Thickness of chain?

[NickC]

Anyone care to guess what thickness this chain looks like? See links below:
P1000951.JPG
P1000952.JPG
P1000954.JPG
P1000955.JPG

It was supposedly new and has been on the seabed for one year and three months.

 

[sarabande]

a bit like Schrodingers's cat then, both new and used ?


From the shoe laces, I'd guess it's 15mm bar, +/- 2mm.



If you post a pic with something better for scale, e.g. box of matches, biro, credit card, etc, we could give a more accurate estimate.

 

[Stork_III]

1"

 

[NickC]

What I am trying to establish is what thickness the chain was when it was laid 1 year 3 months ago, supposedly new.

The shoe is 11.5cm wide for reference.

There is a shackle in the middle of the second pic P1000952.JPG this has WLL21 written on it is that a known standard size shackle, does that give us any size reference.

 

[VicS]

my estimate based on a comparison with the trainer is nearer 20mm. 3/4" perhaps if its Imperial

 

[alahol2]

I make it 1.9 cm AKA 3/4"

 

[sarabande]

trust VicS

Now we have some data: on my screen, the shoe measures 26mm, and the chain 5mm. If the shoe is 115 broad, then the chain is 22mm. Very roughly, parallax and corrosion notwithstanding.

 

[Stork_III]

What I am trying to establish is what thickness the chain was when it was laid 1 year 3 months ago, supposedly new.The shoe is 11.5cm wide for reference.There is a shackle in the middle of the second pic P1000952.JPG this has WLL21 written on it is that a known standard size shackle, does that give us any size reference.

WLL21 is Working Load Limit 21 tons, usually 1 1/4"

 

[CreakyDecks]

The links look the same size as my 16mm ground chain.

 

[Searush]

Anyone care to guess what thickness this chain looks like? See links below:
P1000951.JPG
P1000952.JPG
P1000954.JPG
P1000955.JPG

It was supposedly new and has been on the seabed for one year and three months.

This may be a silly question, but have you tried measuring it? You simply measure the diameter of the bar it is made of.

 

[Amulet]

This may be a silly question, but have you tried measuring it? You simply measure the diameter of the bar it is made of.

Agreed. I often find that measuring things is quite a good way to work out what size they are. Put the calipers on it. http://www.screwfix.com/p/forge-steel-vernier-calliper/38291 You need a caliper like this anyway if you don't have one. There are zillions of things which have to be measured where it is the only useful tool. Cheaper plastic ones are available and probably adequate for your task.

 

[NickC]

Didn't have calipers with me the day I took the pics and it has now been moved so I can't measure it.

 

[NickC]

As only been in the water for just over a year should we have expected to still see some paint on the chain?

Has anyone got a similar WLL21 'D' shackle to measure the diameter of the bar.

 

[sarabande]

shackle working loads will vary according to the 'strength' and quality of the metal from which they are made.


For instance, a Crosby shackle with a WLL of 2 tonnnes has a pin diameter of 12.7mm. It's made from alloy steel.

A Contact shackle, made from less tough steel, has a pin diameter of 16mm, for the same WLL.



It is a variable feast.

 

[NickC]

It has now been pointed out that the shackle actually says WLL2T not WLL21 as previously assumed.

The other question is how long would you expect the paint on new chain to last, after just over a year would we not expect to find some paint still left on the chain?

This actual chain was supposed to be brand new 22mm when the mooring was laid just over a year ago. Does that look likely?

 

[Searush]

It has now been pointed out that the shackle actually says WLL2T not WLL21 as previously assumed.

The other question is how long would you expect the paint on new chain to last, after just over a year would we not expect to find some paint still left on the chain?

This actual chain was supposed to be brand new 22mm when the mooring was laid just over a year ago. Does that look likely?

So much depends on the nature of the mooring ground.

Some locations eat chain because the fine sand grinds it away & highly oxygenated salt water can corrode it very quickly. Other places, the chain sinks into the mud & is preserved in an anaerobic layer that never moves, so the initial oxidation layer forms & then stabilises. You really need to chat to other mooring owners nearby.

 

[NickC]

Bit of an update to this situation.

The boatyard now claim that my new chain is not within the trot layed out in the pictures. It is supposedly still on the sea bed as apparently it was necessary to leave one end of the trot in place as an end marker. That doesn't quite add-up as the new chain should have been on the opposite end of the trot to that which has been left in the water.

There are a total of five moorings on this trot. If we take a look at the following picture:
P1000958.jpg
It shows all five risers attached to this old second-hand chain, not four as would be expected with one spare ready to be attached to the new chain supposedly still on the sea bed.

 

[William_H]

The chain size will be what is now measured at the sides of each link. Chain wears at the pressure points between 2 links and not on the sides. The obvious rust will actually make the chain appear a little bigger than it is. The paint or galvanising has gone if it ever was there from friction with the bottom when moving.
It appears that OP has an argument with the yard. So good luck with that. olewill

 

[johnphilip]

Looks wrong to me

I have not had to work with ground chains since we were moored on half tide moorings on the Severn. But for my penny worth...
Two points occur to me. Firstly, in the mud filled soup that the chains used to lie in it was wear at the end of the links due to this grinding paste that could destroy the links amazingly quickly rather than corrosion.
Secondly by having only rope risers with no chain the ground chain will be dragged around constantly speeding the above. With a chain riser before the rope strop the ground chain is dragged about far less. We used to regard the risers as much more easily replaced sacrificial components.

I see no reason to use new for ground chain, better to spend the money on the heaviest secondhand available.

 

[johnphilip]

Come on the metallurgists out there, is the extent of the corrosion due to the type of steel. Is it a higher carbon steel that will corrode more easily?