Using a bosun’s chair
Ascending a mast is something most sailors will need to do some day. Often this is a task which is completed rather light-heartedly but the reality is that it’s a high risk operation which – should it go wrong – could result in serious injury, at the worst even a fatality.

Early bosun’s chairs were simply short planks of wood, rigged with rope strops to provide the attachments. They were notoriously easy to fall out of. By contrast, modern chairs like the one above are made of strong synthetic fabric and wrap around the hips of the climber, with straps between the legs and around the waist. The seat itself is usually stiffened for added comfort. Properly adjusted the chair will hold the climber securely in place, allowing him or her to work with both hands without fear of being dislodged. Most chairs come complete with a variety of pockets to carry tools and other necessary objects.

There are also various proprietary devices designed to allow someone to climb a mast unaided but these fall outside the scope of this book. Here we’re assuming at least one other assistant and what can be considered the ‘conventional’ way of getting a crew member aloft.

The climber will be pulled up the mast on a halyard, with possibly another halyard used as a safety backup. For the primary line the main halyard is usually the obvious choice, because:

•    It passes through the masthead which means that security isn’t reliant on the strength of the sheave.
•    It usually leads comfortably to a powerful winch.

Basic points:
The primary line should be tied to the chair’s attachment point with a bowline. Never rely on a shackle or snapshackle – though, if these can be attached as well they will provide additional security.
It’s not essential to rig a back-up line but that much depends on who is hauling you up. I once spent a nervy half hour dangling a couple of metres above the spreaders while the guy winching on deck struggled to untangle a riding turn. Had I used a back-up line I could have transferred my weight to it, thereby making his task easier.

But if you choose to use a back-up it’s better to use its almost invariable snapshackle, since the climber may need to detach and then reattach it in order to negotiate the spreaders.

With this arrangement, you need at least two crew on deck to handle the halyards (plus one more to tail the main halyard if the winch isn’t self-tailing). The bulk of the work lies with the main halyard winchman, with the other taking up the slack and keeping an eye on what’s going on up the mast. Some people like both winchers to share the load, but this can lead to confusion.

•    Note that self-tailers should only be used in self-tailing mode if there are also rope clutches as backups.

Up the stick: the GOLDEN RULES:

Rule 1: While he’s actually winching, the principal winchman should keep his eyes on the winch, not the climber. This will avoid the chance of any riding turns or other foul-ups.

Rule 2: If the halyard winches are on the mast, send the tools up in a bucket once the climber is in place. To have, say, a cordless drill fall from the bosun’s chair onto the wincher standing below could be bad news for everyone concerned – not least for the climber who could follow it to the deck if said wincher became distracted.

Rule 3: Once the halyards are secured, stand clear of the mast while work is in progress.

This method presumes a crew of three but many cruising crews consist of sailing couples, in which circumstances it would be dangerous for a single wincher to be operating two winches. So, an alternative to the backup line is for the climber to use a mountaineering ‘ascender’ (a type of jamming cleat) attached to the chair via a short rope strop and run up a spare halyard which has been set up fairly tight by tensioning it with a winch. Again, the spinnaker halyard is a strong candidate for this role.

... and down again
With gravity now on your side, life becomes less strenuous for winchers, but don’t allow the feeling of relative ease relax your concentration.

Rule 4: Again, as you lower the climber, the wincher’s eyes should be on the drum, not up the mast. Riding turns are more common when easing than when hauling. And ...

Rule 5: The winchers must ease the halyards hand-over-hand, instead of allowing the rope to slip through their fingers. This is in case something sharp – a piece of glass or wire, for instance – may have become caught in the rope, the sudden pain of which might cause a startled wincher to release his or her grip.