By RainAgain - 16 Mar 2012
Well I found the forum and this is really an experiment to see if I can work out how to press the buttons but I have to post something so I thought I would ask about snubbers.
I had always thought that snubbers were to take the snatch out of your anchor cable and since mine is all chain cable should read chain. Since stretch was important and ultimately my boat is anchored by chain made off properly to a samson post and not riding on the windlass I tended to use light stretch nylon line until last november that is. At the end of last year I took a short trip from Lagos to Gib and found myself anchoring in some really foul weather. We had over 50knots for many hours with the storms extended over several days. I broke four snubbing lines during this time - all of them at the rolling hitch on the chain. The lines were 18mm. I use a rolling hitch because a chain hook just looks all wrong to me placing a point load on an individual link in the chain but I am very willing to listen.
Any comments?
Ta, Mark
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By RobbieW - 16 Mar 2012
Sounds as if the rolling hitch suffers the same point load problem that concerns you about using a hook! I dont have the benefit of a samson post to wrap the chain around, the nearest thing is the cleat on top of the windlass. I do use a hook snubber, hadnt thought about a point load problem with that, mainly because I inherited it with the boat. I also havent anchored in the extended bad conditions you describe, food for thought.
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By simoncurrin - 16 Mar 2012
Mark,
I 've used a chain hook for about 10 years and never yet had a problem. The conditions you describe though do sound exceptional so I don 't really know how my system would hold up with sustained 50kn and, presumably, higher gusts?
Simon
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By RainAgain - 17 Mar 2012
Understand Simon but I was with a lady who lost a boat when she was anchored off a beach in Senegal. There was an exdceptional wave and the chain broke. She is convinced it was due to the chain hook she was using - you just have to look at the things to see how point loading is applied to the individual chain link. When I was down in Patagonia they routinely used a double chain hook where the load is taken on both sides with a keeper - it looked much gentler on the chain but I have never been able to find one here. Kind Regards, Mark
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By alshaheen - 18 Mar 2012
On Al Shaheen for our snubber we use a 25mm cable-laid line with a hard eye spliced into it and shackled to a large cast galvanised hook. The hook, of course, lies across a link in the 10 mm chain and the load is transferred to the end of the link above. I don 't see this as causing any more of a point load than normally exists through transfer of load from one link in the chain to the next.
We make off the snubber line to the samson post (100 mm alloy tube welded to deck and through to the keel!) We use a long piece of 38 mm ID plastic tube to protect the snubber line where it runs through the bow rollers. We lay to a cat 1 hurricane with this arrangement and 70 mm of chain with no problems.
The main thing is to have enough elasticity in the complete rode to minimise snatch loads. Our most scary time was anchored in shallow water (5 metres) in Managua lagoon with a 2 mile fetch to windward, a 30 knot wind causing a 1.5 m very short sea and a coral reef 300 m to leeward. Even with 50 m of chain veered the snatch loading was terrible and after the second night I lost my nerve and moved out of the lagoon! But the snubber and chain survived OK.
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By bbalme - 19 Apr 2012
I 've been using 1/2" triple braid nylon for the snubber - seems to work fine - though I 'd really like to try Evans Starzinger 's approach with climbing line - just not sure what grade to get since I 'm not a mountaineer. I like the idea of lots of stretch!
I too used to use the chain hook - but found that on a non windy night, with a slack cable, the hook would fall out - then the wind would pipe up and we 'd start snatching! Inevitably it 's be raining and 2:00am when I had to reattach the hook! I now use a rolling hitch and so far have not had issues... :unsure:
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By archive - 8 May 2012
For the past 4 years I have followed Evan 's suggestion and use 9mm climbing rope, 12 meters long. We have anchored in near 40 kt winds with a lot of chop and I think it does very good job.
But you do need to find the right climbing rope (I was a climber for many years so I have a few old ropes.) The rope you see in a climbing store for sale by the meter is usually static line and not the full stretch type. The static line does not stretch as much and is used for climbing protection points. A climbing rope is usually only available 50 meter lengths. If you are near a good mountainnering shop you may put up a note offering to buy a used climbing rope. After some point climbers "retire" their ropes usually because there is a cut or weak point. These would be cheap and work fine.
I have also used a chain hook and like the ease of removing it if we need to put out more chain. Having enough slack in the chain above the hook seems to prevent the hook falling off, even in no wind drifting conditions.
Jim
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By Vanderveet - 6 Sep 2014
We use a chain hook to a short length of 5/8 line, which then goes to a bridal which we pass through the fairleads to our sampson post. We find the bridal helps reduce swinging.
Used to use a basic chain hook, but as above found this would fall off when no strain. Past two years have had good success with the Mantus chain hook, easy to put on and stays attached.
Been in 30 kts in an open anchorage for 12 hours and worked well.
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By alshaheen - 7 Sep 2014
Surely, bridle? No weddings here!
The snubber should be set so that it is supporting the weight of the chain with the length of chain between the hook and the boat hanging in a loop so that the snubber is always taking all the strain imposed by the chain. When set up like this no chain hook should fall off since it is always under some strain even in conditions of no wind.
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By Dick - 21 Sep 2015
Good day all,
Firstly, I would want the managers to consider moving this topic to the ground tackle/anchoring area where I believe it would more likely get the notice it deserves.
Next: I do not see the point loading of a chain hook as being an issue.
There are a number of reasons to argue against the use a chain hook, but the most compelling to my mind is that: You are awakened at 00darkThirty and the wind is up, seas rising, and it is starting to drizzle and you want to veer more chain. With most chain hooks, the chain needs to be taken up (just when you want more chain) often needing the engine to do so. With a rolling hitch, you just let the snubber go out with the chain and bend on another (which for me would be a handy dock line). This is a few seconds operation rather than a bit of a fire drill. Retrieval is done when you up anchor. With most chain hooks (unless they are moused and life is too short to do this every time I anchor) you are unable to just cast them off as you will lose them.
As to the rolling hitch breaking that started this thread. I suggest a modified rolling hitch as shown by a picture in this article I wrote (http://www.stevedmarineconsulting.com/ezine/index.php?p=22). It has an extra turn at each end as shown in the picture. Another OCC member, John Harries on Morgan’s Cloud, and a rising guru in the recreational offshore sailing world (see Attainable Adventures Cruising web site) recommends two regular rolling hitches in a row to serve the same function. Regardless, the knot (all knots actually) benefits from a couple of seconds of being tightened by hand.
The article (whose url is above) spells out in more detail my reservations about chain hooks (also swivels) and talks about the use/design of snubbers.
My best, Dick Stevenson, s/v Alchemy, Hindeloopen, The Netherlands
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By Dick - 21 Sep 2015
Another thought:
I would suggest never securing you chain to a samson post. Chain is most vulnerable (as are your deck fittings) when they become 2 blocked- stretched link to link from fixed points: anchor to Samson post. Something has to give. And this does happen. For most anchoring situations the chain gets 2 blocked in gale conditions with some regularity which is why a snubber is so important.
When in challenging weather, I sometimes back up my snubber with another short snubber rolling hitched to the chain. This snubber is then ready to go if I wish to veer more chain and will take the load if the first snubber breaks (never happened, but we know it could).
I always leave the chain free to run (a bit of friction keeps the chain from bouncing out). If things really get out of hand, the chain is free to go out till it reaches the nylon attachment of the chain’s bitter end to the boat which should hold the boat till I get things sorted. The last thing I want is the chain locked to the boat without any form of shock loading relief.
My best, Dick Stevenson, s/v Alchemy
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By simoncurrin - 21 Sep 2015
Dick I have moved as suggested.
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By DariaBlackwell - 22 Sep 2015
An interesting thing occurs with the new scoop anchors like the Spade, Rocna and Ultra. Peak loads tend to be snatch loads and they are accentuated with the new anchors because they don 't budge. Boats that veer at anchor and boats that surge at anchor (catamarans) will observe high snatch loads.
So it is important not only to deploy an effective snubber, but also to reduce the snatch loads as much as possible. The best way to do that is with more scope. But one can also deploy bridles to distribute the load or riding sails to reduce veering. These two reports have some information you may find useful.
http://www.practical-sailor.com/issues/37_17/features/anchor_testing_rode_loads_10784-1.html
http://www.mysailing.com.au/news/testing-the-new-generation-of-anchors
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By Dick - 22 Sep 2015
Hi Daria,
I agree, peak loads are always snatch loads regardless of what anchor is planted in the bottom. I observe also that my Spade (and other new generation anchors) exacerbates snatch loads by being scoops rather than plows and do not budge. That is a good thing but it also accentuates our need for a viable system for dampening/averaging the forces.
That said, I am not convinced that the snatch loads, in adverse conditions and when things really get ugly, are all that different. Before the Spade, I had some quite ugly conditions with my CQR. Once set, it worked a peach and, the peak load of a big snatch was not going to be all that different if the CQR “plowed” and inch or two, from my present Spade which may not budge. (That said, the Spade is just a far superior anchor).
More scope is the solution that answers all anchoring problems, but is one that is often hard to come by in cozy and/or crowded anchorages. All boats experience snatch loads, some clearly more than others. The mizzen on my old yawl was up for weeks at a time and kept us weather-cocked to the wind and hugely mitigated snatch loads from wind. Riding sails I have observed do not, at casual inspection, seem to very effective nor am I convinced that a bridle calms veering and may even exacerbate veering (I have experimented with this and on 2 boats found no difference in veering, bridle vs single line). However, the worst snatch loads I have experienced, are always related to seas: to that moment of adverse synergy where a random bigger wave/swell meets the harmonic of the boat’s movement and the bow rears up and back dramatically just when the rode loads up. Then you find out if your snubber is effective.
What dampens the forces is stretch which is one of the problems with a bridle (caternary does little in adverse conditions because there is little of it). Although boats often load one side of the bridle and then the other, in a snatch, both sides get loaded and the stretch is halved just when you need it most. Bridles also almost always need a chain hook, an unnecessary complication both in the initial deployment and in a wish to veer more chain when that occurs.
Much better to my mind to tie on a rolling hitch (modified a bit as shown in a pic in a recent url) with one line that goes out right next to the chain. I have done this for decades with no chafe issues (clearly boats vary in this regard). I use 7/16 inch (11mm) nylon 3 strand. Its length is 35 feet and I vary how much I use according to the conditions at the time. This is with a 40 foot, 16+ ton cutter. The snubbers strength strength is more than adequate.
The one caveat to a really stretchy snubber that I have yet to work out is the Yo-Yo effect: bouncing back after a gust only to give a longer run to the next snatch. All things considered, I still go for more stretch.
My best, Dick Stevenson, s/v Alchemy
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By bbalme - 22 Sep 2015
It 's interesting how practice develops - when I responded 3 years ago to this thread, I was using a rolling hitch to attach the 1/2" double braid snubber - nowadays I 'm using a 30ft bridle of dynamic climbing rope attached with a chain hook! We always deploy a snubber.
One thing I do which I don 't see many doing, is to veer about 20ft of chain after attaching the snubber. This not only loads the snubber to prevent the hook from coming loose, but I also think it adds a little catenary right where it 's useful, to decrease snatch loading (as opposed to adding a kellet to increase catenary closer to the anchor in an attempt to lower the pull angle on the anchor).
I like the bridle - I effectively have two snubbers should one give way - it also does reduce veering somewhat on Toodle-oo! - I think!
I don 't see the chain hook as imparting any more of a point load into the system than the point loading that is inherent in chain links. I also don 't understand the difficulty in veering more scope with a hook over a rolling hitch - if you can bend on more line to the snubber attached via a rolling hitch, why can 't you do the same with the one with a hook?
I often see snubbers that are just a couple of feet long, with the chain only loose by a few links... That seems to me to be hardly worth the effort of putting out a snubber at all - stretch requires length to be effective...
My 2 cents...
As a PS: The admiral and I decided on Friday morning that we would NOT buy a back-up anchor at the Newport Boat show that day - instead we 'd scour ebay over the winter and see if we could get a deal. We came back from the show with a 55lb Spade! Oops!
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By Dick - 23 Sep 2015
Good morning Bill,
I know I have known your first name, but it escapes me now, so forgive me for addressing you as I just did.
I believe a Spade makes a superb bower and a superb back up anchor as, unlike some of the other alternatives, it comes apart and is more easily stowed. It also is less likely to ding furniture if stowed below when you move it around.
I agree that point loading concerns with chain hooks is a non-issue. And also that veering chain between the snubber connection and the boat is a good thing. Not sure it makes a load of difference kellet-wise, but it should be of sufficient length to deal with snubber stretch so as to never get 2 blocked.
I apologize, I was not clear why a chain hook made veering more chain more difficult as you understood me to do so by adding more snubber to the already deployed snubber via a rolling hitch (I would never recommend a rolling hitch be put on a nylon line that was loaded and unloaded: too much diameter change on the loaded line).
On Alchemy, when needing more chain in a fire drill of some sort, I actually just throw off the old snubber (as it is attached to the chain-as opposed to a hook which can fall off- I can retrieve it when upping anchor) and attach a new one (usually an always handy dock line) with a rolling hitch to the chain at whatever length I wish and the snubber then just follows the chain out. This is done right in front of the windlass with no acrobatics necessary and in a quite safe position. No windlass use or engine use is needed and the whole operation takes a minute or so, leaving one exposed to the elements for a very short time.
With a chain hook, one usually has to bring the chain in (hard on the windlass or need to start the engine) just when you want more of it as the hook is usually in need of repositioning and will be lost if just cast off. For many boats there is then an acrobatic moment where one needs to attach the hook outside the roller, not easy or safe in bouncy conditions
I am interested that you feel that a bridle cuts down the yawing of your boat somewhat and that you like having 2 legs as this provides back-up. I like simple and to me a bridle is too complicated for the (possible) benefit it delivers. A single snubber attached quickly with a rolling hitch and sent out with the chain is just so quick, easy, and safe. I do attach a back-up snubber when expecting (or in) a bit of a blow (once every year or two), but it has never come into play- yet: it will someday.
I have no experience with climbing lines. What do you see as the advantages? My 7/16 inch 3 strand nylon stretches impressively and has a 6000 pound average breaking strength. Nylon is an amazing material.
My best, Dick Stevenson, s/v Alchemy
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By archive - 23 Sep 2015
Climbing ropes are designed to stretch the maximum amount before the breaking point (to avoid injury to a climber) so they work great as a snubber. I think the big advantage is that you can buy 11mm x 50 meter used climbing ropes for US$20. Just put up a sign in the local outdoor shop.
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By Dick - 23 Sep 2015
Hi Jim,
Thanks for the reply and the info.
Maybe you know your ropes well enough to inspect what you are getting when you buy used ropes. I know some get condemned after one major shock loading.
I like to know what I am using in my ground tackle system, so I suspect if price is the only advantage, then I will stick with a premium 3 strand nylon. I can 't imagine I would want more stretch than my 7/16 gives me: if so I would go to a larger diameter rope.
My best, Dick Stevenson, s/v Alchemy
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By Dick - 23 Sep 2015
Senior moment. Last sentence in previous comment should read "smaller" rather than "larger". In fact I used 3/8 inch for years and moved up as I thought it too springy. Dick
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