Oops! Found out I posted these pix last year... but I'll leave them up.
I was doing enuff engine replacements and rebuilds that I needed something to get the engine's in and out without having to line up a fork lift or loader and get it to the boat.
This was my solution.
Disassemble a couple old boat trailers for the parts and start assembling. Then figuring out the best way to get 10' of height from the crane and still be 'portable'...