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Old 24-02-2018, 04:25   #1
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How long is your snubber

I was reading an article about anchoring were the writer said that you should have a snubber of about 12 metres long so it, when being used, should reach to just above the bottom. What length of snubber do you use? Mine only goes to about just above water surface
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Old 24-02-2018, 04:30   #2
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Re: How long is your snubber

Ours is about 25ft (7.5m). Basically when tied is supplies about 15 to 25 ft of stretchy line and the hook sits probably 10 ft under the surface.
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Old 24-02-2018, 04:47   #3
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Re: How long is your snubber

Mine are s 6’ or so and sets just below the surface.
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Old 24-02-2018, 04:51   #4
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pirate Re: How long is your snubber

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I was reading an article about anchoring were the writer said that you should have a snubber of about 12 metres long so it, when being used, should reach to just above the bottom. What length of snubber do you use? Mine only goes to about just above water surface
Ditto.. likewise.. my snubber's purpose is to absorb shock loads and transfer them to a strong bow cleat taking the load off the windlass.. I then have on deck a chain stopper to take any load should the snubber fail.
I see no point in having a snubber that long.
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Old 24-02-2018, 05:39   #5
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Re: How long is your snubber

Anticdotalie (sic), of the thousands of boats I have seen at anchor, none of them had snubbers that long. Most only go a few feet under water.
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Old 24-02-2018, 05:42   #6
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Re: How long is your snubber

Mine is the same length as my dock lines. 'Cause, hey, I've got this line on my foredeck that's got an eye splice in it, already over a bollard post.

Throw a rolling hitch in it to tie it to the chain and Bab's your auntie.

Short answer; 15'.
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Old 24-02-2018, 05:50   #7
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Re: How long is your snubber

Mine is a bridle and it’s long enough to take one end to a midship cleat, in case the wind and swell are from different directions.
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Old 24-02-2018, 06:00   #8
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Re: How long is your snubber

Mine is about 4m long. Goes about 1m under water or is at the surface in strong winds. Attached with a soft shackle. Its amazing how much stretch/shock absorption/noise dampening you get even from that length of nylon.

I saw a guy with one that must have been about 15+m long. Water was only 3m deep(jolly harbour antigua) and it looked like he must have had it attached only a few meters behind his anchor. Kind of defeats the purpose a bit doesnt it?
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Old 24-02-2018, 06:31   #9
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Re: How long is your snubber

If you have a double bow roller you can use a longer line run over the spare roller and taken to an aft cleat. Longer snubbers tend not to run out of stretch if you are anchored in shallow water and your chain cannot form a fairly long caternery.
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Old 24-02-2018, 06:42   #10
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Re: How long is your snubber

I have about 25 feet but sometimes in calm anchroages I just put out enough to take the load off the windlass, other times it's all out.
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Old 24-02-2018, 06:54   #11
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Re: How long is your snubber

Probably not relevant as we are a cat using a bridle but length is such that at rest in a calm anchorage the hook to chain is about 1/2 meter under the surface.
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Old 24-02-2018, 07:10   #12
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Re: How long is your snubber

Mine are 30 feet or about 9 metres, rigged as a bridle, so 30’x2. But I only put out the full length as needed. Most of the time I’m probably riding on around 15’ to 20’ x2.
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Old 24-02-2018, 07:12   #13
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Re: How long is your snubber

IIRC Evans had addressed this issue in an earlier thread. I believe he quoted someone who did some research and Cake up with some guidelines for, what conventional wisdom would call, long and thin snubbers. There was some pretty good logic to it.

Briefly the purpose of a snubber is to absorb shock loads. The longer and thinner the snubber the more it will stretch and the greater the shock it will be able to absorb. A longer snubber will distribute the force over a greater length and no one point will be stressed as much, it will last longer.

My personal idea is to have the snubber just short enough to not foul the prop when the inevitable happens.

So I strive for about 25’ - 30’ or 1/2” snubber on a 44’ 40,000 lb sailboat. I’ve not had a problem with this set up in 40+ knot winds with a fair chop. I believe it is good for substantially more. I also have a ABI chain stopper substantially mounted.

My apologies to Evans if I have miss-represented him.
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Old 24-02-2018, 07:21   #14
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Re: How long is your snubber

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I was reading an article about anchoring were the writer said that you should have a snubber of about 12 metres long so it, when being used, should reach to just above the bottom. What length of snubber do you use? Mine only goes to about just above water surface
So what we have learned so far from comments is that people have no real rational for how long their snubber should be, they do what "feels good" to them. I will say categorically that 6 feet is uselessly short, and 12 meters is longer than needed. The depth of the water, and the height of the bow roller really have nothing to do with how long a snubber should be because they have nothing to do with what a snubber is actually used for.

Selecting a snubber size and length is not something that should be done without understanding what a snubber is for and what it can do for us. So what is a rational thought process for how long a snubber should be? Note that is is a pretty qualitative analysis. You could do a lot of calculations, and engineering analyses and come up with a more precise answer, but I really don't think that is going to give you a "better" answer...

First thing, is most of the sailing literature way over estimates the amount of shock absorption the chain catenary actually gives you. Just go up to the bow in 20 knots of wind and LOOK. You'll see the chain has almost no sag left. When the weather picks up to the point you start to worry about your anchor, there is no significant sag left. So we need another tool to act as a shock absorber.

The first purpose of a snubber is NOT to take the load off the windlass, although it does do that important job. Its primary job is to "snub" the shock loads on the anchor and boat in rough weather. It does this by stretching under load.

Using a snubber that is too short, or one that is too large in diameter, will both reduce the stretch that is available.

Most 3-strand nylon line will typically stretch about 25% before it breaks. Obviously we don't want to break our snubber! So a good place to be is to having the snubber stretch more than 3% and less than 10% of it's total length at the highest anchor loads. If you look at it that way you can see that a 6 foot length of rope will stretch less than 6 inches... not nearly enough to absorb any meaningful wave or wind shock load.

A total stretch of about 3 to 5 feet under the highest loads seems to me to be reasonable in rough conditions to absorb shock loads and help keep the anchor set well. That means a snubber of 30 to 50 feet is what I use when it is rough. If the weather is calm, half that is reasonable.

The snubber should be between 50% and 100% larger in diameter than the chain size. (i.e., 3/8" chain matches with 9/16" to 3/4" line") Smaller is not strong enough, bigger reduces the stretch that we are looking for. That size selection puts the WORKING load limits for the line as a rough match to the chain itself (for G4 hi-test chain).
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Old 24-02-2018, 07:25   #15
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Re: How long is your snubber

The reason to have a long snubber is to increase the stretch for better shock absorption. This is especially important if your boat tacks at anchor. During a "tack" the force on the anchor is higher because the boat is turned somewhat sideways to the wind exposing more windage. When it reaches the end of a "tack" and turns back, there is an even higher momentary force as the bow is accelerated from going one direction to the other. You can easily see this by watching your snubber stretch and ease during the tacks.

Once the chain is taught - which happens at a surprisingly low wind speed - it offers no shock absorption. It then transmits the shocks directly to the anchor which can cause it to drag. Worse, the chain can break.

A short snubber is fine in light conditions. You can see it stretching a few inches with ever tack. But in a strong wind you want feet of stretch not inches. You also don't want your snubber line to be too large diameter as it then won't stretch enough. On a 50,000lb boat I have a 30ft piece of 7/16" three strand nylon twisted line. I don't use double braid as it doesn't stretch as much. I put out between 15ft and 20ft of it. I have a 2nd 3/4" snubber that I attach in storm conditions that would only come into play if the 7/16" one failed.

And remember to let out a big enough loop of extra chain so that it doesn't prevent the snubber from stretching. The moment the chain becomes taught, you've lost all your shock absorption.
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