He talked physically modifying the hook and tackle block (wheel above the hook). Cranes are very specifically engineered to be used as designed. Modifying them without an understanding of what you are doing and getting it signed off by an Professional Engineer is a big nono and will get your insurance yanked VERY quickly if you’re lucky. The unlucky result is a failure of the crane resulting in someone’s death. That would cause him to be liable in a civil suit and possibly even criminally negligent.
Side note: This is why engineers, Especially ones with Professional Engineer (PE) licenses are paid so much. We are required (in the US) to graduate with a 4 year degree in engineering from an accredited school, pass an exam, work for 4 years in an engineering field under a PE, pass another exam, and then pass a character and fitness (background check). Only after this is done can we stamp (certify) plans. Our license is used to show we know what we are talking about and therefore assume the liability that the crane (or any other object) function correctly when used according within manufacturers specifications. If you want a good look at what happens when engineers screw up look at the Hyatt regency disaster
Here.
As for what he specifically wanted to do, currently the end of crane cable is attached to the top of the crane. From there it comes down, loops through the tackle block (wheel with the hook) goes back up to the sheave (wheel at the top of the crane) and down the the winding drum (drum the cable winds on). By having the cable double back on itself using the tackle block it doubles the lifting capacity of the rope in exchange for halving the speed. Since the crane was designed like this, the simple act of removing the cable end from the top of the crane and just attaching the hook to it will immediately halve the weight capacity of the crane. All so he can lift stuff faster.
Video about pulleys and block and tackle
By modifying the crane it is no longer being covered by the original specs and he will be held liable.
Hadn’t looked at the spec sheet on it. Didn’t realize it drew so little. I’m used to heavy 3ph stuff. That being said I’d like to see more about his power set up. I don’t know much about electrical but I do know that stuff like that can be picky about how consistent the power supplied is. I’ve seen flaky power from a brownout fry the controllers in CNC machines.
