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Old 23-11-2015, 13:32   #31
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Re: Jacklines - how to?

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Originally Posted by gulfcoastsailor View Post
May I suggest that 99% of any pleasure sailboats connection points are not strong enough to safely secure a jackline. Start from scratch no matter what your plan.
??? Though I have heard of harness failures, I an not aware of a single deck cleat failing from jackline loads. Documentation? This is a very common practice, so it should have happened by now, particularly if 99% are too weak. I think they are OK.

A single 5/16" bolt will generally hold about 5000 pounds in shear, and most bow cleats are 2x3/8". Climbing bolt hangers are rated at 5000 pounds on a single bolt.

Small boats (<30 feet may have smaller cleats, but the impact force and actual required strength is much less for them.

I agree that dedicated anchor points are good for a number of reasons. My favorite reason is so that they are run correctly every time (not over the wrong control line). Of course, they must be well engineered and backed.

There is an article on this in Nov Practical Sailor.
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Old 12-07-2016, 05:52   #32
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Re: Jacklines - how to?

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Originally Posted by Glenn.Brooks View Post
Something else to consider - the singlehanded Transpac and I believe other offshore Pacific races require jack lines and fittings be 5000 # breaking strength. This requires truly massive deck hardware connections and webbing. I doubt if 1" webbing would meet the requirement, probably requires more like 1/4" x3" webbing. In any event, most hardware will,have a breaking strength stamped into the fitting, so usually is easy to vet, to determine which ones are strong enough.

I have no idea why the requirement is to stringent- someone said that 5000# is a minimum OSHA requirement for safety lines.
The requirement comes from the shock a person (250lbs) generates after falling a specific distance (6feet iirc). There is 1 inch webbing rated at 6,000 lbs sold this west marine and Wichard. LRSE custom makes 9,000 lb jack lines using webbing.
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Old 13-07-2016, 01:19   #33
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Re: Jacklines - how to?

Quote:
Originally Posted by thinwater View Post
??? Though I have heard of harness failures, I an not aware of a single deck cleat failing from jackline loads. Documentation? This is a very common practice, so it should have happened by now, particularly if 99% are too weak. I think they are OK.

A single 5/16" bolt will generally hold about 5000 pounds in shear, and most bow cleats are 2x3/8". Climbing bolt hangers are rated at 5000 pounds on a single bolt.

Small boats (<30 feet may have smaller cleats, but the impact force and actual required strength is much less for them.

I agree that dedicated anchor points are good for a number of reasons. My favorite reason is so that they are run correctly every time (not over the wrong control line). Of course, they must be well engineered and backed.

There is an article on this in Nov Practical Sailor.
It ain't likely to be the gonna be the bolts that fail, nor the cleats: If anything is it likely that the cleat and bolts are gonna pull clean out of the deck, especially if appopriate backing plates are not used. The problem is that the line of load application is generally at 90 degrees to the line of the jackstay which "multiplies" the load seen at the cleat quite significantly.

FWIW, we have used the Wichard webbing jackstays - these are excellent
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Old 13-07-2016, 01:26   #34
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Re: Jacklines - how to?

On the subject of jackstays:
Aside from the standard jackstays that run the full length of the boat along the side decks, it is a good idea to fit hard points for an additional jackstay that runs from the companion way along the centreline of the cockpit sole. The jackstay should be accessible from inside the boat (i.e. you should be able to clip on before coming on deck, and should allow you to access all cockpit winches, lines, wheel or tiller, port and starboard, while clipped on. It is a really good way to stay safe. We use this all the time if out of sheltered waters and / or sailing in adverse conditions or at night. In fact we used excess webbing left over from the purchase of our Wichard jackstays for the side decks to make this "cockpit" jackstay.
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Old 13-07-2016, 14:03   #35
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Re: Jacklines - how to?

How do you guys tension your jack lines. Mine almost run the full length of our 40' cat and feel a like there is a little too much stretch in the middle.
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Old 13-07-2016, 15:01   #36
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Re: Jacklines - how to?

^^ as I said in other thread - 'snug' is just fine.

But are you using nylon webbing? It will stretch quite a bit. Polyester webbing is better (and more uv resistant).
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