There is also a device called a "Gin Pole" that can work well. It is used for raising the ridge beam on barns (ever wonder how they did that "back in the day").
Here is a link to one used for sailboats, pretty neat.
One word of caution, if you don''t watch what you are doing, all heck will break lose.
My marina had used a Gin Pole at the pit for masts, until some folks though it looked so easy that they tried to do it by themselves one Sunday. Result? Broken mast, Gin Pole, and about $30,000 damage to the boat near the pit that they dropped the whole rig on!