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Old 11-27-2014, 06:52 AM   #1
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What size bridle?

Pretty good chance one of these will be under the tree this year.



They're offered in 3 rope sizes (5/8, 3/4 and 1 inch) and I need to specify one to Santa. My Defever 44 is about 44,000 lbs. I can't imagine why I'd use anything smaller than the 1 inch bridle even though Mantus says the 3/4" is good enough for a 40-50 ft vessel. Seems like I'd want the largest I can get for strong wind surge. For "normal" anchoring, it seems I'd still get the benefits of moderate shock load protection with the 1 inch; I'd just be dealing with a larger than necessary bridle. I certainly don't want to buy 2 for different conditions unless I'm missing something.
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Old 11-27-2014, 07:01 AM   #2
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Bigger isn't necessarily better as you want some stretch in the snubber.

I would go with the 3/4 then, actually I think that is a bit heavy...I would look to some sort of add on stretch device.

Chafe is the enemy and once the snubber is used in a big blow, it should be replaced as the nylon if that is used is usually compromised. Ideally, you use something like 1 inch through the chocks for chafe (with chafe protection), and something with a working load near but slightly above the working load of the chain.

Lots of theories , all have pluses and minuses.
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Old 11-27-2014, 07:57 AM   #3
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I have the 3/4 inch bridal for our 58000 lbs boat. It works great. I totally trust it in any type of a storm blow. Would I use it in a hurricane where you have large sustained winds for up to a day or so. Not if I could ever help it. In this situation I always try to have the boat hauled. But then I would not trust anything else either in that situation. anchors, other boats, other boats, other boats.....
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Old 11-27-2014, 09:14 AM   #4
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I use 3/4 but the bridle is in two separate pieces, both of which shackle to the mantus chain hook. This effectively doubles the working strength of a rode which is spliced prior to the eye as it appears to be in the picture.
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Old 11-27-2014, 11:21 AM   #5
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Originally Posted by angus99 View Post
Pretty good chance one of these will be under the tree this year.



They're offered in 3 rope sizes (5/8, 3/4 and 1 inch) and I need to specify one to Santa. My Defever 44 is about 44,000 lbs. I can't imagine why I'd use anything smaller than the 1 inch bridle even though Mantus says the 3/4" is good enough for a 40-50 ft vessel. Seems like I'd want the largest I can get for strong wind surge. For "normal" anchoring, it seems I'd still get the benefits of moderate shock load protection with the 1 inch; I'd just be dealing with a larger than necessary bridle. I certainly don't want to buy 2 for different conditions unless I'm missing something.
There are two purposes for a snubber. The first is dampening chain noise and the second is reducing strain on the whole system in a serious blow by inducing stretch. You can get the first with any size line, but the second is a function of the windage and mass of the boat. Your vessel would probably do fine with a 1/2" line.

Delfin weighs 65 tons, and our solution is probably overkill, but seems to make sense to me.

We used a 5/8" 3 strand dacron for a snub line for 5 years, but a couple of years ago I built a line that starts with 3/8" Amsteel to secure the line to the strong point, attached to 3/4" octoplait that has a breaking strength equal to the 1/2" chain, coupled to an Ultra rubber snubber. The idea is that the rubber snubber gives the kind of stretch you would get from 1/2" 3 strand for normal loads, but once it really starts blowing, the 20% stretch before breaking of the 3/4" octoplait kicks in. The bight of chain that you would lay out over the snub line would be equal to that stretch before breaking. Since our rig is around 25' long, that is around 6'. At that point of stretch you are relying on the chain.

Attaching the snub line to the chain with a hook from any manufacturer doesn't make a lot of sense to me since they will fail long before the snub line will. I prefer to use a soft shackle made of Amsteel or Plasma which is stronger than the chain.
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Old 11-27-2014, 01:35 PM   #6
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It would seem to me that the size of the bridle would be the same as is adequate for a non chain rode on any given size boat.
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Old 11-27-2014, 02:57 PM   #7
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We made our V-bridle from two lengths of half-inch nylon, a chain grabber plate, two shackles and two karabiners. We had the local fisheries supply house put a thimballed eye splice in one end of each of the nylon lines, put a karabiner on each thimble, and put the shackles in the corner holes of the chain grabber.

We assemble the snubber just prior to anchoring by snapping the karabiners to the the shackles.

The half-inch nylon provides good shock-absorbing for our 30,000 pound boat. Any heavier line and the shock absorbing would be insufficient.

In practice, once the anchor is deployed, the rode paid out, and the anchor set, we attach the chain grabber and then let the all-chain rode out until the grabber is some eight to ten feet below the surface of the water. We cleat off the bitter ends of the bridle lines to separate deck cleats, and then let more chain out until there is a loop about ten or fifteen feet long hanging below the chain grabber on the boat side.

The low position of the grabber and the long loop of chain between it and the boat lowers the angle of pull on the anchor, acts as a sort of kellet as the wind picks up to help keep the angle a little lower than if the loop wasn't there, and prevents all movement of the chain in the bow roller, which isn't a problem other than the noise transmits itself all through the boat.
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Old 11-27-2014, 03:29 PM   #8
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It would seem to me that the size of the bridle would be the same as is adequate for a non chain rode on any given size boat.
Not really. What you are looking for is stretch. The thicker the line, the less stretch. If you look at the physical forces on the ground tackle, the critical variable is the distance over which the force is absorbed. If it has to be absorbed on a distance of 2 feet, the force is four times greater than that if it is absorbed over 4 feet and 32 times greater than if it is absorbed over 8 feet.
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Old 11-27-2014, 03:55 PM   #9
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Ah so learn something new everyday. Thanks
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Old 11-28-2014, 06:39 AM   #10
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For "normal" anchoring, it seems I'd still get the benefits of moderate shock load protection with the 1 inch;

Nylon does not offer stretch for shock absorbing till about 10% to 15% if the rated load is applied.
Most anchorages will give o-nite loads well under 10% of the lines breaking strength.

For a smoother ride a snuber of very thin , 3/8 or so is required to allow movement in small winds as the boat surges or sheers.
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Old 11-28-2014, 09:30 PM   #11
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Since we switched over to an all chain rode this summer a bridal is also on my list. I've been trying to determine an appropriate length. I see here that you settle the connection plate under water? That means a length of 15' or so? My bow is about 7' off the water.

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Old 11-28-2014, 09:38 PM   #12
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Since we switched over to an all chain rode this summer a bridal is also on my list. I've been trying to determine an appropriate length. I see here that you settle the connection plate under water? That means a length of 15' or so? My bow is about 7' off the water.

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The height of the bow above the water doesn't really matter. I'd go for around 30' and use a soft shackle to attach the snub line to the chain. Much stronger.
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Old 11-28-2014, 11:13 PM   #13
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Since we switched over to an all chain rode this summer a bridal is also on my list. I've been trying to determine an appropriate length.
The lines that make up our V-bridle are each 25 feet long.
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Old 11-29-2014, 12:23 AM   #14
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I put together a bridle like the one Marin described. However, I've noticed that most other boaters lower the chain grabber to the water level, not below it. This reduces the angle of the rode, eliminating the distance from the bow to the water in the scope calculation. What do others do: chain grabber at the water or below it?
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Old 11-29-2014, 07:34 AM   #15
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For storms , that are well forecast a different technique might be required.

WE use a heavy 1 inch storm line , but to bring it on board it is connected to a 1/2 inch chain that goes around a strong bollard.

Most boats seem to be lost when the anchor line or bridal is chafed thru ,
1/2 inch chain may eat some boat if the padding is lost , but it wont simply wear thru.

Compared to nylon, chain is very weak, so monster chain like 1/2in or larger is required.
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Old 11-29-2014, 08:55 AM   #16
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Chain grabber at water level. In a blow the chain grabber is out of the water.
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Old 11-29-2014, 09:19 AM   #17
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I put together a bridle like the one Marin described. However, I've noticed that most other boaters lower the chain grabber to the water level, not below it. This reduces the angle of the rode, eliminating the distance from the bow to the water in the scope calculation. What do others do: chain grabber at the water or below it?
I don't understand how having the chain grabber at water level changes scope calculation. When the wind is up and the chain is bar tight, isn't the rode angle essentially unchanged with or without a bridle? (And assuming no bow eye near water level?)
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Old 11-29-2014, 09:21 AM   #18
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The height of the bow above the water doesn't really matter. I'd go for around 30' ....
Or longer. For day to day you can shorten it up if you like. For heavy weather use the full length. In a blow, the longer the snubber, the more stretch/elasticity and the less shock loading on the anchor/boat.
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Old 11-29-2014, 11:08 AM   #19
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Chain grabber at water level but I lower it in a blow to prevent in catching on the pitching bow pulpit (in theory)
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Old 11-29-2014, 11:23 AM   #20
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Or longer. For day to day you can shorten it up if you like. For heavy weather use the full length. In a blow, the longer the snubber, the more stretch/elasticity and the less shock loading on the anchor/boat.
Which is the critical point most seem to miss. Again, if all you want is quieting of the chain, any length of snub line will do as long as it clears the roller. If what you are looking for is stretch to reduce loading on the ground tackle, then 8 feet of snub line is a whole lot less effective than 30' or 50' as you suggest, and a thinner snub will be more effective than a thicker one. It is all about stretch.

And I am still puzzled why someone would want a strong snub line and then attach it to the chain with a hook that is half as strong as the snub...
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