Originally Posted by JOHN PERRIN
When i had my previous RIB lifted out i but LARGE FENDERS (sausage type) between the sling and the hull this stopped the slings collapsing the tubes,
Not to beat a dead horse but using this method would amplify the pinch force on the hull in an area that the hull is not designed to be pinched, even as you "protect" the tubes from compression. Spread the lift point of the slings outboard of the tubes and viola...problem solved. I would think that most conventional rigid hull pleasure craft have a beam equal to or greater than most ribs so therefore a properly equipped boatyard should have the equipment to sling without compressing the gunnels, tube or no tube.
The further complication with a proper spreader is to be able to position the fore and aft sling in the correct location to balance the lift. A non-adjustable spreader for lifting a 18 meter vessel will not be correct for a 4 meter vessel in terms of fore/aft placement.
It comes down to competency of the boatyard and most who are actively handling a large assortment of lifts probably have the awareness and equipment to avoid problems. There are however some pinchmeisters out there, I'm quite sure.
Any hull builders out there who care to comment? I'd be interested as to how much or little the shell of a hull is affected by compression or what design thought goes into the eventuality that these hulls will be slung. I don't think there's any argument that severely compressing tubes is not a good idea at all what with their mechanical joining to the hull. It ain't natural which brings to mind Mr. Natural who says, "Get the Right Tool For the Job"