Anodes on a mooring

sailbadthesinner

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I fear the moorings have been put down without anodes
Can i attach them anywhere or send them down on an an angel?
Any advice please.
It s going to be tricky to get a diver
Is it a case of no choice but to lift and re-lay
its about 9m of water at HWS
The mooring bases are steel flat plates with an eye in sand.
can't remember the chain but its looking a bit more worn than i expect.
The boats are 16 ft speedboat wioth outboard and MK11 silhouette or, if someone buys the silhouette, a lugger or shrimper
A chap who has dived down there in the past reckons the bottom is like an old scrap yard so probably lots of glavanic potential.
My prefered option is to attach anodes but not sure how.
Many thanks
 

jerryat

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AFAIK it's not usual to place anodes on mooring chain. Having said that, several of us in our club do bolt our old, used anodes to our riser chain to eke out the rest of their life usefully. Easily done each year when our (swinging) moorings are checked by the club.

As an aside, despite my initial scepticism, I am very impressed with the 'all stainless chain' moorings a couple of the guys have installed. After at least three years there's not a sign of any wear or corrosion. Am now thinking of saving up lots of pennies and going the same way myself.
 

William_H

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I have never seen anyone fit an anode to a mooring chain. Certainly (I havn't in 23 years of maintaining my own mooring.
However chain will wear. it is not electrolytic corrosion but just plain rust which is accelerated by the constant wearing away of what should be a protective rust layer between the links.
I would reckon on my moorring a 3/8 inch chain (link metal diameter) would last about 1 season before I would be concerned by the wear. ie down to half. And that is with a fairly small boat on it.

Metal does seem to dissapear more quickly where iron is onto stainless steel. Perhaps that is some sort of electrolytic action of different metals.

If you go for all stainless steel you need to overspec because it is liable to unexpected failure. There is a name for it, crevis corrosion I think. Many people wouild advise against it. I am not sure.

Our local mooring authority issued buoys which we are obliged to use. They include a stainless steel rod through the buoy with a swivel built in. Of the 3 thousand or so in use after about 7 years some have failed in the stainless steel but an awefull lot of people still rely on the 10mm SS rod betwen the boat and the mooring. (not me I bypass the SS with a rope from under the buoy.

So all I can suggest is that you buy your own scuba tank and do your own in water maintenance. (like I do) olewill
Yes you do need training on the scuba use.
 

sailbadthesinner

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Right thanks for thatt
the plate is too big to replicate in stainless
the riser chain seems to be wearing quicker than i expected and someone else mentioned they had anodes on their chain. I had never fitted them before.

The scuba would be useful actually. but i don't fancy doing my padi at stoney cove and anyway it would have to be 2 as my wife ( who loves diving) would have to buddy me just in case.
and so thats 2 padi courses in the sun
plus all the gear incl dry suites

for that i could get a bigger boat
which would make my worries worse /forums/images/graemlins/shocked.gif

aaargh /forums/images/graemlins/blush.gif
 

jerryat

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[ QUOTE ]
I have never seen anyone fit an anode to a mooring chain. Certainly (I havn't in 23 years of maintaining my own mooring.
However chain will wear. it is not electrolytic corrosion but just plain rust which is accelerated by the constant wearing away of what should be a protective rust layer between the links.
I would reckon on my moorring a 3/8 inch chain (link metal diameter) would last about 1 season before I would be concerned by the wear. ie down to half. And that is with a fairly small boat on it.

Metal does seem to dissapear more quickly where iron is onto stainless steel. Perhaps that is some sort of electrolytic action of different metals.

If you go for all stainless steel you need to overspec because it is liable to unexpected failure. There is a name for it, crevis corrosion I think. Many people wouild advise against it. I am not sure.

Our local mooring authority issued buoys which we are obliged to use. They include a stainless steel rod through the buoy with a swivel built in. Of the 3 thousand or so in use after about 7 years some have failed in the stainless steel but an awefull lot of people still rely on the 10mm SS rod betwen the boat and the mooring. (not me I bypass the SS with a rope from under the buoy.

So all I can suggest is that you buy your own scuba tank and do your own in water maintenance. (like I do) olewill
Yes you do need training on the scuba use.

[/ QUOTE ]

You may not have seen anodes on chain before, but as there is no other obvious use for well-eroded anodes, it seems to us a perfectly reasonable use.

With regard the chain, our club requires 3/4" chain from the main ferry chain set in the concrete sinkers to the mooring buoy (though this size is slightly reduced for the drying moorings) and this size only needs to be changed about every 5-10 years in my experience here (28 years).

The s/s chain by the way, has a metal thickness of 5/8", so although lighter than the normal stuff, is still pretty heavy IMHO. Not cheap, but we got a good deal locally by buying bulk.

I don't agree with you re the greater wear/corrosion with s/s onto mild steel chain. It was precisely this concern that stopped me grabbing some of the club's s/s chain before it all went! However, as I said earlier, to my great surprise, when we checked the moorings a few weeks ago, there wasn't the slightest sign of a greater degree of corrosion in any of the these situations. True, some have only been thus connected for three years, but that's still pretty impessive IMHO.

Oh, do agree with you about the s/s rod type - wouldn't entertain one for my boat!
 

William_H

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Hello Jerryat of course we are talking impressions and preferences here so differing opinions is hardly surprising.
A 3/4 inch chain is pretty heavy and yes it would last perhaps 10 times as long as a 3/8 chain.

The stainless to iron wear that I havee observed is where all the wear is on the iron the SS seems oK. That is where the iron shackle is fitted to the bottom of these confounded buoys. Incidentally the rotten things are too heavy to hoist aboard the bow so they get very fouled with weed and they bump and damage the gel coat.
Mooring s used to be free and uncontrolled then controlled then they bought in a licence fee. To soften the licence fee the buoys were provided. Licence fee is 100 squid PA. But the sight is owned so they are rapidly appreciating in value. Around 800 to an amazing 2000 squid. So it is nice to ahve some real estate value appreciaion.

To sailbadthesinner I would say that diveiing with a partner is bad news. You spend more time worrying about the partner than doing the job.
good luck olewill
 

ccscott49

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Stainless wont make the steel rust, but will degrade the zinc, once the zinc has gone, the mild steeel will just rust anyway. Anodes on the chain? Well I suppose you could, makes some use of old ones. In your case max, I'd just get a bigger chain, if galvanised, use old anodes on it, but it's wear and tear I reckon, thats wearing it away, that and good old rust!
 

jerryat

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[ QUOTE ]
Stainless wont make the steel rust, but will degrade the zinc, once the zinc has gone, the mild steeel will just rust anyway. Anodes on the chain? Well I suppose you could, makes some use of old ones. In your case max, I'd just get a bigger chain, if galvanised, use old anodes on it, but it's wear and tear I reckon, thats wearing it away, that and good old rust!

[/ QUOTE ]

Yes of course you are right, good old rust and wear will get you every time. Some of us here bolt the old anodes onto the chain in the (probably vain!) hope that corrosion will be at least delayed a bit!

Mind you, I seem to recall that you could buy chunks of mooring chain a few years ago that had a bl**dy great chunk of zinc moulded round one of the links. I wonder if they're still available?
 
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