VO5
New member
A week to be exact.
Is it possible to lift a boat up by her chainplates ?
- Thread starter Boo2
- Start date
Channel Ribs
New member
So in summary...
The chainplates are likely to be strong enough, but the work involved in ensuring the load is delivered cleanly and when balanced with the potential for catastrophic damage all suggest that most of the traditional options are far and away preferable.
The chainplates are likely to be strong enough, but the work involved in ensuring the load is delivered cleanly and when balanced with the potential for catastrophic damage all suggest that most of the traditional options are far and away preferable.
davidej
Well-known member
I expect you will think that (just like Gordon Brown )I am defending the indefensble, and I should know better than answering posts from Boo .... BUT
I totally take the point about wave action be an importantp art of 360 degrees rolls .However on a simple wind powered lay down, to a very rough degree of accuracy the righting lever of the keel will not be very different to the capsizing lever on the shroud. I know a proper analysis required metacentric heights, c of g etc but a shroud ( and I assume its chainplate) it stressed to something like 5x the static load- I am sure my analysis is within that sort of factor.Thus since the keel is 50% of total weight, I think it is a fair assumotion the one plate wouds easily carry 50% of the weight.
If someone is prepared to volunteer their boat, I will bet £100 that you could lift if suspended from the mast-top.
mollyoxford
New member
seen a scheme for attaching legs that uses the chainplates. Think it was on Atom's Voyages website? http://www.atomvoyages.com/
bbg
Active member
Completely irresponsible. Can't imagine anyone ever doing it, with any boat.
Edit - OK, I've been a bit cheeky posting that. My boat is designed not to be lifted with straps under the hull (the yard positively says DON'T lift that way), but with strops fitted to padeyes at the gunwhale. This photo shows the forward load distributed between the lifting padeye and the chainplates. But it would not have surprised or bothered me if the entire load had been taken by the chainplates. On this boat.
Further edit - the loads on the forestay and backstay can be enormous. I recall reading that the mast compression loads and stay loads on an America's Cup (5th generation) boat were such that you could lift the boat by the forestay and backstay fittings. Then put the weight of a fully loaded 747 on the keel step, and the boat would deflect by about 25 mm in the middle.
I suspect that most boats could be lifted pretty easily by their chainplates without risk. But I wouldn't want to have to explain it to my insurer if mine was one of the unfortunate few that couldn't.
Edit - OK, I've been a bit cheeky posting that. My boat is designed not to be lifted with straps under the hull (the yard positively says DON'T lift that way), but with strops fitted to padeyes at the gunwhale. This photo shows the forward load distributed between the lifting padeye and the chainplates. But it would not have surprised or bothered me if the entire load had been taken by the chainplates. On this boat.
Further edit - the loads on the forestay and backstay can be enormous. I recall reading that the mast compression loads and stay loads on an America's Cup (5th generation) boat were such that you could lift the boat by the forestay and backstay fittings. Then put the weight of a fully loaded 747 on the keel step, and the boat would deflect by about 25 mm in the middle.
I suspect that most boats could be lifted pretty easily by their chainplates without risk. But I wouldn't want to have to explain it to my insurer if mine was one of the unfortunate few that couldn't.
Last edited:
Bilgediver
Well-known member
And stand by with a few hundered wee nuts and bolts and Sikaflex in case the deck jount fails if the chain plates are secured only to deck with penny washers as on several elderly popular designs
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