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Old 06-06-2014, 09:02   #1
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Bridle for Spinnaker Pole

I'm thinking about adding a bridle to our spinnaker pole. For simplicity, I'd like to use dynema line with assorted brummel eye splices. Two questions,
1) Should I add a metal ring in the middle or just splice a larger eye?
2) Any way to splice the dynema on both ends of the pole?

I can do a brummel on one end of the pole but not the other. I don't think a metal ring would fit through and the one-ended mobeus splice doesn't seem to lace through the ring/pole.

Any tricks to splice a single line to both ends of the pole - or - am I going to have to tie a bowline as the final end?

Thanks, Don
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Old 06-06-2014, 16:23   #2
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Re: Bridle for spinnaker pole

Just get rid of the brummels and use a lock stitched eye splice. They make this a lot easier, and there is no real reason not to.

The center defiantly needs a metal eye as a place to attach the topping lift to. There are a number of ways to do it, but simply eye slicing it in the middle of two lines is the easiest.
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Old 06-06-2014, 16:37   #3
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Re: Bridle for spinnaker pole

Quote:
Originally Posted by Stumble View Post
Just get rid of the brummels and use a lock stitched eye splice. They make this a lot easier, and there is no real reason not to.

The center defiantly needs a metal eye as a place to attach the topping lift to. There are a number of ways to do it, but simply eye slicing it in the middle of two lines is the easiest.
I completely agree with this advice. The Brummel is needlessly complicated, and the lock stitched splice, according to Sampson, is equally strong.

If you don't want to "waste" a lot of expensive Dyneema making two extra eye splices, as per Stumbles suggestion for inserting the O-ring, simply seizing it in place will likely work fine. A wracking seizing plus a couple of stitches will keep it from sliding along the bridle and have plenty of strength.

Cheers,

Jim
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Old 06-06-2014, 16:53   #4
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Re: Bridle for spinnaker pole

Jim, you are talking about an extra foot of 1/8" dyneema. That's like $2. Seizing is probably fine, but I wouldn't mess with it. The possible loss of strength is to high compared to the gain.
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Old 06-06-2014, 16:55   #5
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Re: Bridle for spinnaker pole

" a wracking seizing plus a couple of stitches " ?

I'm pretty sure I had one of those last Thursday morning. They are no fun at all.

Maybe it was the tequila.
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Old 06-06-2014, 17:14   #6
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Re: Bridle for spinnaker pole

I can't believe I never thought of this, but I have a new idea for an amsteel bridle... I need to make one up to test it, but give me a day or so and I may have an even better idea of how to make them.

My advice above still stands, but the new idea would eliminate the bridle mess on the fordeck and make the bridle self stowing.
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Old 08-06-2014, 13:49   #7
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Re: Bridle for spinnaker pole

I'm OK with spiced eyes on the ring and then the lock-stitch - that will work fine.

Stumble - I look forward to your "new idea"!!! There are other discussions where people bury a bit of elastic cord, so the bridle stays tight when stored. Is that what you are thinking?

Thanks everyone for this discussion,

Don
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Old 08-06-2014, 15:15   #8
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Re: Bridle for spinnaker pole

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Originally Posted by Capt.Don View Post
I'm OK with spiced eyes on the ring and then the lock-stitch - that will work fine.

Stumble - I look forward to your "new idea"!!! There are other discussions where people bury a bit of elastic cord, so the bridle stays tight when stored. Is that what you are thinking?

Thanks everyone for this discussion,

Don
Basically, but I gave up on the buried bungie cord since it never really worked well and the bungee always broke. Plus I don't like the way it opened up the braid of the amsteel. It always looked messy to me.

While I was typing the above answers something came to me. Unfortunately it seems I won't be able to get to it this week, so here goes.

Instead of using a leingth of amsteel with an eye splice at each end (one to the jaws the other to the ring) make up a whoopie sling. If you aren't familure with them it's an eye splice on one end, and the other end is a sliding eye. With the bury being brought out of the standing line and a knot put in the end. These are tested at 80% of line strength by Sampson btw. Then splice a piece of bungee onto the end of the adjustable tail.

This way the bungee pulls the whoopie sling tight when not in use, but when deployed puts the whole leingth of the bridle out.

My concern is if there is enough leingth to allow a 45 degree bridle, while allowing for enough bungee to snug it up when it's stored. Otherwise just the whoopie slings would work, but leave a tail of line on the deck which would be nice to avoid.
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Old 08-06-2014, 15:35   #9
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Re: Bridle for spinnaker pole

Greg,
Interesting idea,
, then just an exposed bungee to keep all neat and tight.
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Old 08-06-2014, 16:14   #10
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Re: Bridle for spinnaker pole

Exactly.

I would probably hog ring the bungie onto the eye on one side, and burry on the handle side with a lock stitch.

It does mean both sides will have two legs, which is a little annoying, but better than the buried bungie which never really worked for me. It was fine when installed but either slipped or the bungie failed quickly.
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Old 08-06-2014, 16:27   #11
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Re: Bridle for spinnaker pole

Greg, I know you mentioned the center rings - I've seen several other posts on the web claiming you can just use an eye in the amsteel. I'm leaning this way and not using the rings, at least for my first version. Then when stored, I don't have the metal rings banging around.

Opinions on the bridle angle vary from 30-45 degrees, and I've also seen a post on Brian Toss's forum recommend 15% of the length, which would be 16.7 degrees. My eyeballing the height of the bridle, is about this - I was thinking 2' on our 14' pole.

I'm starting to soft-shackles, so I'm Ok with connecting lines, rings, cleats.... with this type of line.
Don
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Old 08-06-2014, 16:48   #12
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Re: Bridle for spinnaker pole

Don,

The larger the angle the less compression load on the pole. It really depends on the pole then how much load it can take. Ideally then the forward end of the bridle would be directly in line with the topping lift, which would allow minimal compression loads, but at the extent of a really long bridle. So a compromise is reached and you make the best of it. I like 45 degrees, but then I also use a very small spinnaker pole on big chutes, so I need to be more conservative. If you are using a large pole then you can get away with shorter bridles. Of course this gets a little academic if the bridle is adjustable in length since the storage problem becomes, well less of a problem.

I frankly wouldn't get rid of the metal ring no matter what. There is something to be said for the ease of finding it in the dark by feel alone, the fact it never collapses on itself, and the weight isn't a big issue. I see the advantage of using soft shackles (I use them pretty much everywhere) but this is one of those things I think the metal has advantages rope can't. If I was going with just a loop in the Amsteel, I would probably do an eye splice to a Y bridle (like on asymmetric spinnaker sheets) so that the eye is easier to find. Of the soft loop versions this is my favorite, but I wouldn't use it for what it's worth.

The upside is attaching some shock cord to this for storage would be almost too easy.
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Old 08-06-2014, 16:53   #13
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Re: Bridle for spinnaker pole

Don, don't overthink this bit of kit! I don't think that the length is very critical, and your eyeball estimate should work just fine. Further, I think that splicing a loop into the center instead of a s/s ring should be a good application as well. And finally, having some sort of bungie retractor is, IMO, an unnecessary complication for a simple lifting bridle.

We have been using single ended poles for many years, but back when I did end-for-end gybes a simple bit of wire with a ring in the center worked quite well to hold the pole up. I can't remember if its included angle was 16.7 degrees or 17.3 degrees... or was it 21.2 degrees??

This Dyneema line is wonderful stuff, and folks keep inventing new uses for it. The spinny pole bridle is a great application.

Cheers,

Jim

Edit: Since reading Greg's latest post, I have to ask if he really thinks that the compression loads from the lift bridle represent a significant challenge to the pole? Compared to the sail loads, they are surely vanishingly small, aren't they?
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Old 08-06-2014, 21:56   #14
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Re: Bridle for Spinnaker Pole

Jim,

Like most things it depends. If you are using a normal size pole for your boat then anything around 30 degrees or so will likely be fine. I don't. I used a 2" pole on a 760sqft spinnaker. This is the same pole size as a J-22 spinnaker (325sqft). To do this required adding a longer bridle to keep the pole from visibly flexing.

The downside of a long bridle is that you get a lot of extra deck clutter. But it does make the system stronger. If using bungie cord allows you to clear the deck of the longer bridle, then you effectively get a stronger system for the cost of a little bungie cord. Wether it is necessary or not just depends on how heavily loaded the pole will be.


The highest loads exerted by the bridle are not from the topping lift, but from the down haul while power reaching. As you mentioned this is also when the sheet loads are the highest. Which is just when it's most important to reduce the load anywhere you can.
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