Re: Going up the mast
I second the ideas of. . .
--an extra line to send up forgotten stuff
--rigging tape (you'll always find a little bit coming off somewhere)
--camera (for the fun photos but ALSO to document stuff for the skipper). I go aloft annually for the guy I crew for. I went aloft just a week ago to replace the burned out anchor light.
Harness comment: Do make sure that it stills allow circulation in your legs.
On two halyards: DO IT! Do you want to trust your life to ONE line? No.
Some folks commented to use two halyards attached to your bosun's chair. I do not like this--what happens if you fall out of the chair? Two halyards don't matter then. On the chair that I use, it's conceivable (although not likely) to fall out on the way up or down if I perhaps catch a foot on a spreader or something.
Instead, here is the solution that we use:
I wear a safety harness. To the harness, I attach the spare halyard with a bowline. For good measure, I then clip the shackle end to the harness as well.
Then, I sit in the bosun's chair. To the chair, we attach the primary halyard with a bowline.
I've weighed as much as 180+ over the years and this has worked--the boat is a 37' Hunter.
The strong person grinds with the primary attached to the chair. The goal for the second person is to keep just a touch of slack in the halyard attached to the harness. Being just a regular safety harness, it is NOT comfortable to have one's weight fully supported by the harness. But, if the primary and chair somehow failed, the harness would prevent serious injury.
It's fun to go aloft, just be careful.