Chain Snubber

[s/v Jedi]

I have nothing against the rolling hitch (use it myself now and then) but the chain hook only gets undone when it's not correctly deployed.

- never let out so much snubber that it can reach the seabed
- give enough slack in the anchor chain like on the photo I posted here

the weight of the chain below the hook plus that of the loop hanging down from above the hook, will make sure it stays attached.

cheers,
Nick.

[GordMay]

Originally Posted by Kettlewell

... This indicates to me that anchor loads are a lot lower than the ABYC guidelines.

Evidently, true for Static Loading; but not at all true for Dynamic loading.
Anchor Loads Revealed - By Don Dodds
➥ http://northpacificresearch.com/down...d_revealed.pdf

[Kettlewell]

Evidently, true for Static Loading; but not at all true for Dynamic loading.
Anchor Loads Revealed - By Don Dodds

I try to avoid anchoring in unsheltered areas with large seas. In any case, like I said I've never had the 3/8" nylon snubber break while anchoring in winds of up to around 100 mph a few times, and numerous gales, though mostly in relatively sheltered places. However, if I was expecting strong winds like that I would add chafing gear, more snubber, and possibly even upgrade to maybe 1/2", but anything over that is overkill and defeating the purpose on a boat in the 20,000 lb. range. For normal day-to-day use, 3/8" is plenty. You want the snubber to provide some elastic give to cushion the loads on everything.

[SV Liberty]

Agree with Nick's points above (don't let hook reach bottom, drop a big loop of chain). We use a 25 or so foot length of 1/2" three strand nylon, with a stainless cunningham hook (I think that's what its called) on the end. The hook goes right thru a link on our 5/16" high test chain, and I let out the snubber and chain together, tie off the snubber, then drop a big loop of chain. I use a piece of garden hose at the bow roller, and another piece of hose from the cleat behind the windlass for a short bit where the snubber would otherwise chafe against the hawse pipe built into the windlass (we have a Simpson Lawrence Sea Tiger manual windlass). In light conditions I let out enough snubber to go from the bow roller to the water or a little deeper, and I will let out snubber rode as the wind builds if necessary. I try generally to keep the length of rode shorter than the depth of water, but if the wind's blowing then of course that doesn't matter. We've had 25' out in 8' of water in a hard blow. The 1/2" line provides great shock loading.

Dave

[lancelot9898]

I've used a rolling hitch in the past and had a few occassions where it has come undone since I use a bridle with two lines coming from the boat so that as the boat "hunts" back and forth a load is one line and then the other. I now use a Klemheist Knot to tie the bridle to the rode (chain/line)and have no issues with that. It can be tied easily on deck and passes over the bow roller of the sprit.

[SV Demeter]

Originally Posted by s/v Jedi

my favourite design:







ciao!
Nick.

Nick why the lashing instead of splicing directly to the hook?

[Capn Morgan]

Perhaps I should add that I very rarely (if I can help it) anchor with less than 25ft under my keel. I just don't like being close to anything. I put out a lot of chain so that the shear weight of the scope acts as a spring. This way the load on the cleat always increases gradually and there are no shock loads, which is why I keep the snubber short.

Nick above recommends rightly keeping it so it doesn't touch the bottom, I would not be able! I always let out a lot more chain once the snubber is taught and even so, I have had the hook coming undone, and yes, it looked just like your picture, Nick. I just don't know what kind of movement causes it to let go. In the mean time I will stick to the rolling hitch. I'm also interested in the question above, why the lashings?

Best

M

[Auspicious]

My snubbers. They aren't nearly so white anymore.

[Cotemar]

Auspicious,

Where did you buy those SS hooks with the keepers pins on the ends? Never seen those before.

[Auspicious]

Google Wichard chain hook

[Cotemar]

Auspicious,

Nice. Going to have to buy one of those Winchard chain grips

Chain Grip Hook

Mark

[Dockhead]

Originally Posted by Capn Morgan

Perhaps I should add that I very rarely (if I can help it) anchor with less than 25ft under my keel. I just don't like being close to anything. I put out a lot of chain so that the shear weight of the scope acts as a spring. This way the load on the cleat always increases gradually and there are no shock loads, which is why I keep the snubber short.

You will get the shock loads when you run out of catenary. Unfortunately, that's also just when the s**t is hitting the f*n in the anchorage. Personally, I like to put out a snubber commensurate with the chances of a bar-tight chain -- if there is a risk, then I use my big snubber let all the way out (10 meters). That's when you really need the snubber altogether.

Concerning your anchoring depths: I just read something surprising about them. That the dynamic loads on your ground tackle are directly related to the depth, NOT to scope in any meaningful way. The shallower the water, the bigger the dynamic loads. So anchored out in deep water with lots of chain out is a good way to do it from that point of view.

[Capn Morgan]

Originally Posted by Dockhead

You will get the shock loads when you run out of catenary. Unfortunately, that's also just when the s**t is hitting the f*n in the anchorage. Personally, I like to put out a snubber commensurate with the chances of a bar-tight chain -- if there is a risk, then I use my big snubber let all the way out (10 meters). That's when you really need the snubber altogether.

Concerning your anchoring depths: I just read something surprising about them. That the dynamic loads on your ground tackle are directly related to the depth, NOT to scope in any meaningful way. The shallower the water, the bigger the dynamic loads. So anchored out in deep water with lots of chain out is a good way to do it from that point of view.

Indeed, the deeper you anchor the more weight of chain (catenary) that is acting as a spring. If you use at least 4 times chain to depth ratio it is unlikely you will be pulling straight from the anchor under normal conditions. If I expect a stiff breeze I let out more. If it looks like all the chain will go out I'd rather fight it at sea. My concern is protecting the bowsprit and rigging, as the chain comes down from it, transmitting loads directly to the top of the mast etc. Here is where the snubber comes into play, going from the cleat through a hawse pipe to the chain via a hook or rolling hitch. I'm still sold on the knot for the time being.

[estarzinger]

Originally Posted by Cotemar

Auspicious,

Nice. Going to have to buy one of those Winchard chain grips

Unfortunately the design of the little 'keeper pin' is not very robust and they often bend and jam.

[Paul Elliott]

Do be aware that in hurricane conditions a nylon snubber can melt from the heat of internal friction, and chafing gear can trap the heat. Things have to get really bad before this is an issue, but I have a friend who lost his boat on the beach when his snubbers gave way. He inspected the line-ends afterwards and they had melted from the inside, not chafed from the outside. I don't know if he had chafing gear on the lines.

There are ways to mitigate this problem, for example with sections of low-stretch line between the cleats and the fairleads, perhaps down to the waterline, thus keeping the nylon snubber submerged and cooled. It seems to me that going with a thicker and longer snubber would also help in this regard.

I've just got the standard nylon snubbers, but then I don't do enough exposed anchoring to make this an issue. If I were seriously cruising I would look at my options.