Lofrans Cayman 88 chain size

James W

James W

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Evening all,

I need to order some new anchor chain and the measurements on the old chain are a little odd (45mm OD, 25mm ID, 10mm diameter).
BGD tell me that if I take the windlass gypsy to them, they can run the chain through it to make sure we get the right size, but I don’t have the time to take two trips to Ipswich because they then will need a couple of days to plait the rode onto the chain, before I can pick it all up again.

The gypsy has 3/8 HT stamped on it, which suggests it’s a 10mm gypsy (the chain diameter bears that out). Does anyone else have a Cayman 88 windlass and could advise me on the size of 10mm chain they have please?

Thanks so much, James
 
I had a 3/8" gypsy on a Lofrans Kobra. Worked really well until I had the chain galvanised. After that the chain (thirty years old or so) jammed in the gypsy every time it was raised.

Eventually bit the bullet and bought new 8mm Lofrans chain and the right gypsy and stripper for the boat.

I still have 50+ metres of the chain which is near as dammit your spec above in quite good nick.

Ink
 
Good Morning James

The 10mm and 3/8th" sizing of chain is nominal. I believe a 7% size variation is permitted.

I confess that I've stuck to looking at 5/16th" and 8mm chain for my chain surveys as its cheaper, lighter and easier to break - otherwise I'd go and measure what I have.

For imperial chain sizing look here:

Welded Chain Specifications

For metric chain sizing go to Vyv Cox's website (Google to find it).

I assume your chain will be a G30, note that imperial chains comes as a G30, G43, G70 and BBB grade and each grade has a slightly different links size (its a real can of worms). American chain is meant to be marked, on every few links its grade, size and there is commonly a code for the manufacturer. Chinese chain is generally unmarked (I don't know what happened in the UK when chain was made locally). Here PWB and Serafini both mark their chain.

10mm is superficially similar to 3/8th" but 3/8th" chain is imperial and different to 10mm metric. Some gypsies are forgiving and will accept imperial and metric. I would contact Lofrans direct and ask them what exactly the 3/8th" means, ie is it an exclusive imperial designation. If it is specifically for imperial chain I think you are wasting your time trying to find a metric match (but strange things do happen). Most (I suspect, all) windlass makers have a spread sheet of gypsies and designate which gypsies match specific chains. These spread sheets can be on the their websites but are difficult to find - but their distributor/agant in the UK should have easy access to the spread sheets.

Any good chandler can accept your gypsy and run chain through it though whether many local chandlers carry imperial chain in the UK seems very unlikely. If you take your gypsy you can do it yourself - its not difficult. CMP Titan (of Rocna fame) make both imperial and metric chain and if you work with one of their chain distributors might be you best chance. I simply don't know but if you need to order in imperial chain that might be expensive and it might be cheaper to simply buy a new gypsy (or new windlass if this one is possibly getting a little old and tired).

If you follow the new gypsy or windlass option - you then have opportunity to look at buying an 8mm gypsy or windlass (if your 10mm is a bit oversize) and the savings on buying the smaller chain might make the purchase of a new windlass, slightly, less painful. I only say this as there does appear to be a consistent use of chain heavier than necessary on many yachts (especially those where weight is important to engender decent performance).


My first enquiry would be to Lofrans but you could contact the nearest local Lofrans distributor/agent at the same time.

Jonathan
 
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These are (some of) the gypsies made by Lofrans, there is one marked for both 3/8 and 10mm ISO
[630994] GYPSY KOBRA/CAYMAN/TIGRES/ROYAL 8mmISO4565/DIN766 #276C
[631077] LOFRANS GYPSY KOBRA/CAYMAN/TIGRES/ROYAL Ø5/16 HT#276D
[631011] GYPSY KOBRA/CAYMAN/TIGRES/ROYAL 10mmISO-3/8 HT #276E
[631118] LOFRANS GYPSY KOBRA/CAYMAN/TIGRES/ROYAL 10mmDIN766 #276F
[631120] LOFRANS GYPSY KOBRA/CAYMAN/TIGRES/ROYAL 3/8 BBB #276G
[631122] LOFRANS GYPSY KOBRA/CAYMAN/TIGRES/ROYAL 3/8 PC #276H

You may double check your chain size here 10mm DIN ISO chain
 
This is a wealth of information, thanks everyone! I think there’s more research needed and if that proves inconclusive, the gypsy will have to come off!
 
James W said:
This is a wealth of information, thanks everyone! I think there’s more research needed and if that proves inconclusive, the gypsy will have to come off!
Click to expand...

Following on from Neeves suggestion of changing to 8mm chain, i think this is worth looking into. Lofrans make a range of gypsies for the Cayman, mine is 8mm. A decent grade of 8mm chain should be fine for your boat (post details and i'm sure Jonathan will confirm). It wouldn't be a bad thing to get some weight out of the bow and the difference in price between 10mmand 8mm chain will absorb some of the cost of a new gypsy, according to the Jimmy Green website an 8mm gypsy is £179 and 8mm chain is £3 per metre cheaper than 10mm, so you break even with 60m of chain.
 
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Neeves said:
My first enquiry would be to Lofrans but you could contact the nearest local Lofrans distributor/agent at the same time.

Jonathan
Click to expand...

I should have maybe said or contact Roberto, well done!



James

Note there are a number of varieties of 3/8th gypsy, an HT which I think is High Test or G43, BBB which is an old standard - but still used and chain is still sold, and PC (not sure what that one is!)

You have found the 3/8th" mark - there might be another mark, HT or BBB and even better the number, that Roberto lists. You can then cross reference to the 10mm metric - again note some of the 3/8th" don't have a metric equivalent.

With metric chain its easy, apart from 10mm where there are 2 sizes but metric 8mm chain of whatever quality G30 or G70 - the links are the same size.

Peerless, America's biggest chain maker is now part of the Japanese company Kito and they have a warehouse in Germany. If you find you actually need an Imperial (sometimes called 'English' :) ) chain contact Peerless, in America, and mark the email 'International' and they might stock what you need, the other option is CMP with the Titan range. OR follow Paul's research.

I'd be wary of G43 - it looks much better than it actually is because they use a 3:1 safety factor (all metric and some Imperial use a 4:1 safety factor) so the WLL looks fantastic - if you check the MBS you will find it better reflects reality.


To me chain standards, specifically American) are a nest of snakes - but it is what it is. This is not anti American - its not much better in Oz and NZ where we have our own standards, G30 is called Grade L (and is slightly different to metric G30 - beggars belief). We don't have a standard for the Crosby G209a shackle - so they are not used for lifting (even though they are twice as good as 'our' standard) so they are unpopular and cost a fortune. Its cheaper to buy them from the UK than buy locally - bizarre.

Jonathan
 
Neeves said:
You have found the 3/8th" mark - there might be another mark, HT or BBB and even better the number, that Roberto lists. You can then cross reference to the 10mm metric - again note some of the 3/8th" don't have a metric equivalent.
Click to expand...

He says HT in post #1 Jonathan
 
PaulRainbow said:
If my memory is correct, James has a circa 41ft French production yacht.
Click to expand...

If you memory is to be trusted (and I have no reason doubt you, at all :) then I would seriously look at 8mm G40 (and a new gypsy - or if the windlass is tired - a new windlass (with a 8mm gypsy). The advantage of the 8mm chain, it takes up less room, it removes weight from the bow, if towering is an issue the more room should offer a better 'fall' and reduce towering. 10mm weighs 2.3kg/m and 8mm 1.45kg/m.

8mm will demand a new gypsy and you should be able to get a new gypsy to fit the existing windlass.

But windlass should last forever, or decades - so the need for a new windlass ought to be unlikely.

I have seen, on new yachts at boat shows, windlass installed with the fall of the chain rubbing the motor, or less awful the motor doused with water every time it is used. Many windlass are abused and the seals fail - resulting in the gearbox being lubricated with mud and salt water. Though they are abused and ignored they are very simple and amazingly robust - they should be serviced annually - its really not difficult.

Jonathan

James, my post crossed with yours :). Now - you might be able to do a deal - if the chandler throws in a new gypsy - you'll buy from him but 8mm chain. If you don't ask you don't know and a raised eyebrow and a 'No' costs you nothing!

Take care, stay safe.

J
 
Than
Neeves said:
If you memory is to be trusted (and I have no reason doubt you, at all :) then I would seriously look at 8mm G40 (and a new gypsy - or if the windlass is tired - a new windlass (with a 8mm gypsy). The advantage of the 8mm chain, it takes up less room, it removes weight from the bow, if towering is an issue the more room should offer a better 'fall' and reduce towering. 10mm weighs 2.3kg/m and 8mm 1.45kg/m.

8mm will demand a new gypsy and you should be able to get a new gypsy to fit the existing windlass.

But windlass should last forever, or decades - so the need for a new windlass ought to be unlikely.

I have seen, on new yachts at boat shows, windlass installed with the fall of the chain rubbing the motor, or less awful the motor doused with water every time it is used. Many windlass are abused and the seals fail - resulting in the gearbox being lubricated with mud and salt water. Though they are abused and ignored they are very simple and amazingly robust - they should be serviced annually - its really not difficult.

Jonathan

James, my post crossed with yours :). Now - you might be able to do a deal - if the chandler throws in a new gypsy - you'll buy from him but 8mm chain. If you don't ask you don't know and a raised eyebrow and a 'No' costs you nothing!

Take care, stay safe.

J
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Thanks Jonathan, you’ve been a great help.
I’ve just been talking to a chain supplier and they tried to talk me out of 8mm, pushing towards 10mm. What do you think? I’d be happy to go down the 8mm route, but would be concerned at the strength on a boat that might reach 12 + tonnes fully loaded.

Thanks again, James
 
You are not going to lift the yacht using the chain!

8mm G40 has a min break strength of 4,000kg and should be higher. The WLL of G40 8mm chain is 1,000kg and for 10mm - 1,250kg. My estimate is (based on actually testing our cat) you are unlikely to have a tension in your rode in excess of 500kg, ever (your wife will have called the divorce lawyers long before you achieve that tension!) I would suggest you use a decent snubber and it will absorb the snatch loads.

Go and check with, say, Lewmar, at their recommendation for chain size.

Think back of posts in this forum. Some in this forum have a yacht the same size as yours, or bigger, and some will use 8mm chain. When was the last time you read of a chain failure, or a stretched chain? Do you recall reading posts of people who complained their chain was too small, wished they had bigger chain - and went off and bought bigger. People want more chain - but not bigger chain.

Note: I'm not a great believer in catenary and in carrying extra weight, many others disagree with me (in this very forum!). Catenary is good to around 30 knots - and then just when you need it - your chain is as straight as an, old, billiard cue. You can deploy more chain - but maybe there is not room - but a snubber offers an ability to extend the ability of your rode. So if a snubber offers an effective way to replace catenary - why carry the extra weight anyway.

But I have said all this many times - and been criticised for being repetitive.

Jonathan
 
FWIW I have a similar boat to yours, I thought about going the 8mm G70 chain road but eventually decided to stick to 10mm. Ugly truth, my boat loses about half a knot with the 70m chain at the bow (checked against my shorter 25m chain cable).
My main reason for keeping the 10mm is rate of corrosion, after some comparison I reckon I can squeeze a couple more years with 10mm chain before having to replace it, I have noticed 8mm HT wears faster in boats with similar use (simple observation, not sure if it can be generalized but it's what I have seen in a few real cases and what I prefer to decide upon).
Other reason, all the anchoring parafernalia I have like chain hooks, claws, shackles, connectors etc are made of higher grade metal (G70+) and their physical dimensions match very well the 10mm chain; a friend with 8mm G70 chain wanted for some reason a specific type of shackle and connector and could not find one with acceptable breaking load which would fit with his chain. Besides, I already have all that equipment -well tested too- I am happy with so laziness prevails :)
I personally would not use 8mm regular steel chain, I have stretched (slight permanent deformation) some of my 10mm chain, I am not willing to risk a similar treatment with 8mm G30-G40 chain; to tell the whole truth I do not want to risk it again full stop :D

James W said:
I’ve just been talking to a chain supplier and they tried to talk me out of 8mm, pushing towards 10mm. What do you think? I’d be happy to go down the 8mm route, but would be concerned at the strength on a boat that might reach 12 + tonnes fully loaded.
Click to expand...
 
Hi James - I've got hold of a new Tigres for our Voyage and stuck with the 10mm ISO. I just used Jimmy Green's instructions for measuring 10 links of chain to match the size. I haven't fitted the new one yet, nor tested the chain on the gypsy, what with Wales lockdown.

I don't have anything like the technical knowledge shared above and the main reason for going 10mm was that, with the hit of the cost of the windlass, I didn't want to replace the chain too straight away. Hopefully it won't be a drama to source 10mm ISO when the time comes? But I don't think I'd have gone down to 8mm. We're hoping to take the boat as far as SE Asia so lots of anchoring in store if we can pull it off. 10mm fits nicely in the locker and it just hadn't occurred to me to go down a size.

As you'll probably have seen, replacement gypsies are pricey so you that's another factor.
 
Roberto said:
FWIW I have a similar boat to yours, I thought about going the 8mm G70 chain road but eventually decided to stick to 10mm. Ugly truth, my boat loses about half a knot with the 70m chain at the bow (checked against my shorter 25m chain cable).
My main reason for keeping the 10mm is rate of corrosion, after some comparison I reckon I can squeeze a couple more years with 10mm chain before having to replace it, I have noticed 8mm HT wears faster in boats with similar use (simple observation, not sure if it can be generalized but it's what I have seen in a few real cases and what I prefer to decide upon).
Other reason, all the anchoring parafernalia I have like chain hooks, claws, shackles, connectors etc are made of higher grade metal (G70+) and their physical dimensions match very well the 10mm chain; a friend with 8mm G70 chain wanted for some reason a specific type of shackle and connector and could not find one with acceptable breaking load which would fit with his chain. Besides, I already have all that equipment -well tested too- I am happy with so laziness prevails :)
I personally would not use 8mm regular steel chain, I have stretched (slight permanent deformation) some of my 10mm chain, I am not willing to risk a similar treatment with 8mm G30-G40 chain; to tell the whole truth I do not want to risk it again full stop :D
Click to expand...

To stretch chain you need to develop a tension 2 times the WLL OR have chain that is, well, out of specification. To stretch a commonplace 8mm G30 chain would need a tension of 1.5 tons and for G40 chain 2 tons. Excused me if I say these tensions are very unlikely. However I have tested chain that stretched at much less than Proof Load (2 x WLL). Chain is Proof Tested, or should be Proof Tested as a continuous process during manufacture, that's 2 x WLL and basically should not stretch permanently at those tensions. The tensions I quote are huge - you will break something else first - or drag your anchor! At those tensions your snubber should fail, or your snubber is too strong. You will damage the bow roller (on a modern AWB) etc etc.

Finding components that match G70 chain is a major issue. Why companies manufacture a product, in this case G70 chain, without offering easy access to the essential components that you need to match the chain is a complete mystery.

If you wanted a mixed rode you cannot splice rope to a G70 chain with the rope a bit stronger than the chain, because the rope is too big (unless you were to use dyneema). You can have enlarged links added to the chain when you order it - but if you keep the chain for any length of time those end links corrode preferentially - and then what do you do! Crosby shackles are only as strong as a G40 chain (if the shackle is loaded at 90 degrees) for which the clevis pin fits. You can use hammerlocks or omega links - but they are not, or very seldom, galvanised - so they go rusty and need to be treated as consumables. The best chain hooks are from the lifting industry - again not galvanised. You could use a soft shackle instead of a chain hook - but it is very difficult to thread the soft shackle through the smaller link of the G70.

You can overcome all of this - we had excess components galvanised when we galvanised our chain - but most people would be looking to buy the chain off the shelf - so this option is not available. The only route I can think of is find someone having their chain regalvanised and add you components to the batch.

I've run tests and small chain with same quality of galvanising wears at the same rate as large chain. The big issue is not that small chain wears faster but that the quality and thickness of the galvanising varies. People don't use small chain because they say the chain is not on the seabed to the same length of time as large chain - if its not on the seabed - how does it abrade? Abrasion is weight, or mass vs surface area and time in contact with the abrasive medium.

I've been mentioning, interminably (I'm told) - but I've now made (or managed) 4 high tensile rodes and I specify a coating thickness of a minimum of 100 microns (the US Navy with the similar chains and the same process specific 80 microns). You will find no chain maker specifies galvanised coating thickness specification, no chain maker measures galvanising thickness and quotes it to the public - but coating thickness is directly proportional to abrasion rate (even the industry says so). Equipment to measure coating thickness is common place, cheap and the measurement is also quick (and easy). I obviously have a coating thickness meter - and hope all galvanisers also have them :) but evidence suggest - they don't bother (the customer does not ask(

Jonathan

Some people have complained about galvanising life, saying its too short, that their G70 chain has abraded most quickly than a lower 'G' number larger chain, that a specific manufacturer's galvanising is rubbish etc etc.

I did a very crude back of envelope comparison and calculation of galvanising coating chain life for people who used their chain for a definable period - they either were liveaboards or they used their yachts for a decent and regular length of time. I posted my calculation on YBW, but simply don't recall what the thread was. The answer was a life of about 4 years is about right. But even this is a bit meaningless as a liveaboard who spends all their time at anchor with the occasional move to a new close by anchorage will use their chain more than someone who is moving longer distance across the Carribean or round the world - so 4 years is a very movable feast.

But there was surprising consistency - all my answers, it was not a very big envelope, were 4 years.

Chain coating thickness should be 70 microns - losing 70 microns over 4 years is - amazing. - its 20 microns a year,, 1,5 microns a month - methinks expectations are too high.

If you anchor in mud - the galvanising will be 'eaten' by the sulphur compounds in the mud (more quickly than the chain will be abraded). Sand based on calcium shell with be less abrasive that silica sand - so many variables.

I did my own tests using a cross section of chains, 12mm to 6mm - abrasion rates for the same thickness of coating do not depend on chain size, but are related to coating thickness. Blaming the manufacture might be correct but without better quantification is simply trolling.

J
 
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