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Old 12-19-2014, 04:27 PM   #1
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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.
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Old 12-19-2014, 05:23 PM   #2
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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.
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.
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Old 12-19-2014, 07:19 PM   #3
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Smaller line has more stretch so I'd say nix on 3/4.
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Old 12-19-2014, 08:06 PM   #4
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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.
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Old 12-19-2014, 09:32 PM   #5
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I've got a snubber ... 435' long.
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Old 12-19-2014, 09:53 PM   #6
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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.
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Old 12-19-2014, 10:01 PM   #7
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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.

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Old 12-22-2014, 01:20 PM   #8
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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.

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Old 12-22-2014, 01:46 PM   #9
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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.

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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.
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Old 12-22-2014, 01:51 PM   #10
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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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Old 12-22-2014, 03:09 PM   #11
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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.
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"

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Old 12-23-2014, 01:15 AM   #12
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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?
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Old 12-23-2014, 03:25 AM   #13
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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.
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.
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Old 12-23-2014, 07:07 AM   #14
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If the situation gets nasty enough to threaten the integrity of the snubber it's probably time to take some other action. Like leave.

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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Old 12-23-2014, 03:30 PM   #15
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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.
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.
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Old 01-23-2015, 12:38 PM   #16
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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.
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Old 01-23-2015, 12:42 PM   #17
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Greetings,
Mr. 4712. 3/4". Do you think that's too heavy. What's your boat weigh?
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Old 01-23-2015, 01:29 PM   #18
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We're about 90k lbs. I think it's fine.
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Old 01-23-2015, 09:42 PM   #19
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We're about 90k lbs. I think it's fine.
Which hook did you invest in?

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Old 01-23-2015, 10:19 PM   #20
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Which hook did you invest in?

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Good ole fashioned chain hook.
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