ghostlymoron
Well-Known Member
A 25T crane will lift 25T at 1m radius but only 1T at 25m radius.
If you dont have a spreader there is a crushing force. Use long chains and this is reduced, but there is still a crushing force.
So use spreaders.
Depends on the boat. Our previous one was built like a brick outhouse and quite happy being lifted by a HIAB with no spreaders. A bad hull shape for strops slipping off the ends, though, so they were firmly secured to the winches and the mast tabernacle.
The new boat is more lightly built, and I'd want spreaders used there.
Pete
…….. lifted the rowing boats with very long slings but no sopreaders, and the crushing load still broke the first boat.….. You can get away without spreaders, but only because the boat might be strong enough.
On quest tv a while back there was a feature about a heavy craning specialist that took all the deck gear off HMS victory while restoring her. On camera they lifted the rowing boats with very long slings but no spreaders, and the crushing load still broke the first boat.