Tried yesterday to lift my 6.5m Humber with its dead Honda 130hp out of the water to start work on it. I tried to use a hiab with straps, however the straps were just digging into the tubes. So we abandonned it.
Not before using two long planks of wood between the straps to stop them closing in on the rib. But that failed too.
Can ribs only be taken out with a negative lift forktruck or on a slipway?
Tried yesterday to lift my 6.5m Humber with its dead Honda 130hp out of the water to start work on it. I tried to use a hiab with straps, however the straps were just digging into the tubes. So we abandonned it.
Not before using two long planks of wood between the straps to stop them closing in on the rib. But that failed too.
Can ribs only be taken out with a negative lift forktruck or on a slipway?
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.
You really do need a spreader bar. Have a look here: www.dryberthing.com and see how the professionals do it. When you use a spreader bar, make sure your tubes are inflated hard, and although they will deform, they won't get pinched between the attachment flange and the lifting strop. They will also keep the load off the atachment flange which isn't designed to suppiort the weight of the RIB over four six-inch sections. Three point lifting kit like Nauti Buoy describes is ideal, but if you ain't got it, then you ain't got it.
All good ideas but just remember all lifting equipment is subject to the Lifting Operations and Lifting Equipment Regulations that stipulate regular checks and inspections that must be certificated by an approved body.
This isn't just strops, but also chains and links.
Tried yesterday to lift my 6.5m Humber with its dead Honda 130hp out of the water to start work on it. I tried to use a hiab with straps, however the straps were just digging into the tubes. So we abandonned it.
Not before using two long planks of wood between the straps to stop them closing in on the rib. But that failed too.
Can ribs only be taken out with a negative lift forktruck or on a slipway?
Its not a good idea to lift a Humber just with straps unsuported like that due to their design. Its possible with some RIBS but the way the hull meets the tubes on a Humber doesn't do the hull a lot of good due to the squeezing you'll get - tube inflated or deflated.
Humber sometimes do fit the lifting eyes like Richard mentioned. Its the best way..... though the spreader bar might be OK if you feel lucky!
You could always give Humber a ring and get some advice from them. If you have the boats serial number they may even know if lifting eyes can be added easily ... or are there now!
All good ideas but just remember all lifting equipment is subject to the Lifting Operations and Lifting Equipment Regulations that stipulate regular checks and inspections that must be certificated by an approved body.
This isn't just strops, but also chains and links.
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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A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...
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.
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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A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...
I realised after I replied that you are in the Falklands sorry.
Quote:
Originally Posted by BogMonster
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.
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!
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.
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.
sorry.
