Advice on how to go aloft on your boat from Advanced Rigging & Hydraulics

For professional riggers, going aloft is routine - a daily necessity to inspect and maintain customer’s rigs. For most yacht owners, however, the thought of climbing the mast can be daunting. Yet at sea, it’s a skill every offshore sailor should have. Whether it’s checking a wind instrument or resolving a jammed halyard in mid-ocean, knowing how to go aloft safely and efficiently can make all the difference.

Below, the experts at Advanced Rigging & Hydraulics share practical, professional advice for preparing, climbing, and working aloft - whether in port or underway.

1. Preparation: The right gear and mindset

Before you leave the deck, start by checking your equipment.

Harness or Bosun’s Chair

Choose a high-quality, certified Bosun’s Chair or suitable harness that fits snugly around your waist and legs. Always check for wear, damage, or UV degradation - even if the gear looks barely used. For offshore conditions, a harness is generally safer than a chair, offering better security when in motion.

Use a safety tether and load-rated climbing carabiner and never rely on old or unverified gear.

Dress for safety and mobility

Avoid bulky or restrictive clothing. Choose durable, comfortable layers and strong, grippy footwear. If climbing at sea or in strong wind, rubber boots and a helmet are essential protection as the motion and movement will be significantly more than you experience on deck. 

Tools and essentials

Take only what you need, but make sure you have it all. A canvas tool bag securely fastened to the chair or harness keeps everything accessible and prevents tools from falling. If it seals, ensure it can be opened one-handed.

Attach each tool with a lanyard - a dropped spanner from masthead height can cause serious injury or damage to the deck. Bring a short length of rope to tie yourself off when you reach your working position.

2. On-deck preparations 

Going aloft is always a team effort. Ideally, have at least three crew members assisting - a primary wincher, a safety-line tailer, and a spotter. 

Lines and knots 

Use two separate halyards - one as the working line and one as the safety backup - and ensure both are in good condition. Avoid going aloft on an external halyard that utilises a hanging block, always choose a halyard that passes through (or into) the mast. 

Secure each halyard with a knot, not a shackle. A bowline with a half hitch is a reliable choice. Never use a splice of any kind, snap or key shackles. Tie the knot yourself and have another crew member check it before you ascend. 

Communication 

Clear communication between climber and deck crew is vital. On larger yachts, consider using hands-free headsets or open mobile calls - securely attached, of course. 

Always agree on backup signals in case audio fails. For example:

One knock on the mast: stop

Two knocks: hoist

Three knocks: lower

3. The Climb 

Hauling a person up the mast can be hard work. The climber should assist by employing rope-climbing techniques and using spreaders or mast steps to ease the strain on the winch crew.

Ensure several turns of the halyard are wrapped around the winch, and keep the clutch closed during ascent.

Watch for hazards

Both climber and deck crew should watch carefully for radar domes, lights, windexes, and antennas. It’s easy to damage equipment - or yourself - if you’re not vigilant.

 Securing and working aloft

Once at the working height, tie yourself securely to the mast using your safety rope. Position so you can move freely within an arm’s-length radius.

Work efficiently but never rush. Double-check fittings, work methodically, and never drop tools or parts - even small items can be dangerous from height.

When stationary, ensure halyards are cleated off securely - even self-tailing winches can slip. If no cleat is available, a towing hitch can add an extra layer of safety. And a spotter should always remain on deck.

 4. The Descent

Before lowering, check that halyards are free of kinks, that there are several turns around the winch, and that the clutch is released. The wincher should lower you steadily and smoothly, using a hand-over-hand motion. 

The spotter should call out potential obstructions on the way down - the same items you avoided on the way up can be just as hazardous coming down.

Once back on deck, leave enough slack to untie yourself safely and stow all lines properly.

 5. Practice makes perfect

Confidence comes from familiarity and repetition. Practice going aloft in calm conditions alongside before you ever attempt it at sea. Establish a standard procedure with your crew - who handles which winch, what the signals mean, and how to communicate clearly.

 And above all, remember: if you’re in doubt, consult a professional rigger. They can advise on your equipment, technique, and safety plan - giving you the knowledge to act confidently when it matters most.

 Going aloft is one of those seamanship skills that demands respect, preparation, and teamwork. For world cruisers, it’s not just about fixing problems - it’s about self-sufficiency, safety, and keeping your vessel ocean-ready.

With proper preparation, reliable gear, and good communication, climbing the mast becomes less of a risk and more of a routine.