ISO chain and BS EN calibration question. Confused? Very

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Cathy*

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My head is spinning.

We've splashed out on a new Rocna 15kg anchor and want to add to our chain. From the Lewmar website the chain we need is 10mm ISO, Campbell 3/8" S3, Lewmar 9.5mm G40. Looking at very useful coxengineering website it seems that we need chain calibrated to ISO 4565

I have found measurements for 10 links to double check that we do have ISO and not DIN which we will be doing next week. In the meantime we've been researching suppliers.

The best price we can find is for :-

10mm Hot dipped Galvanised to ISO 1461 Welded short link 30mm X 15mm internal measurement Calibrated to BS EN 818-3 Grade 40 High test carbon steel.

Does this sound like the same chain?
 
That sounds strange to me.

10mm chain is either short link 28mm internal or long link 30mm internal.

Your find says short link 30mm which sounds like a contradiction so I would definitely give them a call before ordering.

Richard

Apparently 28mm and 30mm are both called "short link" so my inference above is not correct.
 
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At the 10mm size the DIN and ISO standards have different dimensions, by 2mm of pitch, although they are both short link chain. ISO4565 is 10x30x14 but DIN766 is 10x28x14. At other sizes - 6mm, 8mm, 12mm both standards have the same dimensions.

BS EN 818-3 is G4 calibrated short link chain, at 10mm its dimensions are 10x30x15. It has a higher SWL than ISO/DIN.
 
Salty John said:
At the 10mm size the DIN and ISO standards have different dimensions, by 2mm of pitch, although they are both short link chain. ISO4565 is 10x30x14 but DIN766 is 10x28x14. At other sizes - 6mm, 8mm, 12mm both standards have the same dimensions.

BS EN 818-3 is G4 calibrated short link chain, at 10mm its dimensions are 10x30x15. It has a higher SWL than ISO/DIN.
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Thank you that's very informative. So that chain would probably not be suitable then?
 
I have a 25KG Rocna and 10mm chain. If your boat is OK with a 15KG Rocna it should also be OK with 8mm chain. If you change the windlass gypsy and buy 8mm chain you can get more chain for less weight, and little more cost even after buying the new gypsy.
 
If you can I would cut 3 or 4 links off your existing chain and take it with you when you purchase. That way you can compare what you have with what is on offer.

I did not understand your opening post as it suggests they you can use Campbell imperial 3/8th" (S3?) and Lewmar 9.5mm G40. These 2 chains read to be very different dimensions to me - though confess I have never seen, knowingly, Lewmar 9.5mm.


I have to ask - why has the purchase of a new anchor prompted the purchase of more chain? Much depends on what you have already but the idea of swapping to 8mm has great merit, 10mm G40 sound overweight and overly strong for a 15kg anchor. But gypsies are expensive. Smaller chain means less volume, less risk of towering under the windlass, cheaper and, of course less weight. 8mm would be more than strong enough for a 15kg anchor and will be less of a burden to your windlass (or you if you ever need to retrieve by hand).

Jonathan
 
Norman_E said:
I have a 25KG Rocna and 10mm chain. If your boat is OK with a 15KG Rocna it should also be OK with 8mm chain. If you change the windlass gypsy and buy 8mm chain you can get more chain for less weight, and little more cost even after buying the new gypsy.
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The physics of anchoring is a bit more complex than that Norman. Much of the restriction of movement and shock absorbing relies not on the anchor itself but on the weight of the chain and its catenary. So it can make sense to put a heavier chain on an existing anchor. If you ever get to the point where your chain is bar tight and the anchor is not moving then the component first to fail will be the cleat / deck fitting anyway.

But turning to the issue in question, the din and iso standards are different at 10mm for some reason. I would have thought it likely that the OP would have been supplied Din chain. He needs to check the pitch which will be 30mm for ISO and 28mm for DIN.
 
Birdseye said:
The physics of anchoring is a bit more complex than that Norman. Much of the restriction of movement and shock absorbing relies not on the anchor itself but on the weight of the chain and its catenary. So it can make sense to put a heavier chain on an existing anchor. If you ever get to the point where your chain is bar tight and the anchor is not moving then the component first to fail will be the cleat / deck fitting anyway.
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Here we go again?
 
Fascinating - this is a 2016 thread. I would have hoped Cathy the OP has solved the problem by now. But if they use their chain daily - they should be due new chain by now.

In the intervening years we have thrashed to death catenary, chain size and snubbers.

Amazing.
 
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