Stupid questions about anchor chain

[wayneA]

At the moment I have 25 meters of anchor chain, no rode, that is handled by a Lofran ‘Royal’ manual windlass. I wish to extend this length by at least 30 meters plus another 30 meters rode.

So, my stupid questions are:

1) How do I measure the gauge of chain already on the boat – such as 5/16 etc? I don’t know what it is at the moment.

2) Can I tell if the chain is calibrated or not? If yes – How?

3) What is the best/easiest way of connecting the two chains together to give me one length?

Thanks in Advance

Wayne

 

[dickh]

Chain is measured by the diameter of the link, ¼" or 5/16" Diameter etc. but metric chain is now available, 6,7 & 8MM Diameter!
You will have to find out the exact size - and for windlasses it is usually "calibrated" so it always fits.
Not easy to join galvanised chain together and still retain the strength AND go over the windlass. Much better to buy a new length of chain the required length and sell the original.
Look at www.griffchains.co.uk - their prices are good, they deliver and you can have any length you like, probably calibrated as well - check them out.

dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[vyv_cox]

I have the same windlass. When I bought it I was advised that I needed calibrated chain, so I bought a suitable length. Later, I found that some other stuff, almost certainly not calibrated, ran through the windlass with no problems. My current warp is made up of at least three different lengths of chain, only one of which is the original calibrated piece.

I have experienced no problems with the split-type joining links.

Incidentally, if anyone from ybw is reading this, how about some destructive tests of chain, joining links, special anchor connecting swivels, anchorplait splices? Questions on these things come up very frequently and it doesn't seem like an expensive article to compile.

 

[snowleopard]

callibrated chain scam

i'm told by a manufacturer that they make all the chain the same way then run it over e.g. a lofrans gypsy and if it doesn't jam the call it 'callibrated for lofrans' and double the price. that means that if you buy this stuff you're entitled to complain if it doesn't work but any old chain of the right size will probably work.

5/16 = 8mm
3/8 = 10mm

the imperial/metric versions are usually interchangeable, try it and see.

the official way of joining chain is a split link, looks like two overlapping 'C's with a couple of rivets you hammer over, should run over the gypsy and be as strong as the rest of the chain.

 

[Jacket]

Re: callibrated chain scam

Surely a split link can't be as strong as the rest of the chain? After all, the split links are only as strong as the rivets, which by necessity have a smaller diameter than the chain links.

 

[MedMan]

The best way to join two lengths is to get a reputable welder to TIGG weld it for you. Cut the old weld out of a link, slot the two lengths of chain onto this 'joining piece' and get the welder to fill in the gap so that you have a fully-formed link that is solid all the way round. Coat it with Galvafroid paint each year and it will last as long as your chain and be just as strong.

The way NOT to do it is to make a single cut, force the gap open, link in the chain, force the gap shut and just weld around the outside of the 'join'. Joints made in this way will be very weak indeed.

 

[vyv_cox]

Re: callibrated chain scam

The rivets only hold the two halves together - there is no axial force on the rivets. The link appears to be made in a tempered, or at least stronger, steel than chain and should therefore be stronger than the chain they are joining.

 

[charles_reed]

By definition calibrated chain has links of the same size and should fit through an appropriate windlass.

It is now almost impossible to get imperial (ie 5/16") chain in the UK, unless it has been made in China for the US market or is imported from the States.

Unfortunately 5/16" and 8mm chain are not the same, the run-off means that in about 64 links you need an extra link in the 8mm to "catch up".

This is seldom a problem unless you have your chain under considerable tension when jamming can occur (the likelihood of the tension reaching this level unless the anchor has fouled, are remote).

If your windlass is of the vertical type the problem is even further reduced (you'll find vertical windlasses only have 1/4 of the circumference engaged on the chain) whereas horizontal windlasses (with 1/2 the circumference engaged) prove more of a challenge.

In most well-worn windlasses the variation in link length in uncalibrated chain does not prove a problem.
However the only way to find out is try it - none of the old imperial chain sizes are exactly the same as their metric equivalents.

Alternatively (and probably more cost- and comfort- effective) change the windlass drum - when it gets worn you'll have to in any case.

 

[Avocet]

I work for a university - in the Mechanical Engineering department. We've got lots of nice calibrated machines for pulling things (like chain and swivels) to pieces if anyone wants to do some tests!

 

[hylas]

Re: callibrated chain scam

(the official way of joining chain is a split link, looks like two overlapping 'C's with a couple of rivets you hammer over, should run over the gypsy and be as strong as the rest of the chain.)

PLEASE.. NEVER use a split link as descriebed. The breaking load is just few hundred kilos (daN) ask the manufacturer... compared with 5 000 kg for a 10 mm chain..
I will suggest that 25 m of chain is long enough.. then use a NYLON wrap and splice the nylon DIRECTLY onto the chain..
The way to do it?? have a look at: http://www.bluemoment.com/warpchainsplice.html

 

[ccscott49]

Re: callibrated chain scam

Sorry, the joining links are not as strong as a link of chain, the c pieces are trying to be bent all the time, the links are continuos, they are certainly not allowed in the oilfield for joining chains used in lifting operations only welded links are allowed, then the chain has to be retested and re-certified. Just as the pins on certified shackles are larger diameter than the shackles themselves, to put back the strength.

 

[snowleopard]

rope/chain splice

needs a special gypsy and even so easily jams in the windlass. rope tends to wear quickly, reckon on replacing every 2 years with frequent use

 

[ccscott49]

Re: callibrated chain scam

Since my last post, I've checked with the relevant authority here on the platform, these links are not certified for joining chain for lifting operations, however they are certifiable for anchor chains and general use, the consensus is that they are nearly as strong as the chain and when used on older chain are as strong. so go ahead and use them. I stand corrected.

 

[Grehan]

Thanks Hylas . .

. . thanks for that web reference. Looks clear and understandable.

Merci beaucoup aussi, for your various contributions to YBW on anchors and anchoring - they have the mark of practical and theoretical authority about them. (I do know you're somewhat "partisan")

Do you? . . . Mr Jones

 

[jfkal]

Re: callibrated chain scam

They are not. As I saw even in a chndlers catalogue it said CAUTION linj has ony 25 % of original chain strength.....

 

[vyv_cox]

Link confusion

It would be useful to have some sort of definitive statement from somebody responsible for the design or manufacture. In the past three posts we have one from a representative of an authority that says they are OK for anchor use and another from somebody else who says he has read that they have only 25% of the strength of the chain. There are more myths and false truths about this one than there are about stinkies v. raggies.

 

[dickh]

Re: Link confusion

I also understood that the 'C' type link was nowhere as strong as the original chain and to keep the strength you needed commercial 'Lifting Joining Links' which are much larger than the chain. Most authorities insist on a single length of chain for anchors.
Can a manufacturer of these links enlighten us? - with tests perhaps?

dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[Rich_F]

Re: Link confusion

Maybe the C-links are 75% weaker, but still OK for anchor chain. I would have thought that for most small craft, the important features of anchor chain are length and weight. I doubt that such anchor chains ever get anywhere near their strength limits in normal use.

 

[vyv_cox]

Re: Link confusion

I think you are right, but none of us wants to introduce a link of only 25% strength unnecessarily. I'm quite happy to use something else if necessary but unfortunately nobody seems to know the true status of these things.

 

[LadyInBed]

Re: Link confusion

Rather than a link, maybe a couple of meters of rope joining the two lengths of chain would be a better bet?