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Old 26-04-2016, 20:14   #31
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Re: Chain Stopper Vs Devil's Claw

Dockhead,

Forget the Sampson post chain stopper thoughts, there's a much better way. Copy my Super Snubber shown in the attached video:



I designed it three years ago while in Mallorca. It greatly reduces the shock load and secures the chain via the dual snubbers to both oversized bow cleats.

The chain claw is an oversized Ultra, and the chafe guards are a must-have.

Ken
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Old 26-04-2016, 22:14   #32
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Re: Chain Stopper Vs Devil's Claw

Quote:
Originally Posted by Dockhead View Post
Thinking about my still hypothetical future boat, and about the ground tackle handling arrangements.

I'm for sure going to have a massive horizontal windlass with a vertical warping drum, and a sturdy samson post, stronger than the breaking strength of whatever chain I'm using.
For the first time I'm the owner of a "massive horizontal windlass" and I hate it. All of my vertical windlasses had a minimum of 180 degrees of chain engagement whilst my horizontal windlass has less than 90 degrees and I've never seen one with more than 100 degrees of chain engagement. Chain does wear, but I've never had five year old chain bounce on a vertical windlass; I've just had to replace all my 5 year old chain that was bouncing on my "massive horizontal windlass". My neighbour, on the marina, has now inherited 80 metres of free chain that works perfectly on his 180 degree vertical windlass. (Yes, my gypsy and the chain match perfectly, and the gypsy was replaced before we gave up on the chain.)
Note to self: never have a horizontal windlass, and particularly never have one mounted slightly below the bow roller!
My plan for the next yacht, is for two massive vertical windlasses each perfectly aligned with their respective super strong bow rollers.

I don't like chain hooks or claws, yes there are very few cases of chains on cruising boats actually breaking, but stretched links can also cause your windlass to jam at a very inconvenient moment. I have a ten metre length of undersize (for the boat displacement) nylon, that I attach with a rolling hitch and two half hitches to the anchor chain and tie off at about five metres; I then let out about eight metres of chain so that we're riding on the nylon. If the nylon stretches out by 60% I wake up with the jolt as the chain takes up. This has only happened a few times in a thousand anchorages and each time I definitely needed to be on deck paying attention.
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Old 26-04-2016, 23:57   #33
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Re: Chain Stopper Vs Devil's Claw

What I find best is to have snubber attached down to the keel http://neverforever.ca/wp-content/up...5/snubber1.jpg This works well with boats with moderate overhang to reduce peak loads on the rode.

BR Teddy
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Old 27-04-2016, 00:23   #34
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by TeddyDiver View Post
What I find best is to have snubber attached down to the keel
It also reduces the the amount of rode (and hence the swinging circle) for the same scope.

Make sure the attachment point is strong enough, as it will be close to, or even below, the waterline.
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Old 27-04-2016, 00:44   #35
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by noelex 77 View Post
It also reduces the the amount of rode (and hence the swinging circle) for the same scope.

Make sure the attachment point is strong enough, as it will be close to, or even below, the waterline.
We installed just such an attachment point on our previous boat, and enjoyed the benefits as described. But, the drawback is that if you wish to veer some additional chain (say if conditions deteriorate), you must first pull in all the slack plus the length of the snubber so that you can untie/unhook it from the chain. I found this to be such a nuisance that I stopped using it except in predicted storm conditions where its advantages outweighed its difficulties. (Besides, under those conditions, I put out all t he available chain ahead of time!)

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Old 27-04-2016, 05:13   #36
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Re: Chain Stopper Vs Devil's Claw

Quote:
Originally Posted by Kenomac View Post
Dockhead,

Forget the Sampson post chain stopper thoughts, there's a much better way. Copy my Super Snubber shown in the attached video:



I designed it three years ago while in Mallorca. It greatly reduces the shock load and secures the chain via the dual snubbers to both oversized bow cleats.

The chain claw is an oversized Ultra, and the chafe guards are a must-have.

Ken
That's a very cool snubber setup, but that's not really what we're talking about -- rather belaying the chain, which is a different function. Snubber, no matter how cool, is no substitute for a chain stopper or strop.

My snubber is much simpler, but is adequate for my purposes. Over the bow roller there's no chafe to speak of. Like someone else who posted here, I prefer to tie it on, rather than use a hook.
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Old 27-04-2016, 05:20   #37
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Re: Chain Stopper Vs Devil's Claw

Quote:
Originally Posted by Jim Cate View Post
We installed just such an attachment point on our previous boat, and enjoyed the benefits as described. But, the drawback is that if you wish to veer some additional chain (say if conditions deteriorate), you must first pull in all the slack plus the length of the snubber so that you can untie/unhook it from the chain. I found this to be such a nuisance that I stopped using it except in predicted storm conditions where its advantages outweighed its difficulties. (Besides, under those conditions, I put out all t he available chain ahead of time!)

Jim
Exactly my experience. PITA. We had the eye on my last boat. Never installed one on this boat.
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Old 27-04-2016, 05:22   #38
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by Island Time O25 View Post
This may sound naive (stupid?) but I'll ask anyway. What if the windlass and the structure it is bolted to are the strongest pieces at your bow - do you still want the load off of them?

When we installed the older heavy duty Nielsen H700 we epoxied several 1/4" layers of G10 (2 but possibly 3, I will check next time I'm at the boat) and the G10 plates were about 3-4" larger all around than the foot print of the windlass. The back up plate is not just around the bolts, it is a large piece which is way larger than the windlass' footprint. We did the same for the cleats but the G10 backing plates were about 1-2" outside the cleat's footprint as there was no space for more. And there is very little room on deck for a robust stopper's backing plate.

For now I am using the method described by one of the previous posters i.e. 2 nylon ropes with hooks which go from chain to cleats. But being a fair weather sailor for now (one of Admiral's requests at this point but I'm working on it )) ) I don't really anchor during severe weather, etc. so this set up for now is fine for short excursions on shore when away from my mooring, etc. But I wonder if being the strongest attachment at the bow, the windlass may not be the worst possible place to use as a stopper in addition to the stopper or is it anyway?
The problem is the windlass and its clutch and/or gears. Not designed to take these loads at all. Strong attachment of the windlass doesn't help you.

You will break the gearbox or, if you're lucky, the clutch will slip and you will merely lose your chain. If you're asleep when this happens, you may lose your boat.
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Old 27-04-2016, 05:24   #39
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Re: Chain Stopper Vs Devil's Claw

Quote:
Originally Posted by Kiwi. View Post
For the first time I'm the owner of a "massive horizontal windlass" and I hate it. All of my vertical windlasses had a minimum of 180 degrees of chain engagement whilst my horizontal windlass has less than 90 degrees and I've never seen one with more than 100 degrees of chain engagement. Chain does wear, but I've never had five year old chain bounce on a vertical windlass; I've just had to replace all my 5 year old chain that was bouncing on my "massive horizontal windlass". My neighbour, on the marina, has now inherited 80 metres of free chain that works perfectly on his 180 degree vertical windlass. (Yes, my gypsy and the chain match perfectly, and the gypsy was replaced before we gave up on the chain.)
Note to self: never have a horizontal windlass, and particularly never have one mounted slightly below the bow roller!
My plan for the next yacht, is for two massive vertical windlasses each perfectly aligned with their respective super strong bow rollers.

I don't like chain hooks or claws, yes there are very few cases of chains on cruising boats actually breaking, but stretched links can also cause your windlass to jam at a very inconvenient moment. I have a ten metre length of undersize (for the boat displacement) nylon, that I attach with a rolling hitch and two half hitches to the anchor chain and tie off at about five metres; I then let out about eight metres of chain so that we're riding on the nylon. If the nylon stretches out by 60% I wake up with the jolt as the chain takes up. This has only happened a few times in a thousand anchorages and each time I definitely needed to be on deck paying attention.
First time I ever heard of anyone having this problem with a horizontal windlass. So that's a useful data point -- anyone else experience such a thing?

I had a horizontal windlass on the previous boat (exactly the same one as on Snowy Petrel's boat; can't remember the name). Never any trouble.
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Old 27-04-2016, 05:28   #40
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by Bulawayo View Post
Interesting......see the last edition of Practical Sailor. There are several caveats about the design of chain hooks including the Mantus which has a 'sharp' edge on the inner face which testing demonstrated significantly reduces the strength of the chain. Scary - proceed with caution!!
Yes, I don't like chain hooks on snubbers. I use a rolling hitch as I have for decades.

Chain hooks for snubbers are solutions in search of a problem which does not exist IMHO. Rolling hitch is more secure, stronger, more gentle to the chain, cheaper, what's not to like?


For belaying the chain, however, if there's no rope in that system, you have no choice but to use a hook. But since this system is never loaded except in an emergency, I think no problem with wear. Security, however, is paramount, which is why I don't really like the simple chain hook which I use now, which is just like the one on Snowy Petrel. I'd like to have one that locks in place.
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Old 27-04-2016, 05:31   #41
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by Paul L View Post
A,
Using the burst strength of the various components is a large simplification. In reality the system is dynamic, not static. If you burst your snubber, then it has absorbed a lot of energy in the process. Maybe enough to save the chain and then fallback to the chain stopper -- till you can get another snubber in place. I've snapped 5/8" brait snubber before, while all the other components held fine and were undamaged..
THIS

This is exactly why you can't use a snubber to belay the chain.

The snubber will be better or worse for this depending on how large and long it is -- so what is its capacity for absorbing all the energy as it "works", doing its job as a snubber.

In any case, however, the real breaking strength of a working snubber is far less than the nominal rated strength. Remember besides internal heating that nylon loses much of its strength when wet.

Snubbers which are really doing their jobs will occasionally break. Terrible idea to rely on that to keep your boat off the rocks.
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Old 27-04-2016, 05:45   #42
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by Dockhead View Post
I had a horizontal windlass on the previous boat (exactly the same one as on Snowy Petrel's boat; can't remember the name). Never any trouble.
Ummm, I think you might be thinking of Panope's lovely boat, "Panope" not mine which currently has no windlass...
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Old 27-04-2016, 06:39   #43
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Re: Chain Stopper Vs Devil's Claw

There are no sharp edges on the Ultra chain hook which will damage or cut the anchor chain.
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Old 27-04-2016, 06:48   #44
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Re: Chain Stopper Vs Devil's Claw

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Ummm, I think you might be thinking of Panope's lovely boat, "Panope" not mine which currently has no windlass...
Sorry, yes, Panope.
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Old 27-04-2016, 06:48   #45
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Re: Chain Stopper Vs Devil's Claw

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Originally Posted by Dockhead View Post
THIS

This is exactly why you can't use a snubber to belay the chain.

The snubber will be better or worse for this depending on how large and long it is -- so what is its capacity for absorbing all the energy as it "works", doing its job as a snubber.

In any case, however, the real breaking strength of a working snubber is far less than the nominal rated strength. Remember besides internal heating that nylon loses much of its strength when wet.

Snubbers which are really doing their jobs will occasionally break. Terrible idea to rely on that to keep your boat off the rocks.
Sure that's true regarding simple old school snubber systems, but if you build yourself a new school snubber similar to the Ultra system pictured, then put it on steroids... oversizing it for your boat, these issues will be a problem of the past.
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