How to Climb the Mast – Safely!

by Frank Lanier
Southern Boating (2007)


I’ve watched plenty of sailors go aloft over the years and while most manage to accomplish it in a relatively safe manner, just as many approach the whole evolution with a decidedly cavalier attitude, one seemingly bordering on a death wish at times. A ratty, seldom used bosun’s chair excavated from the bowels of cockpit locker, a worn halyard and a passerby (or wino from a nearby gutter) to crank them up the mast and away they go with nary a though to safety procedures, gear inspections, or any sort of preparation for the job at hand.

All sailors eventually find themselves facing a climb up the mast and while proper planning can make it a safe, even enjoyable experience, it’s still likely the most dangerous evolution aboard, one that can easily result in serious injury or death. Let’s take a look at some basic precautions geared to make any climb up the mast a safe, productive experience.

Getting there is half the fun

There are a number of options available for going aloft, from mast steps (both fixed and removable) to a wide assortment of harnesses and self-climbing arrangements designed for or adapted to climb the mast. The most common method (and focus of this article) however, remains use of a bosun’s chair, preferably in conjunction with some form of safety harness. Much of the preparation and safety information discussed below can be applied to any mast climbing situation, however be sure to follow specific instructions provided for your particular mast climbing set-up.

Pre-ascent planning

  1. Plan out the work you need to accomplish aloft and discuss it with your crew/helpers before any feet leave the deck. Ensure everyone knows their role and that “the plan” address any special circumstances to the extent possible (fouled halyards, the need for additional tools, who to call if you get stuck up there, etc).
  2. As you (or whoever the climber is) will be totally dependant on the ability and attentiveness of your deck crew, do yourself a favor and get someone who has a least some experience, even if it means scheduling your climb around such a person’s availability.
  3. Establish or review existing communications to be used between the deck crew and climber while aloft. Short or one-word commands often work better than full sentences, which can be carried away by wind or garbled due to noise or height above deck. Make sure commands are agreed upon and that everyone understands their meaning – it’s also a good idea to get in the habit of repeating a command once heard, both to verify it was heard and to assure whoever issued it (be it climber or deck help) that it was heard correctly.
  4. Unless it’s some sort of emergency, schedule your climb with the vessel in calm waters, preferably during a time of day when there is little or no boat traffic to reduce boat movement. Along those lines avoid climbing in rough or windy conditions if possible.

Gear and rigging

  1. Conduct a full inspection of all gear each time prior to going aloft, including the condition of halyards, wire-to-rope splices, etc.
  2. Always use a full climber’s harness in addition to a bosun’s chair (a full harness being one that covers and provides support to both chest and lower torso/below the waist areas). Fabric bosun chairs with waist belts, crotch straps, and back support provide a greater sense of security than the traditional plank used to go aloft, but if you lean over too far (such as when inspecting a spreader tip) you could still fall out. Full harnesses (such as those used for rock climbing) work great, are fairly inexpensive, and when properly fitted will hold you securely in place at all angles, even upside down. In fact, if the climbing harness is comfortable enough you may be able to omit use of the bosun’s chair altogether, although you’ll still want to use two halyards for additional safety.
    Marine safety harness should not be used however – they’re designed to keep you from falling overboard (not to catch or support a body falling from a vertical distance) and could even cause additional injury.
  3. As mentioned above, always use two halyards (preferably with internal masthead sheaves) – one for the chair and one for the safety harness. Your deck assistant(s) will need to tend both of these lines as you ascend, keeping them tensioned with a couple of turns around a winch (to catch you if something gives) and cleating them off once you are in position. You don’t want them to lift you by the harness, however you also don’t want any unnecessary slack, which equates to less of a drop should the chair or its halyard fail. Halyards are static lines, meaning they have little or no stretch to absorb the shock-load of a falling body and could snap if so exposed.
  4. Some sailors advocate the use of locking carabiners or screw pin shackles to attach halyards to your chair or harness, which allows you to attach or unattach and untangle yourself should the halyards become fouled. As a matter of personal choice I prefer to attach lines directly to the chair and harness with a bowline or other suitable knot, however if you choose to use carabiners or other such attaching hardware make sure they are of the locking type – non-locking units can open accidentally if bumped or snagged.
  5. Gather all the tools you’ll need to complete the work aloft and ensure each are secured via lanyards to either the bosun’s chair, climbing harness loops, or tool bucket. The reason for this is twofold – it keeps you from losing tools overboard or (worse yet) dropping them on your assistant’s head. My personal preference for transporting tools is a large, canvas bucket with a reinforced mouth, one with a lanyard long enough to reach the deck or attached to a separate halyard if one is available. It’s easer to reach the tools (as opposed to digging for them in a bosun’s chair pocket), you have a ready receptacle to put stuff in as needed, and you can easily lower the bucket to bring up heavier tools (so you don’t have to climb with them) or retrieve additional tools or parts if needed.

           Basic tools and stuff I generally carry aloft regardless the job at hand includes a good sharp folding knife (preferably with a serrated blade and marlinspike), medium sized flat and Philips screwdrivers, 8” crescent wrench, a small length of stainless steel mousing wire, rigging tape, and a few pieces of small stuff line. I like to combine any trip aloft with a general rigging inspection where possible and try to be ready to address the more common problems I typically find. I also normally bring up one of the various multi-tools I have onboard (Gerber®, Leatherman®, etc) although in my opinion they typically just keep you from getting the proper tool needed for the job.

Hints for heading up the stick

  1. Take your time – regardless the method you use to climb the mast, go slow, be patient, and be safe.
  2. If possible have at lest two helpers on deck, one to man the winch and one to tail the main halyard and harness safety line. If a third is available, let them mind the safety line, which allows the number two helper to concentrate fully on tailing the main halyard. Keep both halyards tensioned at all times during the evolution to prevent a fall.
  3. The person being hoisted aloft should attempt to climb the mast as much as possible, both to reduce the amount of jerking on the halyards and to give the poor deck ape manning the winch as much help as possible. Also, during ascent only the climber should give orders regarding raising or lowering the halyards.
  4. Once the climber is in position, tie off both halyards securely. Never rely on self-tailing winches in leu of cleats and use separate cleats for each line. For added security the climber can also carry a short “working line” that can be attached between the chair support rings and some point on the mast (one that doesn’t allow the line to simply slide down the mast in the event of a fall).
  5. Once secured in place, the safety observer should clear the deck area of crew immediately below the climber (to prevent possible injury should something fall), but remain close by and ready to assist the climber the entire time they are aloft.
  6. When lowering the climber, belay them down slowly and always maintain control of their descent speed. If the person aloft is climbing down on their own (such as when using mast steps for example), those handling the lines must match the speed of line release with the climber’s descent.

The law of gravity is a wonderful thing – just remember that the effects are the same regardless of which side of the law you’re on, be it a water balloon gracefully arcing towards the unsuspecting occupants of an approaching dingy or a sailor that doesn’t follow basic safety procedures when going aloft.