5/16 gypsy and 8mm chain mismatch?

webcraft

webcraft

Well-Known Member
Joined
8 Jul 2001
Messages
40,410
Location
Cyberspace
www.bluemoment.com
I just fitted a second hand Lofrans Royal windlass to Fairwinds. Initially chain and gypsy seemed a good match, but in real time use the chain tends to wrap round the gypsy and jam if more than 3-4 links are engaged. I haven't let it freefall yet as I am worried it might jump.

Is a 5/16 gypsy the same as an 8mm gypsy, or would an 8mm gypsy solve the problem?

- W
 
webcraft said:
I just fitted a second hand Lofrans Royal windlass to Fairwinds. Initially chain and gypsy seemed a good match, but in real time use the chain tends to wrap round the gypsy and jam if more than 3-4 links are engaged. I haven't let it freefall yet as I am worried it might jump.

Is a 5/16 gypsy the same as an 8mm gypsy, or would an 8mm gypsy solve the problem?

- W
Click to expand...
My SL windlass has an 8 mm gypsy with a 5/16 chain . It sticks exactly as you describe if I recover to fast but is fine in freefall

John
 
JVL said:
My SL windlass has an 8 mm gypsy with a 5/16 chain . It sticks exactly as you describe if I recover to fast but is fine in freefall
Click to expand...

I am not recovering fast, it is a manual windlass...

Assuming my chain is 8mm, would an 8mm gypsy solve the problem?

(Truth to tell, I have always assumed my chain is 8mm, but how can I tell the difference between 8mm chain and 5/16?)

- W
 
Yes. Some newer windlasses use gypsies that are profiled to accept both. That is what is currently listed for the Royal, but I don't know if it has always been the same.
 
RivalRedwing said:
Is the chain calibrated (or was it passing freely around the previous winch?)
Click to expand...

Both good questions, and the short answer is 'don't know'. The old windlass was knackered when we got the boat in 2003 (SL Seawolf). The free-run release worked for a few years, but eventually that stopped working as well.

I gave the old windlass to someone for repair (who didn't do it). I will try to get the old gypsy back and see if I can wrap the chain all the way round it without jamming - I cannot do this with the existing one, it jams before it is half way round - suggesting a mismatch.

- W
 
It sounds like your windlass is lacking a chain stripper - bit of metal that sticks up into the gypsy and is designed to aid the removal of the chain links form the gypsy. I don't know the particular windlass you have but it would be worth checking. You could check how it runs out by attaching a line to the anchor that stops it before it reaches the seabed. If the chain jumps when it is going out then you probably do have a problem. Your old SL windlass could probably have been revived - John at SL Spares is the master in these and any other SL items. I have an old 1989 Sea Tiger that is still working perfectly.
 
Stooriefit said:
It sounds like your windlass is lacking a chain stripper - bit of metal that sticks up into the gypsy and is designed to aid the removal of the chain links form the gypsy. I don't know the particular windlass you have but it would be worth checking. You could check how it runs out by attaching a line to the anchor that stops it before it reaches the seabed. If the chain jumps when it is going out then you probably do have a problem. Your old SL windlass could probably have been revived - John at SL Spares is the master in these and any other SL items. I have an old 1989 Sea Tiger that is still working perfectly.
Click to expand...

SL Spares wanted £600 for a new motor for the Seawolf, making it an impractical repair.

The chain stripper is not exactly in the correct position as one of the bolts sheared off, and I had to drill a new hole - but it is very close. I may take it off and try elongating one of the holes so I can move it a bit further aft, but it will only be 2 or 3 mm.

I could buy an unused Lofrans Royal on Ebay for £350, but if there is a chain/gypsy problem it would be a waste of money and time. As I understand it, if the gypsy and chain are a match it should be possible to wrap the chain all the way round the gypsy with it sitting evenly in the gaps and not jamming.


- W
 
webcraft said:
see if I can wrap the chain all the way round it without jamming - I cannot do this with the existing one, it jams before it is half way round - suggesting a mismatch.
- W
Click to expand...

That's the usual test, with gypsy off the chain should fit nicely on a complete wrap. Lofrans usually have chain size or part number cast on side of the gypsy. Compare your chain with specs on Viv's site - Chain – Cox Engineering
 
Stooriefit said:
I wouldn't agree given the amount of hassle you're describing and your idea of spending £350 on a Lofrans Royal which might not fix your problem!
Click to expand...

I would have had an ancient windlass with a non-original motor for the price i could get a new Chinese windlass of the same power.

And I didn't have £600 at the time.

And a friend said he could source a motor . . . but didn't.

- W
 
What's that old saying?

Buy cheap, buy twice?

Chinese; second hand; unknown sizes etc. It sounds that you are expecting (hoping) bits to mesh together.

Ink
 
Metric 8mm chain has a shorter link than imperial 5/16th" - they are different. The wire size is 'similar' but the links are a different length

You might be able to buy 5/16th" chain, CMP (think Rocna) make both metric and imperial chains under their Titan brand - but as virtually everyone in Europe uses metric it might be a fruitless task. There are different specifications for 5/16th" G30 is also different from BBB - but I'm not sure that matters for a gypsy.

As mentioned new gypsies cost a fortune and commonly unless the windlass is new its not worth changing - its better to buy a new windlass. But windlass do last for ever. But after, say, 20 years and no servicing I'd go the new windlass route, if the windlass is in good nick I'd certainly try too source some imperial chain. I note its a manual windlass and maybe worth searching for an old gypsy or imperial chain - but electric windlass with age - the motors start to look distinctly average. Another option for Imperial is Peerless (of America) - they, obviously make imperial and they were stocking chain in Europe - its cost nothing to send an email.



But is answer to web craft - the chain will not fit and nothing you do will allow it to fit with any confidence except buying a new gypsy or buying new chain. You might be able to fudge and worry the chain through the gypsy - but that is not the case when you are in a hurry - and it will jamb.

Apologies for not being more positive.

Jonathan
 
I thought this might be more useful.

The chain at the top of the image is Maggi A7 (now no longer available) made to a metric 8mm size specification (and all metric 8mm is made to the same size specification). The bottom chain is an American 5/16th G30, I'm not sure if its Peerless or Campbell. But all G30 x 5/16th" chain is made to the same size specification. Note - BBB is another American imperial specification, also a G30 strength, and the two sizes are different.

But note that the wire sizes for the metric and imperial chain are different, 8mm might be similar to 5/16th" but the sizes do have some allowed variation. Note also that the links a re different size - the Imperial chain is not stretched so it is actually 'longer' than it looks.

IMG_9341.jpeg


And whilst I have everyone's attention :). Americans also make as galvanised product a G43 quality (sort of similar to Metric G40) and a G70 each of these grades has a different size specification - and different to G30 and BBB. American chain makers, or some of them, also make metric chain.

Windlass makers who want to compete internationally need to produce gypsies to suit each of these specifications - and metric (noting there are 2 sizes for metric 10mm c hain). They also need to make them - and stock them. I have some sympathy for windlass makers and the cost of gypsies - its a bit of a nightmare.

Some gypsies are made to suit more than one specification - so there is some overlap.

However trying to fit 8mm chain into a 5/16th" gypsy is asking a lot.

The 'G' number is meant to reflect the strength of the wire being used to make the chain. This works quite well but note that all metric chain is made to a 4:1 safety factor, so WLL of 8mm x G40 is 1,000kg. Some American chain is made to a 3:1 safety factor which 'artificially' improves the WLL. A further complication has been that American G70 is made from a G70 quality but the heat of galvanising retempers the chain and it has a lower UTS than a 'true' G70. Metric galvanised G70 meets a G70 specification but, I'm guessing, is made from a G100 feedstock and the heat of galvanising pulls it down to a G70 quality.

I know - as clear as mud - but I am trying :)

But if you are looking at American chain, for whatever reason, start a thread before you invest any money.

Finally if you look at metric spreadsheets for chain vs vessel size - the chain quoted appears to be a G30 quality. But if you follow the guidelines you will be 'safe' - chain failure has not been quoted for years. The spreadsheets seem to be 'about right'. I recall 15 years ago chain failure was mentioned - such comments have disappeared recently. If you extrapolate you can work out what 'savings' you might make by using G40 or G70 chain based on the G30 vs vessel size spread sheets.

Take care, stay safe

Jonathan
 
Webcraft - A thought occurred to me over the weekend. I might be wrong about this but I seem to recollect that someone told me that Simpson Lawrence made their own chain which is what you may have. This was before the more recent drive to calibration and so the chain you have, although it would run fine on an SL gypsy may in fact not run alright on another manufacturer's 5/16th gypsy. If you have a look at the second page of the SL manual for the Sea Tiger (I know this isn't what you had) you'll find information on chains that were compatible with the various gypsys SL used. You can find the manual online (eg https://www.endeavourowners.com/dscsn/info/manuals/Seatiger User's Manual.pdf).
 
You must log in or register to reply here.

Share this page

Top