I recently read that XM have recalled their Bosun's Chairs Ref 176856 or BC purchased since January 2000. TheMainSail reports: “apparently a chair split while the user was aloft, fortunately with an extra safety line preventing injury.”
On most of the yachts that I have sailed, there's usually some form of bosun's chair tucked away, usually at the bottom of one of the cockpit lockers. I've seen them in all sorts of shapes and sizes, ranging from a short plank of wood and some rope to a purpose-made solid plastic monstrosity that looked like a cross between a child's car seat and an ejector seat from an aircraft!
Frankly, I'd get rid of the lot of them. They're all based on the old-fashioned idea of a plank and some rope that you sit on, and even though you can get ones that look something like a 'chair', I think they're a menace.
Not only do I find them terminally uncomfortable after even the shortest period aloft, with the circulation to my legs and nether regions cut back to starvation diet, but also whilst getting aloft I find it almost impossible to use my legs or feet for anything like the purpose for which they were intended.
A bosun's chair requires a passive occupant - or possibly, a willing victim! You just have to sit there, while the crew do all the work. Try using your legs and feet, and you risk either cutting off the blood supply completely, or slipping out of the contraption altogether. And I dread to think what would happen if I got inverted for some reason. There's nothing much to hold me in!
There is, in my view, a much better alternative to the bosun's chair. It's called a climbing harness. Because it was developed by mountaineers for mountaineers, it's engineered so that you can use both your legs and your upper body. It doesn't cut off the blood flow to the nether parts, and it is, above all else, comfortable to wear and comfortable to sit in.
Mine is a Petzl Calidris. Living in Somerset, I bought it from the local caving supply shop in Wells. It's small, lightweight, comes in its own little bag, and I take it with the rest of my sailing kit wherever I sail. You can get climbing harnesses in most mountaineering shops, and there are plenty available online.
Not only are they comfortable and safe, with a built-in strong point for hoisting and often a second strong point for safety lines, but many of them have built-in hooks or loops for attachments. Ideal if you have to carry tools or other stuff up the mast.
There's no way that you're going to slip out of a climbing harness, even if for some reason you end up inverted. At the same time that I bought my harness, I also bought a couple of lightweight clips, so I can clip on to anything that will give me stability whilst I work aloft. And being able to use my legs and feet as well as my arms means that the crew don't have to do so much work, and I can manoeuvre myself a lot more easily.
Don't forget to use a safety line as well as the hoisting line. Always have two crew members on deck - one to hoist and one to spot, manage the safety line, or to take over if the hoisting crew is incapacitated whilst you're aloft.
And always carry a knife aloft in case one of the halliards gets jammed! I'd much rather be in charge of the cutting process myself. I also take the hand-held VHF with me. Using an inter-ship channel is much neater than shouting, and if for some reason I did get stuck aloft, I have an independent means of calling for assistance.
Having used both, and changed to a climbing harness, I'd never go back to a chair. It's outdated, inflexible, uncomfortable, and just plain awkward to use. I'd much rather trust myself to something developed by mountaineers than to a blue plastic contraption with yellow straps that has little to hold me in.