Snubber

Was talking with a good friend today about my current snubber setup which is adequate at best. Anyways I plan on having one made, but was wondering for my 90,000lb+ boat what diameter should I use? My friend said 3/4 should be fine but it's always nice to hear second opinions. Going to be made out of 3 strand polyester or nylon.

N4712 said:

Was talking with a good friend today about my current snubber setup which is adequate at best. Anyways I plan on having one made, but was wondering for my 90,000lb+ boat what diameter should I use? My friend said 3/4 should be fine but it's always nice to hear second opinions. Going to be made out of 3 strand polyester or nylon.

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5/8 would be more in line. I have used 5/8 for Delfin, who weighs 135,000# and now use 3/4 only because my setup includes a rubber snubber that provides the stretch the 5/8 would have.

Smaller line has more stretch so I'd say nix on 3/4.

If its stretch and snubbing you want I would go with half inch the longer the better. If proximal chain hangs down into water that is good and its weight will increase the snubbing effect and help with the catenary angle. I have seen many short rope snubbers and I think they may quite the chain but do little to diminish the shock loads.

I've got a snubber ... 435' long.

Talk to the people at Rope Inc.

If you want strength and stretch, add in one or two of those rubber mooring line snubbers Taylor makes.

I use a chain hook plate of sorts. My snubbers are attached by shackles. Have 2 sets of ropes, 1/2" and 3/4". Takes very little to switch, and options relative to conditions are always good.

Ted

I have to say 3/4 is most appropriate for your need. 3/4 3 strand is approx 16000lbs breaking strength - 5/8 is approx 12000. In a bit of a blow with some wave action added in you could easily see 2-4000lbs loading. 3/4 puts you in the right range.

Ken

kchace said:

I have to say 3/4 is most appropriate for your need. 3/4 3 strand is approx 16000lbs breaking strength - 5/8 is approx 12000. In a bit of a blow with some wave action added in you could easily see 2-4000lbs loading. 3/4 puts you in the right range.

Ken

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If I were picking an anchor rode or considering a really strong blow the larger diameter rode makes sense. For daily use in calmer conditions I still prefer a light long line and would carry more than one size. If a snubber brakes the chain is still there and a replacement can be hooked on and let out. If conditions are such that you need a snubber you will know when it breaks . The lighter line will do a better job and if combined with rubber snubbers even better.

A snub line is not an anchor rode. It is supposed to be undersized to the main rode in order to introduce stretch. The longer the distance over which the vessel can move to dissipate the impact of wind and wave, the lower the forces acting on the primary rode will be. The common strategy is to use a snub line that will stretch a few feet before the load is taken up by the primary rode. The two shouldn't be confused.

Delfin said:

A snub line is not an anchor rode. It is supposed to be undersized to the main rode in order to introduce stretch. The longer the distance over which the vessel can move to dissipate the impact of wind and wave, the lower the forces acting on the primary rode will be. The common strategy is to use a snub line that will stretch a few feet before the load is taken up by the primary rode. The two shouldn't be confused.

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I agree. However, with an all chain rode (as I have), I would want the snubber to prevent the huge shock loads that would occur if the wind/waves rose enough to cause loss of catenary in the chain. At that point, the snubber would be under very heavy load. Under mild conditions, I wouldn't really need a snubber except to keep loads out of the windlass.

There is a very good article that touches on my concerns - if you google "Anchor Math and Management Part 1"

Ken

Just curious...do nylon rope manufacturers rate the strength of their ropes based on testing dry rope, or do they account for the approximately 15% loss in strength when nylon rope gets wet?

kchace said:

However, with an all chain rode (as I have), I would want the snubber to prevent the huge shock loads that would occur if the wind/waves rose enough to cause loss of catenary in the chain.

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The only reason to use a snubber is with all chain rode. A combination rode is its own "snubber."

A properly designed and deployed snubber is there to protect against the shock loads you speak of. But the only way it can do this is if it has sufficient stretch to absorb the shock. Too thick of a snubber line or lines and it won't provide the desired protection.

If the situation gets nasty enough to threaten the integrity of the snubber it's probably time to take some other action. Like leave.

Marin said:

If the situation gets nasty enough to threaten the integrity of the snubber it's probably time to take some other action. Like leave.

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The problem I have always found is to anticipate when that situation may arise and react prior to all hell breaking loose.

Andy G said:

The problem I have always found is to anticipate when that situation may arise and react prior to all hell breaking loose.

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We've had that situation arise and our solution was..... leave. We started the engines and my wife kept us off the lee shore while I hauled up the anchor. As it was 3:00 am or so and dark we elected to run an oval holding patters (pilot experience kicking in I guess) in the portion of the bay that was less violent until daylight arrived. We set up the holding pattern using the plotter and radar.

The reason we did not want to leave the bay is that there were a lot of commercial crab pot floats across the eintrance and we did not want to take chance of snagging one in the dark. We also could not see the conditions outside the bay,

So we took turns for the next three hours running our holding pattern, and then when daylight arrived we determined whether to follow Plan A or Plan B and then carried it out.

We always do a "what will we do if x happens" planning session when we anchor somewhere. We try to have at least a Plan A for the situations we think could arise, even if they are not forecast to. Sometimes we can come up with a Plan B and even a Plan C. What we don't want to do is have to figure all this out when the forecasts prove to be wrong and we're actually in the situation we need to get out of.

It's an easy thing to plan out, just takes a few minutes, we jot down the plans, and tape the note to the upper helm cable chase at the front of the main cabin.

To follow up on this, i ended up ordering a 3/4 Three strand with a chain hook. That's the new setup, I've talked to owners that have used the above setup successfully many times.

Greetings,
Mr. 4712. 3/4". Do you think that's too heavy. What's your boat weigh?

We're about 90k lbs. I think it's fine.

N4712 said:

We're about 90k lbs. I think it's fine.

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Which hook did you invest in?

Sent from my Nexus 4 using Trawler

mbevins said:

Which hook did you invest in?

Sent from my Nexus 4 using Trawler

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Good ole fashioned chain hook.

You only talk about diameter of the line, not the length. If it is a short line it will be unable to stretch. There are lots of vessels about with 6' snubbers, these are fine for taking the load off the windlass and stopping the chain rattling on the bow roller - but as a device to absorb shacks - basically a waste of time. You need around 30' to be of value and on a trawler with plenty of beam I'd be using 2, one each side. This will not halve the load but will reduce veering and each 'side' will take near the full load half the time. Its the veering that induces the shock loads, so any reduction will reduce the severity of the shock loads.

Snubbers should be considered consumables, so having the load each side will double the life (though there are no savings as you need 2!) Join them to a common chain hook. if your snubbers do not break at around 18 months 2.5 years - they are too big! (or you need to get out more

I'd say at 3/4" you are too big, but it will be good for winds over 35 knots, or thereabouts, but will be too inelastic at 25 knots to 35 knots. The ideal is to have 2 sets of snubbers, something for everyday use and something with a bit more muscle for times when you wish you had bought the better anchor

Tests were conducted on those Taylor Made rubber snubbers - waste of money. Size for size - you would need 5 rubber snubbers to absorb the snatch that a 30' piece of nylon can absorb, and I know which is cheapest and easier to use .


edit: There is an article in the Nov 2013 issue of Practical Sailor that looks at nylon, 3 strand, multi plait and climbing rope and Taylor Made type snubbers with some calculations. close edit

DJ: In total it's 40ft in length.

N4712 said:

DJ: In total it's 40ft in length.

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Magic

You really do not need, want, 40' of nylon stretched out of the bow - attach to a stern cleat, or amidships cleat, run up the side deck and have just a short length (beyond a fairlead or bow roller) actually attached to the chain. You will have abrasion points, the fairlead etc, so use something to protect against chafe.

If you have lots of snubber forward of the bow it will be in the sea, collecting sand and mud (which will increase wear) and if it is such it can contact the seabed then conventional chain hooks have propensity to fall off. Keeping the 'beyond bow length' short means it will never touch the seabed (or not intentionally)

Each installation is very vessel specific so I can only generalise.

But I strongly suggest, if you have a beamy vessel - go for the bridle.

Djbangi said:

Magic



You really do not need, want, 40' of nylon stretched out of the bow - attach to a stern cleat, or amidships cleat, run up the side deck and have just a short length (beyond a fairlead or bow roller) actually attached to the chain. You will have abrasion points, the fairlead etc, so use something to protect against chafe.



If you have lots of snubber forward of the bow it will be in the sea, collecting sand and mud (which will increase wear) and if it is such it can contact the seabed then conventional chain hooks have propensity to fall off. Keeping the 'beyond bow length' short means it will never touch the seabed (or not intentionally)



Each installation is very vessel specific so I can only generalise.



But I strongly suggest, if you have a beamy vessel - go for the bridle.

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Thanks for the tips, like I've said I've talk to multiple people that have used this setup successfully. So I don't think I'm going to change one bit of it. The night of chain will keep the hook on the chain.

N4712 said:

Thanks for the tips, like I've said I've talk to multiple people that have used this setup successfully. So I don't think I'm going to change one bit of it. The night of chain will keep the hook on the chain.

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Oliver
I tried using the standard chain hook with not much success. I switch to the Mantis chain hook, and has been very pleased your results may vary.

I have used metal hooks of different types and my conclusion 1/2 inch rode with a good rolling hitch is just fine. Less to break or distort goes on easy and stays there until you remove it. No hidden stress cracks to give in the middle of the night. cheap actually free.

N4712 said:

Good ole fashioned chain hook.
View attachment 36778

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That's what I also use and I have never had it come off when under use.
It's also easy for me t pluck off as it gets to the pulpit.

N4712 said:

Thanks for the tips, like I've said I've talk to multiple people that have used this setup successfully. So I don't think I'm going to change one bit of it. .

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I think your plan is fine. I also use a single line and a standard chain hook.

jleonard said:

I think your plan is fine. I also use a single line and a standard chain hook.

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Thanks, as long as there's a good bight of chain i don't see how i can have a problem.

Because of my combo rode, I rarely need the snubber unless the waters are very shallow and the anchorage is tight with friends' boats. On the few occasions I need a snubber, I use a chain hook, too. Like Richard, I've never had it fall off. As you say, it's all about the proper rigging.

The artist who painted my boat in my avatar picture took it from an early morning picture taken at anchor by Giggitoni with the snubber in place. She accurately captured the bight as well as the deck chairs left on the foredeck from the previous night's stargazing. The only problem is that she swapped the chain for the snubber so links of chain show where there is actually snubber and vice versa.