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Working aloft with a bosun's chair and safety line

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What is the issue?
It is only a matter of time before a sailor has to go aloft to inspect the rig or attend to some repairs.

Why address this?
This task can be nerve-wracking for some, or at the very least physically demanding and uncomfortable, but in all cases dangerous. Anything that reduces any of these issues is welcome.

How to address this?
Bosun's chair and safety line
Drawing: Tony Gibson
Include a Bosun's Chair, or boatswain's chair, in the boat's toolkit. A bosun's chair is a seat used to suspend a person whilst going aloft to perform rigging work.

Originally just a short plank or swath of heavy canvas, many modern bosun's chairs incorporate safety devices similar to those found in rock climbing harnesses. The best chairs are the deep-sided canvas type with lots of pockets all the way around that have covers or velcro to close them off.

If you have not bought a specially designed bosun's chair already it is worthwhile making one up, as illustrated, to alleviate some of the danger and discomfort of any work that has to be attended to on the mast. All that is required is a piece of hardwood wide enough to sit on drilled through four times plus the lines and splices.


The primary consideration when going aloft is to ensure that everything is done for safety and comfort so that the task is carried out as efficiently as possible. This starts before the chair is even approached, by selecting protective clothing. Long sleeves and trousers are essential to prevent flesh being chafed or nipped between halyards and the mast which can be very painful.

Safety and comfort should be the primary considerations when going aloft
Image: Ian D. Keating via CC BY 2.0

When first getting set up in the bosun's chair it is important to be secured in such a fashion that it is impossible to fall out, even if consciousness is lost. The safety line arrangement as illustrated, which is passed around both the chair and the back of the person seated in the chair, should be used. Should the hoisting line fail or come loose, the safety line will be a lifeline. A further measure of security can be added by using a Tarbuck knotExperience as a secondary safety measure whilst ascending.

When it comes to going aloft, try to select a halyard whose block is closest-above the working point to reduce the chair's free-swinging scope should it become detached from the mast. Use a screw shackle or a bowline for attachment to the chair and avoid using any existing snap-shackles that happen to be on the halyard. When at the work point secure a line around the mast so as to be held firmly in position. This will free up both hands for the task and minimize the risk of personal injury from being slammed against the mast if the vessel should roll.

The person in the chair should keep all tools in a separate canvas bag attached to the bosuns' chair as this is less likely to catch and tip. Each one of the tools should be on a safety line in case they are dropped, which could cause damage the deck or more likely be lost overboard. Likewise, keep the area beneath the mast clear in the event that something does drop.

This is particularly the case with the winch operator who, if struck and injured by any dropped tool, will then compound the issue by letting go of the rope tail. If the halyard winch is set up at the base of the mast, rig a block and take the line to a cockpit winch to get clear of the dangerous position. Tie off securely when aloft and have the winch operator belay the line on a cleat even if it is already in a cam or on a self-tailing winch.

With thanks to:
Michael Harpur, Yacht Obsession. Header image with thanks to Twinrudders.

Harken Bosun's Chair

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