It has been a long time since I have been in a physics class.  My question should, I believe, be relatively simple.  We are developing a prototype using a spool, cable, and pulleys to lift a weight.  I would like to know the mechanical advantage presented in the design I am attaching as well as any explanations you might have in how the determination was arrived at.  I am thinking it presents a 6:1 or 7:1 lifting advantage, but I may be way off.  Please feel free to disabuse any assumptions I may have on this.

Doug Rasmussen asked