Chain Hooks

[MurrayM]

Also subtract about 15 percent strength if it's wet (nylon loses strength when wet) minus more if there's cyclic loading, minus a bit more if heat is being generated by friction...sleep tight

 

[Delfin]

This discussion was started by Diver Dave's comment that one should use a snubber to protect a swivel. It has nothing to do with other benefits snubbers provide. I maintain that a swivel should NOT be the weak link in anybody's ground tackle.

My chain is Acco's G4, 5/16", galvanized of course. My swivel? Heck the last time I saw it was prior to hauling time last October so I cannot related it from memory to what now is offered by West Marine. Years ago I had another heavy beast swivel that used a clevis pin which I had welded to prevent it from ever pulling out. Personally, I would not consider a SS swivel.

The non SS 5/16" swivels West Marine sells have WLL of around 1500#. Great candidate for protection with a nice stretchy snub line.

A SS Ultra for that size chain and up to a 77# anchor has a WLL of around 5,000#.

 

[Delfin]

Also subtract about 15 percent strength if it's wet (nylon loses strength when wet) minus more if there's cyclic loading, minus a bit more if heat is being generated by friction...sleep tight

And a bit more from sun, salt abrasion, etc.

 

[Benthic2]

But....I'm a little confused here...but if the rolling hitch breaks....your boat is still secured, its just now an all chain rode and you'd probably feel that in the boat if you lost your snubber....right ? IOW...its not a critical failure if the rolling hitch breaks...more of an inconvenience.

 

[foggysail]

The non SS 5/16" swivels West Marine sells have WLL of around 1500#. Great candidate for protection with a nice stretchy snub line.

A SS Ultra for that size chain and up to a 77# anchor has a WLL of around 5,000#.

I remember thinking when I purchased the swivel that it would rip my Maxwell HWC2200 windless from the deck before the swivel would fail.

 

[diver dave]

In any system, there WILL be the weakest link. When that weak point becomes the deck, I would be concerned.

 

[Delfin]

But....I'm a little confused here...but if the rolling hitch breaks....your boat is still secured, its just now an all chain rode and you'd probably feel that in the boat if you lost your snubber....right ? IOW...its not a critical failure if the rolling hitch breaks...more of an inconvenience.

No, that is quite correct. The only reason for bothering with the topic at all is if you want to match the system components to the perceived need. In my case, I doubt I will ever encounter conditions that warrant fretting about my ground tackle, but then again, part of the pleasure of cruising is being a prudent mariner, a.k.a. a paranoid one.

 

[foggysail]

In any system, there WILL be the weakest link. When that weak point becomes the deck, I would be concerned.

Everything has failure limits including decks. I expect my deck is the last thing that will fail with a 4 foot 2X12 under the deck that supports my windlass. Wonder how many boats are out there whose windlass and cleats lack backup plates

 

[Delfin]

I remember thinking when I purchased the swivel that it would rip my Maxwell HWC2200 windless from the deck before the swivel would fail.

I wonder how strong your deck is if a 1500# swivel is not your weakest link. But it sounds like your deck is really strong, so I guess it must be the swivel. Sleep tight.

 

[diver dave]

I had stainless plates under windlass and all cleats on that boat. Was off the boat at the time but i’ll bet the foredeck took quite the deflection.

 

[dhays]

As long as the 40% reduction in strength a rolling hitch results in doesn't bother you, then no problem.

Keep in mind that that a chain hook also reduces the strength of the chain.

I agree with the idea of a soft shackle. I use it around the chain and through a spliced eye in three strand.

 

[Sabre602]

Keep in mind that that a chain hook also reduces the strength of the chain....

Could you explain how the chain is weakened by the chain hook? I see how the entire snubber system...chain hook (or rolling hitch) and nylon line...carry lower tensile ratings than the rode itself, but how does the chain hook weaken the chain?

 

[BruceK]

I don`t like the idea of the whole weight being on one hook on a line inserted into a link. Much more comfortable with the Sea Dog type ss plate with U shaped cut where the chain sits in the U, with 2 lines from the plate taking load back to the mooring cleat. I think/hope that better distributes the load.

 

[Benthic2]

a chain hook will focus the stress on a smaller area of the chain link rather than on the entire link....I suspect it would be a minor impact....and you should never be that close to the capacity of your ground tackle...but theoretically its true.

 

[dhays]

Could you explain how the chain is weakened by the chain hook? I see how the entire snubber system...chain hook (or rolling hitch) and nylon line...carry lower tensile ratings than the rode itself, but how does the chain hook weaken the chain?

There was a report in Practical Sailor a few years ago. They found that any of the then current chain hooks weakened the chain. It had to do with the stress the hook places on the links. A google search should find the article.

 

[foggysail]

I had stainless plates under windlass and all cleats on that boat. Was off the boat at the time but i’ll bet the foredeck took quite the deflection.

Dave— I read many of your posts over time. I have no doubt that whatever you have/had for cleats, windlass and so forth are properly backed up for their application.

 

[Delfin]

I don`t like the idea of the whole weight being on one hook on a line inserted into a link. Much more comfortable with the Sea Dog type ss plate with U shaped cut where the chain sits in the U, with 2 lines from the plate taking load back to the mooring cleat. I think/hope that better distributes the load.

Since Seadog doesn't tell you what the WLL is of their chain grabber, what do you calculate it to be? But, assuming the plate is "strong enough" the strength of this setup will be a function of the bow shackle you attach to each side of the plate. Looks like the maximum is a WLL of 4,000 # or so. Is that enough for you? If so, and you attach enough stretchy line to each side, it should be fine. But at any given moment, you are unlikely to be tensioning more than one side as the boat veers, so what is gained by having the complexity of deploying two lines rather than one?

Sorry, but this setup has never made much sense to me, but I am probably missing something.

 

[Sabre602]

There was a report in Practical Sailor a few years ago. They found that any of the then current chain hooks weakened the chain. It had to do with the stress the hook places on the links. A google search should find the article.

Ahh, thanks. I found it quickly...the article "Can a Snubber Hook Weaken Your Rode?" was published on December 25, 2016. They discuss some concerns expressed by various chain manufacturers about point loading.

However, my position, as was actually supported by the authors at the conclusion of the article, is that real-world application negates any such concerns. Here are some data from the article, loads calculated for a 40-foot monohull in a 60-knot wind:

-- All-chain rode: 4,140 lbs
-- ABYC worst-case scenario, all-chain rode: 4.898 lbs
-- Chain rode with 30 ft snubber of 1/2" three-strand nylon: 1,574 lbs

The loads on the anchor system...both the tensile loads on the chain as well as pulling force exerted at the anchor...are vastly reduced by the use of the snubber system. Even if the presence of the chain hook somehow vastly reduced the strength of the chain, it would still be far more than strong enough to remain a safe and effective rode.

The article concludes that "the argument that a chain hook attached to a properly-sized nylon snubber might weaken the chain and cause a catastrophe is flawed. This is why hooks have been used for decades without an issue."

 

[dhays]

The article concludes that "the argument that a chain hook attached to a properly-sized nylon snubber might weaken the chain and cause a catastrophe is flawed. This is why hooks have been used for decades without an issue."

Yup. Very good point.

I still like a soft shackle or a rolling hitch as they can’t fall off. I do use a chain hook to take the pressure off my windlass when the anchor is stored.

 

[North Baltic sea]

Hi,

My set,

+

+

The rope, the tensile strength of the chain. If necessary, the hard wind, between the rubber snubberOne, will soften the jerk.

I also have another model, otherwise good, but difficult to open, that other model comes off as it often takes the chain up from itself.

NBs