Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema? - Page 4 - SailNet Community
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post #31 of 44 Old 11-05-2019
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

for chafe gear other than commercially made, I've found that hydraulic hose cover sized for your line works well. Burn a small hole and attach a small line to secure it to your lines. Works well.
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post #32 of 44 Old 11-05-2019
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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Originally Posted by capta View Post
Then would you kindly explain why every single Maxi sailing vessel I've seen and been aboard worm, parcel and serve every shroud of Dynema standing rigging through the thimble to a point above deck that any sheet may touch, and some all the way? Seems like a whole lot of money spent to protect the Dyneema for no reason at all, according to you!
Thanks.
Because Dynema has very low *heat* resistance. Those maxi boats with their vertical pedestals and professional grinders move (for instance) the spin sheets *real* fast. If they're rubbing against a shroud as they do that, the shrouds (which aren't moving) get real toasty, then weaken, then the mast comes down. It's the same reason offshore racing rules don't allow for synthetic lifelines.

In a mooring pendant situation, stuff shouldn't be heating up that much.
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

You could also cut a short taper into the hose ends
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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According to the Dyneema people, Dyneema’s strength drops to 80% of original strength after 700 hours of UV exposure. https://dynamica-ropes.com/wp-conten...SM-Dyneema.pdf
Their chart does not show what the drop-off is after 700 hours, so it could drop to 3% after 701 hours - we don’t know. 700 hours is about two months of summer (12 hour) sunny days. Dyneema’s UV resistance may be better than some other plastic fibers, but UV rays still degrade its performance. I would not suggest using it for a mooring pennant.
Every plastic degrades in UV. I'm not sure, but lots of climbing resources claim the Dyneema is *more* UV resistant than nylon.
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

I read something today abour lifting slings used in the usa... 80% are nylon and 20% used are polyester.
In europe it is the opposite.
Poly is greater uv resist. Nylon is greater stretch.
Pick your properties...

Yeah, need to get a life...
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post #36 of 44 Old 11-05-2019
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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Originally Posted by jvlassak View Post
A couple of weeks ago, we had a sudden, but rather violent storm in the Boston area (winds up to 80 knots) that resulted in quite a few boats breaking loose from their moorings. Our boat snapped three pendants, including a longer 1 inch storm pendant. Fortunately she survived the storm, albeit with some damage. Now I'm trying to decide on new pendants for the mooring and I am considering two possible setups:

1) Two Yale Double Braid Maxi-Moor II Mooring Pendants, either 16 or 20 feet long

2) Two nylon pendants with Dyneema sections to minimize chafe at the chocks, something along the lines of New England Ropes Dyneema Cyclone Mooring Pendants. The nylon would provide some stretch to minimize shock loading.

Are there other options I should consider? Does anyone have experience with these systems? Is one setup significantly better than the other?

In addition, it seems that the standard scope on the moorings in our harbor is pretty small - about two to one I believe. Would increasing the length of bottom chain reduce the shock load on the pendants?

Thanks!
Hi, if you look at the mooring as a total package, the sum of all components, and use the correctly sized components for the job it should hold well. By this I mean a good weight appropriate to the boat size, a few metres of heavy stud link ships anchor chain (I use 38 mm), a couple of metres of good springer chain (I use 12 mm) to a good swivel if in a tidal flow, then the rope to the vessel, sized accordingly. Also remember that good well made splices count, the last few tucks tapered can make a difference.
This has been my experience however your results may vary.
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Cheers, Uncle Bob the 1st from Sydney Aust.
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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Originally Posted by Uncle Bob the 1st View Post
Hi, if you look at the mooring as a total package, the sum of all components, and use the correctly sized components for the job it should hold well. By this I mean a good weight appropriate to the boat size, a few metres of heavy stud link ships anchor chain (I use 38 mm), a couple of metres of good springer chain (I use 12 mm) to a good swivel if in a tidal flow, then the rope to the vessel, sized accordingly. Also remember that good well made splices count, the last few tucks tapered can make a difference.
This has been my experience however your results may vary.
I don’t have a mooring but sometimes attach myself to one.

In you post it’s all chain...but chain doesn’t flex. Taunt chain has no flex at all.

Also why the need for a swivel?


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post #38 of 44 Old 11-05-2019 Thread Starter
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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Originally Posted by Uncle Bob the 1st View Post
Hi, if you look at the mooring as a total package, the sum of all components, and use the correctly sized components for the job it should hold well. By this I mean a good weight appropriate to the boat size, a few metres of heavy stud link ships anchor chain (I use 38 mm), a couple of metres of good springer chain (I use 12 mm) to a good swivel if in a tidal flow, then the rope to the vessel, sized accordingly. Also remember that good well made splices count, the last few tucks tapered can make a difference.
This has been my experience however your results may vary.
I'm talking to the mooring company about how to make the mooring more robust. Their comment on the mooring requirements in Salem Harbor is that they're fine for normal conditions, but not for storms. I would never leave my boat in a storm on purpose, but I would definitely want my mooring to be designed to withstand a storm - i.e., upgrade bottom and top chain. My storm pendant had a tapered splice, but the transition point was probably still the weakest part of the pendant.


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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

Uncle Bob makes excellent points. A mooring has to be sized... ie every single component to the anticipated max load.

Begin by computing the windage (wind force) with the wind on the beam (boats do yaw).

You'll want a safety factor. 2,3, 4 or more times the wind load for the line, the shackles, the swivel the chain. and of course the mooring.

For normal conditions you will not need such heavy components. But since you can't change your mooring... get one for storm loads. What you can change is the line from the chain/float/ball to your cleats. This can be designed for storm loads and used in hurricane season.

Better safe than sorry. Engineering design always includes a "factor of safety".

pay attention... someone's life depends on it
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Re: Mooring pendants - Yale Double Braid Maxi-Moor or Dyneema?

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Originally Posted by SanderO View Post
Uncle Bob makes excellent points. A mooring has to be sized... ie every single component to the anticipated max load.

Begin by computing the windage (wind force) with the wind on the beam (boats do yaw).

You'll want a safety factor. 2,3, 4 or more times the wind load for the line, the shackles, the swivel the chain. and of course the mooring.

For normal conditions you will not need such heavy components. But since you can't change your mooring... get one for storm loads. What you can change is the line from the chain/float/ball to your cleats. This can be designed for storm loads and used in hurricane season.

Better safe than sorry. Engineering design always includes a "factor of safety".
Fully agree, but I now realize that the requirements for the moorings in our harbor may be a limitation - scope is very limited for instance and there is also a limitation on the length of the pendants


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