Bridal size

[ebisucapt]

Looking for a recommendation for the size of the bridal. I have been told that mine at 1" is way to big and will not provide enough stretch. My Cat weighed in at just under 18,000lbs. I am getting ready to buy new line for the bridal and docking lines. 5/8" three strand nylon has a breaking strength of only 9,000 so seems a bit small to small to me. 3/4" is up there at 11,300. But these breaking strength's sure seem to vary from manufacturer to manufacturer. And these were the most expensive and strongest I seen.
Greg

[chris mac]

Our cat weighs in close to yours. It came with a 5/8 bridle that has held us very well in several 40+knot blows.
I did buy a back up bridle from mantus and I think it is 3/4" but havent used it so can't offer any comparison.
You dont need a breaking strength of boat weight, you aren't lifting it. Have it close to or slightly less than your chain breaking strength

[LittleWing77]

I think you may mean "bridle"... or are you marrying your boat?

[Chotu]

I like mine petite. Thin and in shape. �� lol

[thinwater]

5/8" is about right, some would say even too fat, but that depends on more variables. I used 4-6000 pound breaking strength bridles on my 9000-pound cat. I would not have wanted anything fatter.



Remember a bridle is NOT permanent gear, it is a disposable shock absorber that is mean to be replaced when it looses its stretch, probably after a few hundred nights, depending on the weather. Keep it simple and plan on regular replacement. If you don't like splicing, a pair of dock lines works nicely.


Length matters. The legs should be greater than the beam. Some secure them to the midships (me) or stern cleats to get more length for stretch and an easy way to increase scope in a blow, although that does require attention to chafe.

[Tin Tin]

Find the weakest link in your anchor set up, probably the anchor or bridle shackle. then get nylon bridle line that is slightly stronger. The bridle forces are divided by two and if you are splicing with ss eyes you will not lose much strength as opposed to knots. Bridles do get a bit of wear and tear from chafe and UV so going a couple of sizes bigger will mean in a few years that line is still up to spec.

[thinwater]

Originally Posted by Tin Tin

Find the weakest link in your anchor set up, probably the anchor or bridle shackle. then get nylon bridle line that is slightly stronger. The bridle forces are divided by two and if you are splicing with ss eyes you will not lose much strength as opposed to knots. Bridles do get a bit of wear and tear from chafe and UV so going a couple of sizes bigger will mean in a few years that line is still up to spec.

Yes... and no.


The force on the legs is actually divided only by about 1.2 for two reasons:

• The boat yaws with the wind gusts. This can place most of the load on one leg.
• The angle itself increases loading.

The anchor-to-chain shackle should be the same strength as the chain. But I don't think that is what was meant.


There are a number of bridle-to-snubber attachment methods that are as strong as the chain, but other than Wichard hooks, failures are rare. Personally, for catamaran bridles I like either a bridle plate, Dyneema sling prusik hitch, or soft shackle. The best choice often depends on how it is deployed, which is quite variable on cats.



Bridle legs can actually be substantially weaker than the chain, normally 20-40% less. There are two reasons:

• The bridle is disposable. It will not be on the boat nearly as long as the chain.
• The chain is ALSO secured with a chain lock. If the bridle fails, slap on a fresh one.

Thus, the bridle legs are no larger than the recommended rope rode size for the boat, and generally one size smaller. That should make basic, obvious sense, since there are two.


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For a permanent mooring you will go larger, and there are other concerns.

[Perfect Ride]

Originally Posted by thinwater

Length matters. The legs should be greater than the beam. Some secure them to the midships (me) or stern cleats to get more length for stretch and an easy way to increase scope in a blow, although that does require attention to chafe.

Important note, also pay attention to the gear on your points of attachment.

If in coral or rocky bottoms fire hose or other covering at the rode end can extend life if bridle is longer than your depth.