under water, the little electrons moving in the metal and the ions moving in the water will find the galvanizing zinc both closer to the bleeding iron and of greatly larger surface area than the much smaller and more distant bolted on zinc anode. The bolted on anode will have little beneficial effect.

[Snowpetrel]

An interesting thing about painting a galvanised fitting is that it can concentrate all the loss of the anode (the galvanising in this case) onto any exposed galvanising like where the paint has been chipped off. So overall it may result in less protection and premature failure as the thin galvanising gets quickly eaten away in just a few locations. Rather than slowly eroded over the whole area.

On a painted anchor a separate replacable anode might be worthwhile, if it is sitting underwater for long periods of time. I wonder if an aluminium anode would work better?

But anyway as mentioned the galv tends to wear away mechanically in key places before it fails overall as an anode.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app