I used pulleys and block and tackles when I was building microwave towers in the army, but never gave it much thought as to how they worked.
What I knew was it normally took 8 guys to hoist my tower sections or antenna mounts up to me using a single pulley system, but if we were shorthanded, I could add a block and tackle and reduce that to 4 or even 2 men.
When the ground crew was clowning, all 8 guys would grab their end of the rope and take off running when they got my signal, and with a block and tackle setup, that tower section would go up so fast it looked like it was falling up.
