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Old 27-04-2016, 19:15   #76
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Re: Chain Stopper Installation Questions

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Exactly, if the snubber survives hurricane conditions, then it does not do it's job during "normal" conditions. It must stretch to absorb the shocks and this stretch is what does the internal chafing. If you go up in size, or change to Dyneema, then it may not break during a hurricane but it also doesn't do it's shock absorbing in 20-25 knots of wind.

Yup. Which is exactly why I have a dyneema strop holding a chain hook to a bow cleat for a backup. My everyday snubber should be fine up to 35-40. I have a storm snubber for more, but wouldn't have enough stretch for normal conditions.

In my opinion, the need for a bulletproof chain stop is for the unexpected squall, etc- like the Bahamas derecho just written up in CW. A normal snubber has high chance of breaking, and you need something to hold the chain when it does until you can rig a secondary.
And a chain stopper can't be released under load, but my dyneema strop can be cut under load once the new snubber is rigged. I also trust cleats mounted near rail where glass is solid and stronger than wimpy chain stop mounted in middle of cored section of foredeck.

All above in theory so far for me, as I've never had a snubber failure. But when we go further in a few years, much more real possibility.


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Old 28-04-2016, 05:57   #77
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Re: Chain Stopper Installation Questions

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Yup. Which is exactly why I have a dyneema strop holding a chain hook to a bow cleat for a backup. My everyday snubber should be fine up to 35-40. I have a storm snubber for more, but wouldn't have enough stretch for normal conditions.

In my opinion, the need for a bulletproof chain stop is for the unexpected squall, etc- like the Bahamas derecho just written up in CW. A normal snubber has high chance of breaking, and you need something to hold the chain when it does until you can rig a secondary.
And a chain stopper can't be released under load, but my dyneema strop can be cut under load once the new snubber is rigged. I also trust cleats mounted near rail where glass is solid and stronger than wimpy chain stop mounted in middle of cored section of foredeck.
I like the chain stopper. I don't have one as it would be really hard to install one onto my boat.

There should be enough moments even in a nasty gale between the swings to power the boat forwards when pointing straight into wind so you can winch up the chain.

My windlass has a pretty puny pull compared to the force of windage on the boat in a gale/storm of about 1.8 tons. It will be overpowered by windage over about 35kts. The boat will have to be strongly powered forwards to give it a chance of working at all. (I do power forwards usually, just to protect the windlass in anything over a gentle breeze).

If you need to get the chain up and can't take the load off the windlass so as to allow it to wind up the chain then there is no point cutting the dyneema strop. Unless:

In hurricane or near hurricane strength winds and where you just can't get the anchor up and you believe it safer to get rid of your anchor and run for it out to sea is perhaps the only scenario where a chain stopper might be a liability and a strop or heavy duty snubber is preferred. You will have a harder job to free the chain from the stopper than with a strop - you will have to pull the chain back with another winch or two or something to flick it up and allow the chain to run out. If the wind is up to hurricane strength you probably won't be able to do it. There are some stoppers with pull out pins to allow an emergency release, but I wonder if they would work in extremis?
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Old 28-04-2016, 06:13   #78
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Re: Chain Stopper Installation Questions

Yes the Maxwell chain stopper can be released under tension by pulling the pin out. The pin is just a swivel point; the forces of the chain pull are focussed between the pawl and the stopper housing.

BTW, there are other options: you can create a multi-phase snubber using several rope diameters, with a thick diameter hanging in a loop but taking the load when a smaller, parallel part stretches too much.
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Old 28-04-2016, 06:39   #79
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Re: Chain Stopper Installation Questions

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Yes the Maxwell chain stopper can be released under tension by pulling the pin out. The pin is just a swivel point; the forces of the chain pull are focussed between the pawl and the stopper housing.

BTW, there are other options: you can create a multi-phase snubber using several rope diameters, with a thick diameter hanging in a loop but taking the load when a smaller, parallel part stretches too much.
Possibly worth a dummy run on getting the pin out. If it works like you say you may still need to drive it out with a big blow if you had to. Then prying the plate out of a heavily loaded chain would be a drama too. I suppose you could always get the angle grinder out if needs must.

I have often wondered what the right thickness and length of snubber was correct. Rather than have a thin snubber with a thick back up snubber, it may well be that a thick snubber sized somewhat over the chain breaking strength (to allow for wet strength reductions and for heating reductions in strength) could be made to work well. Mine is a bit under sized to allow lots of stretch, but I am not sure I am doing things the best way. I say this because the stretch of nylon rope is not linear and a strong rope will still be stretchy. Relying on memory here it is about 10% stretch for 10% load, but 30% stretch at 100% load, so you get quite a lot of stretch at low loads, which of course is what gives you your spring and shock absorption. If you need more stretch then use a longer snubber.
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Old 28-04-2016, 06:48   #80
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Re: Chain Stopper Installation Questions

I will be installing a chain stopper shortly.

Not reliable enough to hold the anchor on a passage, and for this I will have a Devils Claw style device on rope strop, chain or wire.

However, very useful if the windlass craps out and I have to use the winches to pull up the anchor in stages. Running back and forth between winch and foredeck is easier with less chain handling if it is running through a stopper.

Happened to me a few times - enough to persuade me of its value.


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Old 28-04-2016, 08:30   #81
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Re: Chain Stopper Installation Questions

Check my post #59 above, second picture. After pulling the chain tight, I lower the pawl of the chain stopper, then reverse the windlass for as short as possible. This gives an inch or two of chain back, allowing the chain stopper to engage. You can see the slack in the chain between stopper and windlass.

There is no need for angle grinders to get the pin out. It has a large ring on one end and I could pull it out by hand. Being a Jedi, I could do it with the Force as well but anyone should be able to do it with a piece of line through the ring. That is, when the stopper is maintained and the pin, with spring-loaded ball, greased and in good working condition. Use SuperLube, which is synthetic so doesn't harden that much.

I will hunt down some info on snubbers and post when I got it
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