Mixing stainless & galvanised

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ash2020

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I'm making up a mooring strop, 20mm nylon 3 strand with a galvanised hard eye, then it will be bow shackle, swivel, bow shackle and on to the galvanised D ring on the buoy. How serious would it be to mix in stainless steel shackles, can't find galvanised shackles quickly enough.
 
Not terrible. Potetnial for faster corrosion with disimilar metals in salt water of course. Its the galvanised metal that'll likely wear first. So not ideal and not encouraged.
 
I once attached a galvanised anchor to a galvanised chain using a stainless steel shackle. Fairly soon afterwards the galvanising began to come off the first few links of the chain.

I replaced the s/s shackle with a galvanised one, and no more galvanising was lost from the chain.
 
I am inclined to think OP should use what he has. Being a mooring strop above water it will be easily inspected for condition. However GI shackles or SS thimbles should easy to get to reduce concern.
Now with my mooring gear I was provided by the authority with a buoywith SS swivel built in that i am obliged to use. This left SS attached to GI chain and shackles. The result was fairly short life (2 years) of shackles where they attach to SS and GI chain. wear which is normal. I got some SS chain and fitted SS shackles and this has been wear free for many years. (no GI) So it gets a mandatory professional inspection every 2 years (MOT style) but with no problems each inspection.
The moral is SS and GI don't mix well. ol'will
 
In the majority of cases mixing stainless shackles and swivels with galvanised chain has no major downsides in anchoring gear. The zinc can suffer on a few links of chain but that is usually the worst that happens.

Moorings may be a different matter as immersion in seawater is constant. Galvanic corrosion is a genuine problem here. As said, stainless components above the water may be less of a problem but the situation is best avoided
 
You omit to mention the size of your shackles - if they are small, worry.

Our mooring contractor never uses gal shackles - the gal wears off so quickly its a waste of time. Our shackles are immersed 24/7, its the seabed, silica sand, that is the killer

Its difficult to believe galvanised shackles are difficult to source in Cornwall - why not just use conventional black shackles. If you are worried about wear - use bigger shackles and monitor regularly.

Jonathan
 
Try TMS at Par.

Failing that, PM me. I'm not far away and have some new old stock/1 trip stuff here of probably about the right size? Green pin, proper dip galvanised not chinesium plate.
 
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Neeves said:
You omit to mention the size of your shackles - if they are small, worry.

Our mooring contractor never uses gal shackles - the gal wears off so quickly its a waste of time. Our shackles are immersed 24/7, its the seabed, silica sand, that is the killer

Its difficult to believe galvanised shackles are difficult to source in Cornwall - why not just use conventional black shackles. If you are worried about wear - use bigger shackles and monitor regularly.

Jonathan
Click to expand...
Thanks. They're big. 14mm pin, about 80mm across. They're not difficult to source, but I already have some v. big stainless shackles and a big galv. swivel.
 
I used a stainless shackle on a mooring penant chain while i sought a proper one. Removed it a few weeks later and was shocked by how much the steel link that the shackle was connecting had dissolved...
 
Poignard said:
I once attached a galvanised anchor to a galvanised chain using a stainless steel shackle. Fairly soon afterwards the galvanising began to come off the first few links of the chain.

I replaced the s/s shackle with a galvanised one, and no more galvanising was lost from the chain.
Click to expand...

Yup - thats how it works out in practice!
 
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