Anchor chain specs.

emandvee44

emandvee44

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I am in the process of purchasing some new chain to extend the 50m I already have.
The gypsy on my windlass (Lofrans Tigres) is marked


(Diameter symbol) 10 P. 30

3/8 H.T.


Does anyone know which chain spec is correct, DIN 766 or ISO 818 ?

Note that I measured the chain links with a digital caliper and the inside length of a link is 30mm, and outside 50mm, material diameter 10mm.

Cheers,

Michael.
 
it looks as if DIN766 & ISO4565 are very very close,

http://www.williamhackett.co.uk/products/chain-products/bulk-chain/calibrated-anchor-chain

and it seems that ISO818 (Hi-test) is 2mm longer per link.

http://www.cruisersforum.com/forums/f118/chains-under-different-standards-13111.html

( see GMac's post.)


EDIT

Some confirmation of the size difference.

http://www.erikdeman.de/html/sail016d.htm

See Note 1 under the cross-section diagram and size table.

At present I can't find a reliable technical reference, though.

EDIT2

And Lofrans say that you need different gypsies for DIN and ISO.

http://www.svb.de/index.php?cl=details&anid=809&lang=1&aufruf=html


EDIT3

DIN 766 has an internal length of 28mm

http://www.svb.de/index.php?cl=details&anid=809&lang=1&aufruf=html

Other spec tables agree, and give a +/- of 0.5mm tolerance.


It seems the internal length is the key.

EDIT4 :)

It seems the stamp no (part no) for a 10mm ISO gypsy is 10103. Can you see that on the gypsy ?
 
Last edited:
There is a strange anomaly with 10 mm chain. In all other sizes of interest to us DIN 766 and ISO 4565 dimensions are the same. For 10 mm the link length for DIN is 28 mm and for ISO it is 30 mm. The internal width in both cases is 14 mm and wire diameter 10 mm.

However, American High Test (Ht) 3/8 inch has a link length of 31 mm. The internal width is 15 mm. Note that American Grade 30 (Proof) dimensions differ from those of HT.

Is it possible that your existing chain is USA made?
 
I also have a note in my anchor chain file to the effect that Lofrans windlasses will not take DIN chain in that size - need 30mm internal length.
 
Anchor chain size

Thanks to all for your research and replies and valuable links:rolleyes:

The windlass on our boat is original, as is the chain (afaik), and the yacht, as you all know, is a Bavaria. It seems unlikely that the chain would be American.

Based on all the information to hand, I have concluded that the gypsy markings mean:-

chain diameter 10mm P. 30 = pitch 30mm ie inside length of a link?

3/8" H.T. means the gypsy can also accept 3/8" (9.53mm) High Test chain.

Note that there is some tolerance in what these gypsies can handle, and I suppose 0.5mm is within that.

Therefore I have a gypsy which requires ISO 818 spec. chain.

Yesterday I measured several links and they were all spot on, no difference measurable between links even with the digital calipers.

Interestingly, a friend with a yacht in the same yard has found a problem regarding mis-match. His anchor chain had been extended sometime before his recent purchase of the yacht, and when he was recovering the chain on board a few days ago, all went well until he reached the 'new' chain section, shortly after which the new chain jumped off the gypsy and ran out onto the ground. He measured the two chain sections and sure enough found them to be significantly different, 10mm chain, but one DIN & one ISO.

I hope this thread will prove useful to many others out there who are extending their length;)

Regarding the Crosby joining links, even though these are of slightly different dimensions to a 10mm (or 8mm) calibrated chain link, these will pass over the gypsy without causing a 'jump'.

The actual dimensions of a (10mm. 3/8") Crosby link are as shown in the images below.

Thanks again all of you,

Michael.
 
emandvee44 said:
I hope this thread will prove useful to many others out there who are extending their length;)

Regarding the Crosby joining links, even though these are of slightly different dimensions to a 10mm (or 8mm) calibrated chain link, these will pass over the gypsy without causing a 'jump'.
Click to expand...

I will be putting the info I have on my website when I get around to it. I recently spent a lot of time researching chain for a YM article that will be in the next issue. I didn't have Salty John's useful windlass info but fortunately it confirms what I understood :)

Crosby C-links are to a different standard, not actually being being intended for marine chain, but I confirm that they will pass most gypsies. My old chain had two C-links in it, one with a length of just under the chain link length but the other was about 1.25 times the length of the chain links. It never bothered the windlass in the slightest.
 
emandvee44 said:
3/8" H.T. means the gypsy can also accept 3/8" (9.53mm) High Test chain.

Note that there is some tolerance in what these gypsies can handle, and I suppose 0.5mm is within that.

Michael.
Click to expand...

Note that American chain is 1/32" bigger than the nominal size. 3/8" American chain is actually 13/32" or 0.406", 10.3mm.
 
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