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Old 07-05-2016, 08:51   #1
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What size rope to what size chain?

If you have 3/8 G43 chain, what size rope do you splice to that AND get it to feed through the windlass?

Lewmar V5 quotes 3/8 with 1/2-5/8 rope. 1/2 rope is just a good snubber for any boat that needs 3/8 G43 chain, only 46% of chain strength. 5/8 is 77% of chain strength.

Maxwell RC says 3/4 rope for 3/8 chain. That is about equal.

My Lewmar V700 says 1/4 + 1/2 rope, but with a 3-strand splice that is a lie. It jams most of the time until the splice is well worn, nearly ready for replacement. Since the other V-winches take smaller rope, I'm guessing they know that.

----

Just wondering what is typical. With BBB chain this is small beans, but with G43 and even more with G70, I see a huge mismatch. Yes, Impacts loads on rope are lower, but so is the WLL/BS ratio as compared to chain.
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Old 07-05-2016, 09:06   #2
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Re: What size rope to what size chain?

It's not so much matching rope & chain, it's the strength of each as part of the SYSTEM.

Anchor System Sizing Tables (Reply #6) & Why Swivels are a bad idea Ground Tackle & Anchor System Sizing TABLES & Swivels
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Old 07-05-2016, 10:35   #3
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Re: What size rope to what size chain?

Quote:
Originally Posted by Stu Jackson View Post
It's not so much matching rope & chain, it's the strength of each as part of the SYSTEM.

Anchor System Sizing Tables (Reply #6) & Why Swivels are a bad idea Ground Tackle & Anchor System Sizing TABLES & Swivels
Well, yes, obviously.

The first post in that thread mentions 1/4 HT with 5/8" rope; that is not going to happen with a windlass and 3-strand splice, which is my point.

Other comments folks made:

Heating. While this may be important in overloaded (if the line is undersized and is working above the WLL) nylon, it is also not a factor in lines under 3/4". There is simply too much surface area fro cooling. This is a big rope problem, or short dock lines that are over loaded.

Chafe on the roller. A good case for a snubber. I used to use snubbers on rope rode just to transfer the chafe to something more disposable (an old piece of line).

Shackle sizes. Obvious. Side loading is probably the main villain. A challenge with HT chain.

Wear on splice. If the chain is short, yes, but for many they have already put out 100-200 feet of chain and the splice is probably not on the bottom. If it is, there is no weight on it (any wind at all will lift the first few links clear, which is obvious).

----

But to the point, it's hard to match rope to chain.
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Old 07-05-2016, 11:00   #4
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Re: What size rope to what size chain?

i avoid that issue by using all chain. much more security.
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Old 08-05-2016, 07:43   #5
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Re: What size rope to what size chain?

If you're using a rope/chain gypsy, you have to use the combination that fits. If you don't like the combination that fits, you've got to change the gypsy or windlass.

If you're not using a combination gypsy, you know how to do the math.

My Lewmar is designed for 1/4" G4 and 1/2" rope. I actually use stainless chain sized as G4. It's not as strong but has worked well for about twenty years.
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Old 08-05-2016, 07:59   #6
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Re: What size rope to what size chain?

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If you're using a rope/chain gypsy, you have to use the combination that fits. If you don't like the combination that fits, you've got to change the gypsy or windlass.

If you're not using a combination gypsy, you know how to do the math.

My Lewmar is designed for 1/4" G4 and 1/2" rope. I actually use stainless chain sized as G4. It's not as strong but has worked well for about twenty years.
G4 and 1/2" is a fair match, but...

But is this always true? If I want a 3/8" chain, for Lewmar and Maxwell, the gypsies are rated for 5/8" rope, which is much weaker than the chain. I cannot get a match. Or more to the point, I can't understand why they would offer a gypsy for HT chain that does not match. Please explain.

www.lewmar.com
V4 12V
Rope-chain gypsy
10mm or 3/8 chain, 16mm or 5/8" 3-strand rope.

3/8 G43 = 16200
5/8 rope = 12500

And we are not counting that rope wear faster and fatigues at lower strain. This is a mismatch and I'm not seeing a way around it.

If this had been BBB chain it would be OK. But it seems the design has not matched the times.
3/8 BBB = 11000
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Old 08-05-2016, 09:14   #7
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Re: What size rope to what size chain?

Something is wrong in your figures

10mm Maggi chain (best) is rated 6000kg breaking, 50% max stress, 25% rated use
10mm non-Maggi, European, is rated at 5000kg, that is 25% of 1250kg
An easy match for a good 14-16mm rope
Dyneema 12mm breaks at 7t
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Old 08-05-2016, 09:52   #8
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Re: What size rope to what size chain?

A windless that can handle both rope and chain through the same gypsy has to be a compromise.
A windless that handles chain, and also has a drum for the rope is the only way to be able to use the correct size rope with your chain. I have an Ideal G5 windless. I run 1" anchor rope at the end my 200 ft of G4 3/8 chain. I stop at the end of the chain, and use the drum for the rope. I do not run the splice through the chain gypsy.
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Old 08-05-2016, 10:07   #9
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Re: What size rope to what size chain?

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Something is wrong in your figures

10mm Maggi chain (best) is rated 6000kg breaking, 50% max stress, 25% rated use
10mm non-Maggi, European, is rated at 5000kg, that is 25% of 1250kg
An easy match for a good 14-16mm rope
Dyneema 12mm breaks at 7t
I don't think so. You are quoting lower grade (G30) chain, similar to the BBB I quoted, which is about the same as your number. I quoted G43, which is becoming the most common in the US.

So far I know, Dyneema is not relevant.
1. What Dynema rope will fit a combination gypsy?
2. Dynma rope floats, which presents and unaceptable prop fouling hazard.
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Old 08-05-2016, 10:10   #10
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Re: What size rope to what size chain?

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Originally Posted by MAJICDAN View Post
A windless that can handle both rope and chain through the same gypsy has to be a compromise.
A windless that handles chain, and also has a drum for the rope is the only way to be able to use the correct size rope with your chain. I have an Ideal G5 windless. I run 1" anchor rope at the end my 200 ft of G4 3/8 chain. I stop at the end of the chain, and use the drum for the rope. I do not run the splice through the chain gypsy.
I'm not sure that is true, which is the point of the thread. Perhaps with the right splice you can feed the correct rope. Or perhaps it is a matter of pressuring windlass makers to wake up to the new world of high tensile chain; there is no reason the gypsy could not have more flare to accommodate larger rope. After all, they are the ones specing G43 and G70 gypsies.
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Old 08-05-2016, 10:29   #11
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Re: What size rope to what size chain?

Thinwater, I understand your point. I'm too lazy to look it up but do the numbers work better with the metric chain and rope? It might be a gypsy designed for metric sizes that just happens to work with those inch sizes as well.

Does Lewmar make a gypsy for that windlass that accepts 3/8 G4 and 3/4 rope?

The most common rope / chain rodes I deal with are 1/4" chain / 1/2" rope, 5/16 " chain / 5/8" rope and 3/8" chain / 3/4" rope.
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Old 08-05-2016, 10:38   #12
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Re: What size rope to what size chain?

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Thinwater, I understand your point. I'm too lazy to look it up but do the numbers work better with the metric chain and rope? It might be a gypsy designed for metric sizes that just happens to work with those inch sizes as well.

Does Lewmar make a gypsy for that windlass that accepts 3/8 G4 and 3/4 rope?

The most common rope / chain rodes I deal with are 1/4" chain / 1/2" rope, 5/16 " chain / 5/8" rope and 3/8" chain / 3/4" rope.
I'm pretty sure this is how Lewmars are sized. We have the Lewmar V1 & it takes 5/16 chain & 5/8" line.
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Old 08-05-2016, 12:02   #13
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Re: What size rope to what size chain?

16mm Octoplait to 8mm G70
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Old 08-05-2016, 14:23   #14
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Re: What size rope to what size chain?

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I'm pretty sure this is how Lewmars are sized. We have the Lewmar V1 & it takes 5/16 chain & 5/8" line.
Yes, that makes OK sense, but the V4 still says 5/8 rope at 3/8 chain. Odd. However, it does not allow for the more rapid wear of rope and the lower WLL (the WLL limit on rope is about half that of chain).

And if folks go to G70 it will be a mismatch.
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Old 08-05-2016, 15:38   #15
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Re: What size rope to what size chain?

I took a look at the gypsys available for the V4/5 Lewmars and Thinwater is right, none of them make sense to me. No shortage of other good windlasses on the market.

As for G70 chain, I don't think it's suitable for use in a combination rode. You'd have to go to one of the new high tech fibers to get the strength in a reasonable size. I'm sure it could be done but it's just not cost effective for most people. Maybe for a racer trying to save every pound.
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