Rigex Handbook - Lifting Maths

Hi, my name is John Alexander and I work for Rigex, a lifting consultancy company in Aberdeen. I thought you may appreciate the following helpful information on lifting maths.

Click here to download these free pages from our Rigging and Lifting Operations Handbook to help with your lift planning. School, for most of us, was long, long time ago.

Thanks for sharing.

That looks very useful. I have saved it for later use.

Nice. Thank you.

Thank you.

Hi John,
seems to be a bit of an error on page 53

"If the lifting points are all at the same height, uniformly and symmetrically distributed around the CoG then the VRF in each will be identical e.g. in a three point lift each VRF will be one third of the total weight.

If there is no symmetry, they are described as statically indeterminate and should be calculated by structural analysis.
However, in some four point lift configurations if there is symmetry along at least one axis the VRFs can be manually calculated using the following formulae:"

if there are three lifting points the loads on them aren't statically indeterminate, also, it just takes a little bit of slack on your 4 point lift will shift some of the load onto the diagonal pair.