Anchor chain corroding after 2 years

[Terry Cox]

Cruising in the PNW.

Took a picture today of our ACCO brand hot dipped galvanized 5/16" chain purchased in 2015. Anchored hundreds of times since. Fresh water rinse after each cruise, some lasting a month or so. The Crosby swivel shackle is also USA made and hot dipped galvanized.

 

[skunther]

Took a picture today of our ACCO brand hot dipped galvanized 5/16" chain purchased in 2015. Anchored hundreds of times since. Fresh water rinse after each cruise, some lasting a month or so. The Crosby swivel shackle is also USA made and hot dipped galvanized.

View attachment 238072View attachment 238073

That looks like mine after 2 years.

 

[skunther]

Where is your anchor locker drain located? On my boat it is at the lowest point of the locker so all water drains out and my chain never sits in any water. I do have a plastic panel it sits on that allows a small airspace and way for water to drain easily under the chain.

Rinsing with Salt Away is not a bad idea it you can also rise it well afterwards. Too much work for me on my boat but you may have a method that is less labor intensive. A fresh water rinse is also not a bad idea. I don't do either. But my chain stays pretty dry in my anchor locker.

Checking for errant current you need to check two aspects - your wiring: connections and insulation; and your motor: windings and internal connections although these are done in one step really.

dj

Drain is at the lowest point of locker. There is also a molded dam with a drain slot just aft of where the chain lives (see pic). Not sure if putting plastic drain mats (like Dry-Dek) would provide any benefit. I’d do it if so.

 

[thinwater]

Drain is at the lowest point of locker. There is also a molded dam with a drain slot just aft of where the chain lives (see pic). Not sure if putting plastic drain mats (like Dry-Dek) would provide any benefit. I’d do it if so.

And water drives seawater into the locker every time you sail? Seems odd that the drain was not baffled, or better yet, put on the side and farther aft. A design oops for certain, and potentially at the root of the problem. You should have posted this first!

 

[skunther]

I don’t think that’s it… drain hole sits ~3.5’ above the waterline, and I rinse thoroughly with fresh water after every sail.

 

[thinwater]

I don’t think that’s it… drain hole sits ~3.5’ above the waterline, and I rinse thoroughly with fresh water after every sail.

I would not assume. The simple answer is to go sailing in 10-20 knots hard on the weather, and then walk to the bow and look. Is there water in the locker? Simply resolved by observation. Done. (If I opened the locker on my F-24 under those conditions, it would soon fill from the top!)

If that is a 35' boat, then that hole is no more than 2' above the water. I am sure water slides up the bow that far, smashing through waves, if there is any wind and seaway at all. A flat section on the stem, like that, will cause water to climb rather than part. Easy. I'd also bet folding money that some of the salt is reaching the rope part of the rode, which is hard to rinse out.

You rinse the chain locker every time, anchor or no? Wow. It's good to remove the superficial salt, but that also guarantees everything is wet. And like most boats, rainwater drains around the hatch and through the locker, which is good and bad.

I'd add a baffle. My drain is well aft, and now that I think about it, I'm going to add a small clamshell. My last boat had one there.

 

[dLj]

And water drives seawater into the locker every time you sail? Seems odd that the drain was not baffled, or better yet, put on the side and farther aft. A design oops for certain, and potentially at the root of the problem. You should have posted this first!

Just as a note, years ago (not my current boat) had an anchor locker/drain very similar to that one in that picture - my anchor locker got a lot of water in it from the drain hole even though it was at about the same height out of the water. And by a lot of water, it would fill my anchor locker.

dj

 

[skunther]

We don’t day sail much, so 95% of the time we take the boat out, we anchor. We’re in the Salish sea, sail with our two young daughters and really don’t sail in any weather over 20kts. Right now, close hauled and at 18kts apparent, the hole is pretty well clear of the water and splashing. I checked the locker and it’s pretty packed in there, and I just pulled anchor this morning, so it’s a hard gauge whether much water is getting in. Maybe some is getting in, but salt water already gets in every time I pull anchor (i have no wash down). Either way, as I rinse after each sail (longest we’re out without a rinse is maybe 2 weeks), wouldn’t any saltwater ingress be irrelevant? Rain certainly gets into the locker, but doesn’t the drain and opening at the drum create enough circulation to evaporate the rain enough for it not to be an issue?

Is my situation so markedly different from others who are getting 10+ years from their chain? I

 

[colemj]

It appears that you have decided the chain has a lot of corrosion. It doesn't look that way to me - in fact, it looks about what I would expect for a 2yr old chain with moderate use. Your pictures look like those of @Terry Cox . While he states his is 10yr old, he didn't state whether the minor rust where links touch, along with spot rust only occurred after 10yrs, or has been steady like that since year 2.

One difference is that his chain looks from his pictures to be just a short shot of chain backed up by mostly rope. As such, it probably isn't going through a windlass gypsy and tumbling onto itself and grinding inside the locker as yours likely is. Those processes can chip galvanizing, and cause more linkage contact wear.

But, to me, your chain looks fine.

Mark

 

[thinwater]

Does chain ever pile as far forward as the forestay fitting? That is a ground, but I don't staining.

Just searching for ideas.

 

[Terry Cox]

As such, it probably isn't going through a windlass gypsy and tumbling onto itself and grinding inside the locker as yours likely is.

Hi Mark. Yes, the picture does show a bit of minor rust where some of the links touch. That pile of chain its 50' and I always use the gypsy to bring it in, paying it off by hand.

 

[skunther]

It appears that you have decided the chain has a lot of corrosion. It doesn't look that way to me - in fact, it looks about what I would expect for a 2yr old chain with moderate use. Your pictures look like those of @Terry Cox . While he states his is 10yr old, he didn't state whether the minor rust where links touch, along with spot rust only occurred after 10yrs, or has been steady like that since year 2.

One difference is that his chain looks from his pictures to be just a short shot of chain backed up by mostly rope. As such, it probably isn't going through a windlass gypsy and tumbling onto itself and grinding inside the locker as yours likely is. Those processes can chip galvanizing, and cause more linkage contact wear.

But, to me, your chain looks fine.

Mark

I noticed corrosion on my chain, which surprised me, and I created this post to ascertain if the amount of corrosion I’m seeing is normal or not as I don’t have enough experience to know.

 

[skunther]

Does chain ever pile as far forward as the forestay fitting? That is a ground, but I don't staining.

Just searching for ideas.

It doesn’t touch the forestay hardware.

Is stray current a likely concern? How exactly would I check this? I don’t fully understand the circuit. Is it more of an issue with the chain deployed? Stored?

When stored, the chain and locker drain pretty well and I rinse it as I mentioned. Rainwater would definitely get in the locker, but is that a factor in a stray current scenario?

One thing - I do leave the windlass breaker on. I don’t know if that could be a factor in causing corrosion or not.

I did just install some drainage panels at the base of the locker to help with drainage and aeration, so hopefully that helps some too

 

[thinwater]

It doesn’t touch the forestay hardware.

Is stray current a likely concern? How exactly would I check this? I don’t fully understand the circuit. Is it more of an issue with the chain deployed? Stored?

When stored, the chain and locker drain pretty well and I rinse it as I mentioned. Rainwater would definitely get in the locker, but is that a factor in a stray current scenario?

One thing - I do leave the windlass breaker on. I don’t know if that could be a factor in causing corrosion or not.

I did just install some drainage panels at the base of the locker to help with drainage and aeration, so hopefully that helps some too

I really was not thinking stray current pre se.

If the chain is grounded when deployed (the forestay and rigging are certainly grounded somewhere for lightening), then the zinc on the chain becomes sacrificial, like any of the many annodes on the hull protecting the prop, shaft, thru-hulls, and connected piping from corrosion. Does this make sense? The coating is thin, so it does not last very long.

I have witnessed (dock mate) a chain destroyed in a few months by a fault in the windlass. Probably not your case, since the damage was localized to just a few feet.

Another possibility is that the chain is somehow connected to the ground in the locker. None of these seem to be true.

• Touching forestay mounting plate hardware. You say no.
• Water draining to the bilge, which is grounded. The drain is external.
• Any other grounded hardware. I didn't see any, but it's occasionally a problem. Once I saw a chain fixed at the bitter end to a u-bolt that was through-bolted to outside the bow in the splash zone. A ground.
• Windlass. Most (all?) winches are ungrounded for this reason. The breaker position should not make a difference, since it is on the same side (hot) as the switch.

All I can suggest is looking for possible ground paths for the chain.

I've have always had catamarans, so the chain locker was no where near the forestay, or really, any hardware other than the windlass. My trimaran has no windlass, and the locker is several feet away from the forestay and drains overboard. No ground, just a fiberglass tub. However, I do have corrosion, because the locker is constantly wet (rainwater, rope, and not enough ventilation).

 

[skunther]

Would the simplest method to check if the chain is grounded be to check for continuity between the chain and the forestay?

 

[thinwater]

Would the simplest method to check if the chain is grounded be to check for continuity between the chain and the forestay?

Sure.

The ground may (probably) is intermittent, so you will have to check at the marina, anchored, and underway, probably at least twice each.

But yes, that will either point to the problem or confirm it isn't the problem.