Chaining from 8 to 10mm chain on electic windlass

[Paddydog`1]

Hi all,
I have a Lofrans Airon electric windlass with a drum taking 8 mm chain. I want to upgrade to 10mm chain. How do I do that?

 

[KellysEye]

Just change the winch gypsy to the larger size. I assume the hole in the deck is big enought to take it also the anchor locker has to be big enough.

 

[vyv_cox]

First check that the manufacturer makes a gypsy to fit that particular model. In many cases going up a chain size means many other changes, to motor, gearbox and static parts. My Maxwell for 8 mm is not the same as the 10 mm version.

 

[Pleiades]

If you can identify the model number of your Airon check the spec against the tables shown on the Lofrans website under "Chain management" - you may find that the same windlass is used for models covering 8 to 10 mm chain -the only difference being the gypsy on the top.
I had a slightly different objective in that I wanted to go from 3/8 inch chain to the (slightly larger) 10mm chain. I wanted to replace with much longer length of 10mm chain (120 meters - could not find that length of 3/8th and didn't want a link.) I contacted Lofrans and they said "try it and see if it works - should be ok".
Result - works perfectly - no need to change the gypsy.
Hope you get it sorted.

Robin
Pleiades of Birdham
MXWQ5

 

[Neeves]

Why do you want to change from 8mm to 10mm?

If its a fear of weakness of the chain, why not simply buy a better 8mm. If you go to 10mm, you will have a weight penalty in your bow increased from 1.4kg/m to 2.0kg/m, the locker will be more full (and the chain will 'tower' higher more quickly) - when you could have, maybe, thought of buying longer chain. If you want better 'holding' why not buy a better anchor (you can always retire the first anchor as a back up (which you cannot do with the retired 8mm chain - unless you are to deploy by hand). Buying 10mm chain and a gypsy (and at the least you will need a new gypsy), looks expensive and there may be other options - achieving the same thing, depends on the reasoning.

Jonathan

Jonathan

 

[GrahamM376]

I don't know if Lofrans are back in production yet after Navimo went bust but, even before that, it took 3 months for our new gypsy to arrive. Also, make sure to order either DIN or ISO depending on which you need, as the chain pitch is different.

 

[John Barry]

Why do you want to change from 8mm to 10mm?

If its a fear of weakness of the chain, why not simply buy a better 8mm. If you go to 10mm, you will have a weight penalty in your bow increased from 1.4kg/m to 2.0kg/m, the locker will be more full (and the chain will 'tower' higher more quickly) - when you could have, maybe, thought of buying longer chain. If you want better 'holding' why not buy a better anchor (you can always retire the first anchor as a back up (which you cannot do with the retired 8mm chain - unless you are to deploy by hand). Buying 10mm chain and a gypsy (and at the least you will need a new gypsy), looks expensive and there may be other options - achieving the same thing, depends on the reasoning.

Jonathan

Jonathan

There's doesn't have to be a weight penalty.

Using your figures 50m of 8mm chain and 35m or 10mm chain both mass 70kg (weight will be slightly less in water, and I think that your 10mm chain mass is a bit low).

With a 5m height 50m of 8mm chain will be lifted by a horizontal 346kgf.
35mm of 10mm chain and 15m of warp will be lifted by a horizontal 453kgf.

With a 10m height 50m of 8mm chain will be lifted by a horizointal 157kgf.
35m of 10mm chain and 15m or warp will be lifted by a horizontal 224kgf.

In both cases (and in all other similar cases) it takes more 'pull' to lift the same weight of heavier chain for the same rode length and the same depth, although of course there may be handling problems with larger chain.
(The increased horizontal forces required to lift the rode given above represent about 15% and 20% more wind respectively)

The length and size of chain is always a compromise, but more weight in the rode and more weight lower down in the rode do make a difference to how the rode behaves.


John

 

[noelex]

Why do you want to change from 8mm to 10mm?

If its a fear of weakness of the chain, why not simply buy a better 8mm.

This sould be a much better solution. New gypsies are quite expensive.
I have not checked the tables, but G7 8mm should be as strong as G3, or even G4 10mm even allowing a bit for the reduced snatch load performance.

I got some Italian Magi G7 chain for a reasonable price a couple of years ago, but don't believe their quoted delivery time.

If you do decide to go with 10mm be careful matching the gypsy to the chain. Their are two metric standard specifications (and 3/8 as well)
Some gypsies will only work with one or the other.

 

[Neeves]

There's doesn't have to be a weight penalty.

Using your figures 50m of 8mm chain and 35m or 10mm chain both mass 70kg (weight will be slightly less in water, and I think that your 10mm chain mass is a bit low).

With a 5m height 50m of 8mm chain will be lifted by a horizontal 346kgf.
35mm of 10mm chain and 15m of warp will be lifted by a horizontal 453kgf.

With a 10m height 50m of 8mm chain will be lifted by a horizointal 157kgf.
35m of 10mm chain and 15m or warp will be lifted by a horizontal 224kgf.

In both cases (and in all other similar cases) it takes more 'pull' to lift the same weight of heavier chain for the same rode length and the same depth, although of course there may be handling problems with larger chain.
(The increased horizontal forces required to lift the rode given above represent about 15% and 20% more wind respectively)

The length and size of chain is always a compromise, but more weight in the rode and more weight lower down in the rode do make a difference to how the rode behaves.


John

I tend to forget we live in the Lucky Country, where coral (or rock) is common and we need to carry an all chain rode. We cannot carry nylon here, coral eats it overnight. Consequently the luxury of a 35m x 10mm of chain + nylon is simply not part of the equation.

5m height, say here in NSW is not an issue (with 2m tides), but up in mid Queensland, simply not possible with 10m tides and in fact not possible in Bass Strait with even a 3m tide as at 5m with a 2m draft and a bow roller, say 1.5m above sealevel, we would actually need anchor in minimums of 7m (so subtract, 1.5m bow roller, 3m for tide and 2m draft we would have 0.5m under the keel - to me questionable) and at 8 or 10:1 to cater for some interesting weather we now need a minimum of 60m or 70m of 10mm chain, which at 2.35kg per m (more acceptable?) is 152kg vs 91kg of 8mm G7 and we can balance that lack of catenary with some decent snubbers (which will continue to work upto the breaking point of 2t) and in the OPs case not need a new gypsy.

Jonathan

 

[vyv_cox]

If you do decide to go with 10mm be careful matching the gypsy to the chain. Their are two metric standard specifications (and 3/8 as well)
Some gypsies will only work with one or the other.

There is a new page on chain materials and sizing on my website, under Anchoring. All the specifications in one place.