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Old 11-08-2014, 05:50   #31
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Re: Snubbers - Or the Lack of Them

Snowpetrel, interesting comment about catapult to windward. When I first bought the boat some 2 decades ago, at that time I was not in the habit of using a snubber. However, I had a built in snubber considering that I anchored on 80 feet of 3/8 inch BBB chain and then had a splice of 5/8 inch 3 strand nylon. During a Cat 1 hurricane I had over a 150 feet of rode out and the catapult action after experiencing peak wind gusts of 90 some knots was something that I don't want to experience again.
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Old 11-08-2014, 05:54   #32
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Re: Snubbers - Or the Lack of Them

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Snowpetrel, interesting comment about catapult to windward. When I first bought the boat some 2 decades ago, at that time I was not in the habit of using a snubber. However, I had a built in snubber considering that I anchored on 80 feet of 3/8 inch BBB chain and then had a splice of 5/8 inch 3 strand nylon. During a Cat 1 hurricane I had over a 150 feet of rode out and the catapult action after experiencing peak wind gusts of 90 some knots was something that I don't want to experience again.
Makes me think in an extreme chance id use my series drogue as a snubber. The drag would really slow down any catapulting...

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Old 11-08-2014, 06:36   #33
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Re: Snubbers - Or the Lack of Them

I grew up in the Navy. When I started cruising I anchored the same old way. I only heard about 'snubbers' when I got to the Caribbean. I never took to the idea.
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Old 11-08-2014, 09:51   #34
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Re: Snubbers - Or the Lack of Them

A nylon snubber doesn't have to be as strong as the chain (2 meters is not long enough though).

Let's assume a 10,000kg boat (21,000lb):

Let's say in a bad gust, when the cantenary runs out, the boat is moving at 10ft/sec. Technically, there is a small amount of elasticity in the chain. Say the chain stretches 1/2 an inch over 0.1 seconds. When you run the math, the chain and the attachment point take approximately 300,000newtons of force (approx 67,000lbs)

Now add in a 50' snubber that can stetch 5' over 0.5 seconds while bringing the boat to a stop and you will find the force is cut by a factor of 5 or approximately 60,000newtons (13,500lbs).

There are some complications that make the exact forces not quite the same but the principal holds true. The snubber greatly reduces the forces involved.
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Old 11-08-2014, 10:13   #35
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Re: Snubbers - Or the Lack of Them

My boat 51 foot. Weight 47,000lbs. 3/8th chain and 3/4 inch nylon snubber line about 50 foot long.

Normally run the snubber from the snig all the way back to the midships cleat on the stbd side. The snubber passes through about 12 feet of plastic tubing to prevent any chafe on the roller. Anchor is 110lb plow. I have ridden winds to 80 mph on this rig in good holding and I think it would have held in even more wind.

When on a hurricane mooring I usually run three similar lines to the mooring (1/2 inch chain to a large concrete block) and let them be about 50 foot long. I have been through three hurricanes on this rig without damage.
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Old 11-08-2014, 10:29   #36
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Re: Snubbers - Or the Lack of Them

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Hello

Don't You think that reliable chain stopper can be acceptable alternative to the line in this role? Just asking for Your opinion
NO Hell NO1 I did this in delivering my Brewer 12.8--it got dark in the tricky part of northern hawk channel--we couldn't find a snubber and were too tired to rig a dock line snubber -so we anchored and relied on the chain stopper.... WRONG! wind came up to 20+ and that made 6-7ft waves in the 12ft edge of the atlantic OW BAM!! POW BAm= heavy rain! . In the morning we saw the damage, Chain stopper ripped out bringing a 1ft sq. of deck with it----bow roller bent with roller dropped! I was hoping the windlass was--OK! It was! majorly only because windlass was not locked--and could give up a few feet everytime the chain straightened tight..BAM! WHAM! From now on its the new blue snubber--Rocna everytime that anchor goes down and wil continue to not lock the windlass-----oops forgot to tell about the anchor--it was one of these chromed CQR knowk -offs.Well we we pulled it up-the blades on each side had been sheared off-they had been welded! We now have a 55# roccna--and that chain stopper? its on the bottom along with the former chromed blades.
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Old 11-08-2014, 11:18   #37
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Re: Snubbers - Or the Lack of Them

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Yes, I'm with Dockhead here.

Snubbers are essential at times, non-essential at times and good insurance at other times. It isn't a case of one size fits all. A prudent skipper should be able to predicate the various instances of when and where to deploy a snubber. Also the size and length of same.

I used to have three snubbers ready to go - 2 ten metre "working snubbers" and a 2 metre "semi-snubber". The short one was really just a quick way of taking the load off the winch and transferring it to the samson post for short overnight stops in begin weather. It didn't perform a true snubber function. It wasn't used for daytime or lunch stop in similar begin weather. A "working snubber" was always used in significant weather, in exposed anchorages and so on. The other "working snubber" was a ready to go should the first fail. Like a cold standby radio .

However in my new (to me) untried cruising grounds with new (to me) weather systems and as yet unknown holding, the snubber will always be deployed until these is good reason not to!
Good post! We never use a long stretchy bouncy snubber, but,we do have a double 1.5'' nylon to chain claw to carry the load instead of the windlass or the chain stopper. We tried a long one once, and we were catapulted such that we went side on to the wind. That was the last time. I think Dockhead has the right attitude, DO whats RIGHT for the CONDITIONS
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Old 11-08-2014, 12:04   #38
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Re: Snubbers - Or the Lack of Them

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My rule doesn't actually apply to a largish snubber like that used with very small chain like that. The safe working loads and breaking strength are about the same. So you may ignore everything I've written, for your particular case!
Are you going to deploy and retrieve your snubber every time you back down on your anchor? Are you happy to have no backup in case your snubber chafes through? Why wouldn't you want to have some kind of chain stopper? Even a strop will do, if you don't feel like drilling into your deck.
I'm pretty sure my chain is 8mm... its at least 15 years old... must measure it next time back on board next week. Yes I do put the 'snubber ' on every time I back down on the anchor...12 inches of the snubber hooked on inboard of the roller ( I use a chain hook on the end of my snubber at all times... no rolling hitches or other non sense).
My rule says it works ... well it worked every other day for ten years in Patagonia.
No I wouldn't fit a chain stopper... don't see the need for one and my windlass is fitted that far forward ( standard production boat position) that there is no room for one anyway.
Chafe? I haven't had a chafe problem in 10 years but then I don't put it through the roller, I put it through a fairlead... renewed it two years ago just because I could.
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Old 11-08-2014, 12:15   #39
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Re: Snubbers - Or the Lack of Them

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What? You mean only in gentle places like the beagle channel, falklands etc... Interested in your 8mm chain, what grade and type? Obviously it's very well tested and suitable for your 39 footer. Got to get some chain for my new 40 footer, so thats why I ask. Cheers

By the way are you headed back to Aussie from Unzed?
Age and cunning... age and cunning..... thats what helps ensure you don't get caught in windy anchorages... I've been in a few but not many... worst was a strong easterly in Ushuaia on a friend's mooring, only time I have ever taken Stugeron in port

Pretty sure its 8mm... bought in Melbourne maybe 15 years ago... end for ended once, regalvanized once.

No plans to go on to Oz... 18 month refit and sailing in Unzud then back to Chile is the plan... assuming my wheels don't fall off in the meantime.
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Old 12-08-2014, 02:23   #40
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I'm pretty sure my chain is 8mm... its at least 15 years old... must measure it next time back on board next week. Yes I do put the 'snubber ' on every time I back down on the anchor...12 inches of the snubber hooked on inboard of the roller ( I use a chain hook on the end of my snubber at all times... no rolling hitches or other non sense).
My rule says it works ... well it worked every other day for ten years in Patagonia.
No I wouldn't fit a chain stopper... don't see the need for one and my windlass is fitted that far forward ( standard production boat position) that there is no room for one anyway.
Chafe? I haven't had a chafe problem in 10 years but then I don't put it through the roller, I put it through a fairlead... renewed it two years ago just because I could.
I don't really havr any right to preach to a guy who's been anchoring Patagonia for ten years

But . . . Why wouldn't you consider at least a strop to protect the windlass? A lot of things can go wrong with a snubber.
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Old 12-08-2014, 02:39   #41
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Re: Snubbers - Or the Lack of Them

I use a *snubber* as a sort of tell tale to confirm that the anchor has properly set. The snubber includes a heavy rubber mooring compensator... which with a few wraps of a 1" line. When the snubber sees sufficient force/load on it and the line on the compensator causes it to *unwind* a bit.. it tells me that the anchor has dug in and the forces on the boat is lifting the catanary and the anchor is not dragging....even slowly. When the wind pipes up or if I back down and the snubber does not unwind it means the anchor is dragging.

When I see the compensator unwind a bit I am confident that the anchor is set.

Of course the snubber also removed the forces from the vertical windlass to a dock cleat and takes the shock loads that can occur. In mild conditions the all chain rode does not need the snubber.
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Old 12-08-2014, 02:41   #42
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Re: Snubbers - Or the Lack of Them

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But . . . Why wouldn't you consider at least a strop to protect the windlass? A lot of things can go wrong with a snubber.
Well it hasn't yet.. ... main thing is to hang a big bight of chain below the chain hook so no chance of load coming on the chain and the chain hook/snubber falling off... don't ask how I found that out.

Re chain size... 8mm was the standard 'fit on all the Westerly Sealords and Oceanlords (39 and 41 foot, nominal 8 tonnes light displacement)... anything bigger wouldn't fit in the chain locker.

Given that most people would have some idea what depths they would normally anchor in why not just have a good appropriate length of heavy chain backed up by nylon rode? Always anchoring in about 10 metres? OK 30 metres chain and then a long length of nylon....
Hope that makes sense,.....
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Old 12-08-2014, 02:59   #43
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Re: Snubbers - Or the Lack of Them

Thorts re sailing around the anchor in a blow ( which may have some relevance in this discussion).
When I bought my boat she had a roller furling headsail.... no real windage aft... left to her own devices with no sail up the bow would pay off and she would wander off down wind .
Now she has all sorts of stuff down aft...wind gen... radar... other stuff... left to her own devices she will lie beam on to the wind.

Maybe the boats that sheer about in a blow have too much windage frd and could benefit from a bit more windage aft... same as the old steam drifters handled things when lying to their nets... I forget the name of that little sail they used... just a thought...
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Old 12-08-2014, 05:02   #44
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Re: Snubbers - Or the Lack of Them

By the way . . . . . several people have asked me about the durability of soft shackles in 'chain hook replacement mode' . . . . here is a photo of one I have been using for 2 years (including in some decent wind up in greenland). It's dirty but pretty much no chafe/wear (this is one of my earlier 'simple stronger' soft shackle designs).

Click image for larger version

Name:	<a title=photo.JPG Views: 117 Size: 147.0 KB ID: 86473" style="margin: 2px" />
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Old 12-08-2014, 08:27   #45
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Re: Snubbers - Or the Lack of Them

Glad to see that, since my spare/emeregency rode connects to the chain with a 1/2" soft shackle which, absent chafe, is the strongest link.

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