Another way of doing it:
Mast Raising From The Bridge? | TownDock.net, Oriental NC
Not that I would recommend it! Oh and you want to say un-stepping the mast, as de-masting is normally a phrase reserved for an unintentional incident! If you are having the yard do it it should not be a big deal as they have likely done it a few times. I like to supervise any work as they seem to take more care when they know you are around, but I don't interfere with there work. If you are at a yacht club and using there equipment, you might want to make sure you round up a few experienced folks to help. With the latter situation having some cold beer as post celebration is often a good way to make sure someone is around next time!