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Old 06 February 2007, 10:52   #11
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two cranes for sale a 35ton all terrain and a 10 ton must have been doing it wrong all this time .

let the tubes down long strops its easy and the correct way when lifting points are not fitted .

and we do a rather lot of lifting over 300 boats in at the moment

we lift every rib this way on land and as long as the banksman knows his stuff its fine

althouh we have 12 ton a sub lift for when its in the water just makes life easy.

but ive yet to see a spanish yard or french yard not do it this way with a crane
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Old 06 February 2007, 10:56   #12
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Some ribs have fitted a 3 point lifting kit. I specified one on mine when I had it built and basically it is 2 eyes on the transom and one inside the tubes at the bow, fixed through the deck. Then I had a lifting harness made up which cost 125 with Certificate for Lifting Rating (Most Marina's ensure you have this if you want them to use your rig) Have used this twice now and it is superb.

regards

Richard
That's an interesting idea...

I have an eye on the inside of the hull up in the bow, next to the external eye but just bolted through the other way round (used for tying the anchor to, apart from anything else). While there weren't any eyes on the inside of the transom on mine when I got it, I replaced the ski hooks with M12 eyebolts which have "eye-nuts" on the inside so I could actually rig up something like you have... hadn't thought of using 3 point lifting!

Apart from trial and error I wonder how you work out the C of G of the boat/engine combination?
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Old 06 February 2007, 11:03   #13
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Apart from trial and error I wonder how you work out the C of G of the boat/engine combination?
Not sure, I was lucky enough that someone else had already purchased a similar set up to my rib and had done the donkey work, ie strap lengths etc and given them to Parker Ribs, who inturn gave me the length measurements so I could get my straps made up and the are spot on.

The company I used to make up the straps for me can also make them up if you call them first and take your rib over to them in Cowes they have a set that they use that are adjustable so they can work out the length required to equally lift the boat. Also the front strap is heavier grade than the 2 rear ones. From memory the 2 rear straps are 3.5 tonne each capacity and the front 4 tonne. Over the top I know but better safe than sorry.
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Old 06 February 2007, 11:09   #14
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take your rib over to them in Cowes
could be somewhat problematic

Lifting safety factors are usually somewhere between 5:1 - 7:1 I think so using 4 tonne straps is probably about right for yours if the boat weighs a couple of tonnes all in.

I'd probably never need to use it, just an idea to have at the back of my mind "just in case"

The only concern I would have is the strength of the hull around the bow eye, no way the others will pull out or break but I think the one on the sharp end is only about an M8 U-bolt and I wonder how thick/strong the hull is around that area.
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Old 06 February 2007, 11:22   #15
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could be somewhat problematic
I realised after I replied that you are in the Falklands sorry.

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The only concern I would have is the strength of the hull around the bow eye, no way the others will pull out or break but I think the one on the sharp end is only about an M8 U-bolt and I wonder how thick/strong the hull is around that area.
Some could be a problem, on my I have the front Samson post with the lifting eye incorporated into it. The Samson Post passes through the deck where it is bolted to the deck, plus it is also fixed to the hull as well, so well and truly not going anywhere......... I hope.
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Old 06 February 2007, 12:32   #16
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I asked the same question with a post called "Lifting a Rib" which I posted on 14 August 2003.

Lots of interesting responses and photos.

I don't know how to post a link to that thread but you could do a search.
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Old 06 February 2007, 12:37   #17
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Found it

http://rib.net/forum/showthread.php?t=2554
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Old 06 February 2007, 15:49   #18
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The only concern I would have is the strength of the hull around the bow eye, no way the others will pull out or break but I think the one on the sharp end is only about an M8 U-bolt and I wonder how thick/strong the hull is around that area.
Strongest part of the hull, usually. Think about the construction, there's loads of glass in there.

Also, I've seen enough sailboat collisions to know that the bow usually comes trough relatively unscathed!
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Old 06 February 2007, 16:33   #19
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The bow will probably be the thickest part of the hull as you have the overlaps from either side of the hull and then where the floor is glassed to the hull, and if it has a plywood block where the ubolt is through bolted will be glassed into place aswell.

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Old 06 February 2007, 16:57   #20
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Lifting safety factors are usually somewhere between 5:1 - 7:1 I think so using 4 tonne straps is probably about right for yours if the boat weighs a couple of tonnes all in.
On my IRATA Rope Access Technicians course we were told to work on a safety factor of 10:1 for anything fabric, and 3:1 for anything metal.

Although those numbers are probably based on shock-loading in case of a fall.

Familiarise yourself with LOLER before doing anything.

Cheers, WMM
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