[UK-CONTEST] Gin Pole Pulley system

[Dave Lawley]

Have to say the last of Stewart's pictures gives me the horrors! No 
useful purpose is served by a person being at the base of the mast, but 
if anything breaks then he stands a good chance of being killed or 
seriously injured.

The great thing about the gin pole / block & tackle system is that one 
person can put up a 70ft mast single handedly, and keep well out of the 
danger area.

How you rig the block & tackle depends on how many sheaves there are on 
each block, but with two double blocks you need the rope tied to the 
upper block, i.e. the one attached to the top of the gin. It's important 
to use the correct diameter rope for the sheaves you are using, to 
minimise friction. You need as much of your effort as possible to go 
into raising (or lowering) the mast. Braided rope is better than laid, 
if you do use laid rope make sure you don't end up with the two blocks 
twisting relative to one another, which will give you a big friction 
problem.

When doing it single handedly it's rather important to have the back 
guys tied off! If you're on flat level ground and can arrange the side 
and back stakes to be on the same radius then you can measure the back 
guys against the side ones and tie off at approximately the right 
length. While on the subject, even on level ground the side guys on the 
gin can sometimes get very tight so it's as well to start off with them 
on the slack side.

When the mast is nearly vertical, you'll probably be a long way out, 
having pulled on four times the length of rope compared with the 
starting distance between the blocks, so you then need to walk forward 
to the gin pole (the end would typically be a few feet above ground) and 
then pull in the last few feet of rope and tie off.

Easier to do than explain!

Dave G4BUO