how to flip over boat for bottom work

I know some have done this before but can't find a post. My friend is going to re-gelcoat his entire 74 South wind 20. One of the previous owners thought it would be a good idea to paint the entire bottom of the boat!

So. I work for a sign company and we were thinking we could pull the engine with the crane truck and then lift the boat with straps fore and aft, and gently roll the boat over in the straps and lay it back down on some wood runners across the trailer. At least my crane operator thinks he can.

Does anybody have a better or easier way to rotate the boat like a rotisserie? And I am assuming leaving the engine in would be catastrophic.

Thanks - kirk

That looks like what we would be doing with the crane. A spreader bar at the top with two straps. My crane operator says he has rolled heavy signs before...

What about the engine removal. That must come out first, right?

You can use a fork truck with a spreader bar its not the best way and you need to be real careful have some old tyres on the floor under it too, be safe
   

I would also hook a chain fall on it to control the rotation better

Hook the fall above the pick point
Then hook the chain to a choker that's choked around the boat..
I would only attempt this if you have heavy rigging exerance!
Things could go really bad quick