On Sat, 23 Jan 2010 13:27:44 -0800, Mark Borgerson
wrote:

Way back when, I simply attached a bosun's chair to an external
halyard. By pulling down on the halyard, I went up the
mast. Because pulling down on the halyard reduces the
weight in the chair, you only have to pull with a little over
half your weight.

Ya buttt, it ain't safe, not even half safe.

A better strategy is to use a multi-part tackle with a ratchet block
and cam cleat. With no ratchet block available I'd recommend
something like a 4 part boom vang tackle with a cam cleat.