Haul out harness specs

[EarthBM]

Does anyone know the lengths of the harness straps to be used for haul out via the lifting eyes?

[Double Horizon]

I use 20-foot load-rated polyester lifting straps for the 1200. This works better than the 18-20 foot factory-supplied steel lifting harness, which had uneven lengths (front/back). I doubt the length is critical, but it must be long enough to clear the lazy-jacks and avoid excessive side-loads on the lifting eyes.

Edit: I feel much more confident in the polyester load-rated straps than the made-up stainless rigging supplied by Quorning. The Wichard quicklinks supplied by Quorning have deformed, and my boatyard said that they didn't want me to keep using them. The steel wire was only 8mm, which is rated 5040KG breaking strength or 1680KG SWL if you use a minimal 3:1 factor. I am now using US-made 5/8" Crosby shackles that are each rated 3.5T SWL (with a 4:1 safety margin) along with the much stronger webbing that is rated for overhead lifting and has safe load indicators built into the stitching.

[EarthBM]

I want to construct my own harness from .5" Dyneema (15.4 ton ISO strength). Splice the ends that go through the eye bolts, and splice+shackles on the other end.

I recall that the factory harness had a strap rectangle that united all four lifting roped in the middle. What's its purpose? I cant find the picture of the factory harness -- does anyone have it?

[EarthBM]

Found the picture.
Please click on the photo to see it enlarged!

It's not a rectangle - just a fore and aft straps to align the rope with the eyebolts...

Even if the four ropes going from the eyebolts to the crane hook are long enough to clear the lazy jacks, how do you prevent the mast from hitting the crane?

[Double Horizon]

snip

Even if the four ropes going from the eyebolts to the crane hook are long enough to clear the lazy jacks, how do you prevent the mast from hitting the crane?

When using a crane, people on the ground need to use dock lines (attached to deck cleats) to keep the boat from spinning or turning the wrong way.

[EarthBM]

Thanks Larry, this should work if not too windy.

Have you ever tried using the "platform lift" (you sail over the platform, then blocks are placed under the bottom and drom the sides, then the platform lifts)?

Kind of like this:
http://tiptopwebsite.com/photos4/6400marina/26.jpg

[Double Horizon]

Never a platform lift; but I used to launch and haul out my DF920 and DF1000 using a rail car with my cradle tied to it. The rail car was attached to a cable that was hauled up by a winch on land. The tracks sloped into the water and could only be used for launching at mid-tide or higher. For haul out there were vertical corner posts on the rail car we tied onto while the boat was still floating, but it was risky if the boat was positioned wrong on the cradle as it came out. I would not recommend this method.

Launch was very dramatic though -- we'd remove the vertical posts and cable, and push the car until it picked up its own speed. The boat would accelerate down the track and enter the water with a splash, with me aboard.

[Bo Wetzel]

Hier is a picture showing a 920 on a crane hook with a set of original lifting cables:
Please click on the photo to see it enlarged!

[EarthBM]

Thanks Bo! Looks like sideways loads on the eyebolts are ok for 920's weight, based on the angles in the picture.

Larry,
I don't have the cradle anymore. Think the link I posed in the previous post is the rail car you just described. I tried lifting with the platform and abandoned it in the process, just didn't feel right. The railcar looks even more hairy.

Think I'll get 2x50' of 1/2" Amsteel blue, use overhand loops in the middle for the crane hook, splices or overhand loops + shackles at the eyebolts.

[Double Horizon]

The eyebolts should not have sideways loads. If the crane lifting bridle is used, with a crane -- the eyebolts should be rotated so that they are inline with the pull angle (the angle of pull should be inline with the metal loop that forms the eye of the bolt) so the eye isn't pulled off to one side and bent.

If making lifting slings from Dyneema I would caution that it is slippery and knots don't hold well -- and can weaken the fiber. I'd recommend you make up 4 pieces with end splices around thimbles, with a minimum splice bury of 72x the diameter of the line (36" for 1/2" line). The buried tail should be tapered.

I have some 7/16" Amsteel I'd consider selling. Richard S has my contact info if you're interested, or you can find me in the Dragonfly owner's list. However, I'd advise you to get 20-foot pre-made polyester lifting straps that are load-rated for overhead lifting. Mistakes can be costly (or fatal) when lifting your boat with a crane.

[EarthBM]

I hear you on aligning the eyebolts!

Also on splicing... The problem is that I haven't done it, and this is probably not the best first application... Will find a rigging shop I guess.

The excellent http://www.bethandevans.com/load.htm resource basically shows splices in the 95% area of breaking load, while the best knots (fig 8 loop, palomar, alpine butterfly) slipped at 40-50%. That was for 1/8" Amsteel. Breaking strength goes up as square of diameter, while slippage resistance increases linearly*. So for 1/2" Amsteel the knots will slip at 10-12% of breaking strength, or at 1.5 ton. So this leaves me at just 150% safety factor (4x1.5 ton = 6 ton vs 4ton boat weight).

* I suspect the same math applies to splices, but I don't know enough about them. I guess this is where you x72 number comes from.

My email is my forum name at gmail, can you send me the details of the 7/16" Amsteel you have?

[Double Horizon]

I've done a lot of Amsteel splicing, and it's not difficult.

These are the instructions I use http://www.colligomarine.com/docs/misc/ ... ev_1_2.pdf

Will email you.