Larger last chain link

[model 10]

Can you use a tapered punch or drift and a big hammer to enlarge the last link in your chain? When you buy chain with an enlarged last link, how do they do it?

[Sailmonkey]

When you buy chain with a larger end link it's a longer length of wire bent an welded to form a larger link. Driving a punch through an existing link will deform and weaken the link you assault.


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[roverhi]

They weld in a large link before the chain is galvanized. These large links are quite a bit larger in a width and length than the rest of the chain, not just a standard link that's been enlarged.

[valhalla360]

No, stretching and bending metal causes "work hardening". This tends to make the metal brittle...and will often substantially weaken it.

[Sun and Moon]

Can you put a large link on an existing chain? I've been unable to find a shackle that fits my chain and matches the working load of the chain. Any shackle that fits has a lower working load.

[noelex 77]

When the chain is ordered the chain manufacturer can attach a larger link at both ends. You can subsequently ask a welder to do that for you, but the link will need to be galvanised after welding. I would also have some doubts if it will be as strong as a suitable shackle. If the welder is not very careful, the heat will destroy the tempering in the steel forming the larger link.

Unless you are using G7 chain, I am surprised you cannot find a shackle that is suitable. I presume you have looked at the most common solution, which is one of the G8 shackles from Crosby or Green Pin. I use a Crosby G-209A.

While stainless is perhaps not ideal, the Whichard HR series are also often used. They also make titanium shackles although, surprisingly, these are slightly weaker than the HR stainless version.

Hopefully somewhere in that choice of shackles there may be something that is suitable.

[barnakiel]

I have seen these on cattle chains.

On a boat, an x+1 shackle fits an x sized chain. Say 10mm chain takes 12mm shackle. Often this is enough for many applications (like mooring or anchoring).

Why do you need the oversize link?


b.

[mramoo]

Am I missing something here? Which end of the chain is the OP talking about? If it is the link that attaches to the anchor, then that link needs to be as strong or stronger than the chain. If it is the link thatches to the vessel, then it needs to be the weakest link in the chain so that in case of emergency it will break before there is any damage to the vessel.

[TeddyDiver]

Originally Posted by mramoo

Am I missing something here? Which end of the chain is the OP talking about? I

Both ends preferably.. I certainly would like to turn my chain around..

[sy_gilana]

In contrast to the above advice, yes you can, and it works. You need a "Bull Pin" it has a very gentle taper. I have 1/2" chain and a 5/8 shackle joining directly to the anchor. As you can imagine, the 5/8 shackle pin does not go through the 1/2 chain link - - just not. You must do it slowly, on mine it only took 6 smacks of the hammer. The most important thing is to enlarge it just enough to make the pin a snug fit in the last link. There should ideally be 180 degrees of contact. This will reduce wear, and spread any loads. The resulting improvement in contact area will more than exceed any 'possible' weakening of a cold post-form to a link. The caveat is that you not try to make a 1/2 " link take a 3/4" pin...now that would weaken it.

Just to set your mind at ease a little more I studied engineering in the Navy. We have been at anchor about 6000 nights now, and have sat out winds of 103 knots and more importantly large wave action. There is very little wear thanks to the 180 degrees of wrap.

Bull Pins were used by riggers doing steel work, mainly used to line-up bolt holes. Available on Amazon. The gentler the taper, the more force it will apply. One size up on the shackle is a good idea.

[mitiempo]

Originally Posted by mramoo

If it is the link that attaches to the vessel, then it needs to be the weakest link in the chain so that in case of emergency it will break before there is any damage to the vessel.

No it does not. The chain should be attached to a strong point in the locker with rope that is long enough to reach the deck pipe so if necessary it can be cut in an emergency.

[model 10]

Well a 7/16" shackle pin does fit through 5/16" G4 chain but it does not have full contact with the end of the link. I did expand the ends of the old chain with a very tapered punch and am just wondering if doing the same to my new chain is such a bad deal after all. It does not take much beating to get full contact with the pin.

[S/V Alchemy]

Originally Posted by mitiempo

No it does not. The chain should be attached to a strong point in the locker with rope that is long enough to reach the deck pipe so if necessary it can be cut in an emergency.

I just did this job aboard my boat. I did it with Dacron-covered Dyneema that is about the same strength as the 3/8" chain, but can be parted with a few swipes of a serrated knife. I keep an oiled breadknife forward for the purpose:
The world encompassed: The bitter end

In this photo are the chain/Dyneema bitter end and a second rope/chain rode for the second anchor.

[barnakiel]

Originally Posted by Guy

Well a 7/16" shackle pin does fit through 5/16" G4 chain but it does not have full contact with the end of the link. I did expand the ends of the old chain with a very tapered punch and am just wondering if doing the same to my new chain is such a bad deal after all. It does not take much beating to get full contact with the pin.

If your chain is galvanized, you may try a SS shacke too: their pin diameter is often slightly less than on a corresponding galvanized shackle ...

Cheers,
b.

[GrahamHO]

All good and interesting advice above. I'm just wondering if the anchor / chain shackle needs to have the same breaking load as the chain. I understand the chain is as strong as its weakest link etc. As I see it the chain is for weight to help the anchor and reduce the jerking loads on the vessel.. If anything is going to break it may as well be the shackle and then you still have all your chain intact to shackle on that spare anchor that is of course ready. So why not start with a shackle of suitable breaking strain and then add the chain that fits? Easy enough to change to a new shackle every year.
Just curious if anyone has had an anchor shackle or suitable chain in good condition actually break without being snagged on coral or rocks.


A relation had the substantial anchor / bowsprit on his 36' displacement power boat break when freakishly the chain must have caught on an unknown rock and the boat went up on a wave. The chain didn't break but the short anchor roller bow extension did with a crash. It is an ex charter boat built to survey and he had many years at sea in the navy. Insurance was happy to cover it.


I'm not sure of the breaking strains of various short link chains. I guess they must be more than the weight of the vessels they are used on. I imagine we could safely lift our boats on a crane with our anchor chains. ( I'm not going to try)


Being anchored in 103 knots must have been interesting and a good test!!


I'm not stating anything; just asking