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Old 06-06-2007, 08:27   #1
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Main Halyard - Snap Shackle??

Current attachment has me tying a bowline - works but is sometimes a pain. I always remove the halyard when docked so as to avoid slapping the mast and annoying my neighbors.

I was thinking that a high-strength snap shackle would work, but how do I calculate what strength I will need? Main sail is 468 square feet, fully-battened big boy....

Would a heavy (7,000lb) Nicro snap shackle be suitable or am I just asking for trouble?

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Old 06-06-2007, 09:38   #2
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my halyard has a spliced eye connected to a shackle and secured with a split ring. No chance of coming loose. I would be scared of anything else some how releasing
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Old 06-06-2007, 09:51   #3
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Product made for the job.

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and you can use lock wire to secure the shackle pin if you're that worried about it. I never have.

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Old 06-06-2007, 10:28   #4
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Splicing is always better for a number of reasons. I used a metal eye insert in my splice and just a regular shackle.
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Old 06-06-2007, 10:34   #5
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I would not use a snap shackle. Use a double thread shackle. If you don't replace the halyard you'll have to use a bowline on the shackle as you won't be able to splice old double braid.
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Old 06-06-2007, 10:36   #6
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Quote:
Originally Posted by cal40john
Product made for the job.

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and you can use lock wire to secure the shackle pin if you're that worried about it. I never have.

John
Go with this or the appropiate locking D-shackle. It is what I have used and it has not let me down.
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Old 06-06-2007, 10:53   #7
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Why don't you stick with the Bowline. 1. It doesn't have a potential lethal weapon hanging on the end of a swinging pendulum if it should ever get loose. 2. You can end for end or cut off a little of the line to shift wear points greatly extending safe working life of the halyard. 3. The proper threaded halyard shackles take longer to attach than it takes to tie a bowline. In short, there's no advantage and a lot of downsides, like safety and cost, to going with a shackle.

We've more than 10,000 miles using bowlines, instead of shackles, without a hitch. No conks on the noggin, halyards lasted for the entire cruise, and you can tie them off anywhere.

Don't let the phu-phu people talk you into an expensive, unsafe modification to a safe, efficient arrangement.

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Old 06-06-2007, 12:21   #8
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This IS the correct shackle to use for main halyards...................._/)




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Old 06-06-2007, 16:50   #9
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If you get hold of a Harken catalogue, it will help you out a lot. It has a section on sail loads, with simple formula for calculating loads. Once you calculate the loads, you can then size not only your shackles, but also your rope (halyards and sheets) and your associated blocks and cars, jammers, etc. Remember, the system is only as good as it's weakest link... there is no point in having 90% of your gear correctly spec'ed if 10% of it is under-spec'ed.
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Old 06-06-2007, 18:01   #10
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For what it is worth, breaking strength for standard double braid rope is typically around
3/8" = 3,750 lb
7/16" = 5,500 lb
1/2" = 7,000 lb
9/16" = 10,000 lb

Bear in mind that the load on your main halyard is not just wind load, but should also take into account pre-load from halyard tension generated by halyard winch and cunningham.
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Old 07-06-2007, 09:42   #11
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Many thanks for all the replies
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