Learn how to climb your mast solo or short handed and head aloft with confidence with this step by step expert guide from Pro Skipper and Tech Ed Fox Morgan

How to climb a mast solo: Step by step guide

If you’re here because you want to know how to climb a mast, then you are in the right place! The technique demonstrated in the following guide is tried and tested and used by the majority of professional sailors and expert Corinthian sailors too. This is for people climbing a mast where the halyard runs internally and passes out of the mast at the mast head via a mast head sheave or block. This technique is not intended for those climbing a wooden mast or where the halyard is mounted externally and passes via an external block. If you are unsure of any aspect of safety when doing any kind of work at height, please consult a local rigger.

how to climb a mast single handed solo

It can feel quite lonely up a mast with no-one to spot you from below. But it’s also a really nice feeling to be able to get the job done.

Solo Mast Climbing Technique

  • Wear appropriate clothing. We recommend close fitting clothing that wont snag on anything. Also protect your shins.
  • Consider wearing body armour if going up the mast at sea. It’s very easy to be slammed against the mast and crack a rib, which will definitely spoil your day.
  • Wear a helmet if you are in a rolling anchorage or underway. A BMX, kayak or dedicated climbing hard shell helmet is ideal.
  • You should be fit enough to be able to lift your own weight with one leg in a foot strap and one arm on an ascender.
  • Assemble the climbing gear like this:
    equipment diagram for solo climbing a mast
  • Attach 2 halyards to the mast foot area.
  • Attach prusik line to the halyard or line you are using as a backup safety.
  • Attach Ascender and GriGri to the main working line/halyard.
  • Clip on harness.
  • Double check all carabiner gates are locked closed and nothing is cross loaded.

How to climb a mast now you have all the equipment in place

  1. Slide the ascender as high as you can while standing.
  2. Pull up on the lazy line to pull the GriGri/belay device as far up the line as you can, as high as it will go while you stand on deck.
  3. Sit back into your harness and watch the GriGri articulate (if you are using this device) and see it grip the line.
  4. Make sure your foot is in the footstrap.
  5. Slide the ascender as high as you are able to.
  6. Grab hold of the ascender handle and pull yourself up so that you are standing in the footstrap.
  7. Take in the slack on the GriGri/belay device pulling it up the line as high as possible, to meet the bottom of your ascender.
  8. Sit back down again. watch the GriGri articulate again and watch for any snags or anything that doesn’t look right.
  9. Slide the ascender upwards again as far as you can.
  10. Repeat this process to rappel as far as you want up the mast.

Remember to keep sliding your prusik line up as you progress. This is your backup if the main line fails.

Ascend at your own pace.

You will swing about a bit. You can use your spare non-footloop leg to help grip the mast and steady you from swinging about too much. A couple of quick draws can be handy for holding you in place while you stop to work.

climbing a mast solo caution don't wind the ascender to the top without a gap

Beware of the need to leave a small gap above the ascender to allow it to be released from the line. So don’t go hauling it upwards slamming it into the underside of your masthead overhang. You’ve been warned!

When ready to descend, double check all of your lines and carabiners.

  1. Sit back on your GriGri or belay device, ensuring it holds you without slipping and remove the ascender from the line.
  2. Close the ascender gate to avoid getting spiked and hang it from your harness.
  3. Wind up the foot strap, tuck that away. You don’t need the footstrap anymore but you also don’t want it to get snagged on anything on the way down.
  4. With one hand on the lazy line,  ease back on the GriGri lever or belay device with the other hand to gradually release the friction on the line you are sitting back on.
  5. Feed the lazy line to control your speed of descent. You will start to slide down the line.

REMEMBER to slide your prusik line down as you go!

Take it slowly and control your descent carefully. There’s a lot to get snagged on as you go back down the mast.

Use your legs to grip the mast if the boat is moving around a lot.

How to climb a mast double handed

You have a few options.

  • A harness combined with bosun’s chair for a lengthy time up in the air or just a harness for a quick trip.
  • I prefer a hard seat bosun’s chair so I can sit back in it for a rest when doing lengthy jobs, such as feeding lines or wires down the mast. A harness is secure but can easily nip off circulation to a leg when hanging around for a long time. Foot loops can also help to take pressure off or allow you to gain a little height above the mast head.
  • Agree on hand signals for up and down winding.
  • Have your co-skipper wind on one winch while you slide a prussic line up the second secure line.
    Alternatively they could wind up one line then take up slack on a second winch with the safety line, as both can be attached to your bosun’s chair or harness, but this means your crew mate will be running between lines and this runs the risk of mistakes, cross winching, or tangles or worse, accidental line release.
    A prusik on a static line attached to mast foot while you are winched up on another line is a much safer method for two people.
  • For security when you are working aloft, make sure your co-skipper locks off that line on the winch to either a cleat or double back to create a locking turn. Don’t just rely on a clutch.
  • When they ease you back down the line, remember to hold your prusik line and knot as you go. This will help to hold you steady but also allow you to stop your descent quickly if you need to.

how to climb a mast double handed

How to climb a mast fully crewed

Use two lines, one per winch and you have a lead wincher for the main number one line and a second line tailer, taking up the slack on the safety line.

If you have enough crew, have someone as a designated spotter to relay messages to the prime wincher.

  • If you are unsure of the safety and condition of the lines, make sure you have a safety backup or mouse a new line through if there’s doubt over the condition of the line you are using. This might not be possible if you have a broken halyard already and the reason you’re going up is ton put a new one in!
  • Always go up with two lines.
  • Always wear footwear.
  • Use padding and head protection if there is a risk of you swinging about with the boat in motion.
  • Tie your own knot to your bosun’s chair or harness if being winched. Do not rely on the shackle or sail crimp to secure you.
  • Lanyard on/secure all tools
  • Use a mobile phone with hands free set or a pair of handheld vhf radios on ships internal comms channel 15 or 17 on low power/1w. [Calling protocol would be: Boatname – Alpha (for one person, eg up the mast) Boatname – Bravo (for another person, eg on deck spotting)]
  • Make sure your comms devices are securely attached and cannot fall.
how to climb a mast fully crewed

Spot the little faces looking upwards from the cockpit area. Your crew mates will seem quite far away when you are high up in the rigging. Make sure you have adequate communication in place for safety.

clipper 70 Old Pulteney

The bigger the boat, the more important comms devices become. Pace out the length of your mast on land, let’s say that’s 25m or 85 feet away away, now face sideways and try talking to someone at that distance. Rig up your phones or vhf radio on hand free use. Make sure comms devices are secured and can’t fall.

Don’t forget to use your own judgement when following our advice, or use a professional. Here’s our full disclaimer. 


How to climb a mast: all the gear I used in the demonstration

For climbing a mast solo you will need:

  • a climbing harness
  • an ascender
  • a belay device
  • 5 or 6 carabiners
  • a personal sling/daisy chain/loop
  • at least one foot strap
  • one prussik loop (you can make this from a 2.5m piece of rope/cordage)
  • total cost of kit used in demo approx: £288

For climbing a mast double handed or crewed:

  • a climbing harness and/or bosun’s chair
  • one prussik loop
  • total cost approx: £98

DMM Women’s Vixen Harness

DMM vixen womens harness - climbing a mast

This is the harness I used in the video for how to climb a mast. It is designed for women. I’ve used it for about 8 years and it’s still in great condition. I bought the large size to fit over my foulies or larger clothes, but it is a little big when wearing just light form fitting clothes. Ideally I would get a smaller sized harness for that purpose. DMM make these for men too.

  • 5 gear loops
  • breathable
  • 345g (xs) – 410g (large)

Price: £54

Buy DMM  Women’s Vixen Harness

Note: We may earn a commission when you buy through links on our site, at no extra cost to you. This doesn’t affect our editorial independence. Where indicated, items have been tested independently of manufacturers influence.

Petzl Ascension Ascender

petzl ascension ascender left and right hand models


This is the ascender I use on my own climbing gear and can be seen in my demonstration on how to climb a mast. I use a left handed version because I am right hand dominant and it’s easier for me to slide the ascender up with my left hand while pulling up on the lazy line with my right hand.

  • line size: 8mm – 13mm
  • 165g
  • left or right handed versions

petzl ascension ascender detail of jaw

Price : £46.76  /  $87.07

Buy Petzl Ascension left handed from GoOutdoors.co.uk

Buy Petzl Ascension left or right from AlpineTrek.co.uk

Buy Petzl Ascension from Amazon.com

Petzl Gri Gri +

Petzl Gri Gri + climbing a mast

This belay device can be used with all single ropes (optimised for 8.9 to 10.5 mm diameter ropes) and is equipped with an assisted breaking function. Suitable for beginner mast climbers to expert riggers. Feed your line in the GriGri, close it, add your carabiner to hold it closed and attach to your harness and you’re good to go.

  • line size: 8.9mm – 10.5mm
  • 200g
  • auto-locking

Price: £90.86 /  $129.95

Buy GriGriplus from Decathlon

Buy GriGriplus from AlpineTrek

Buy GriGriplus from Amazon.com

Grivel Mega K6N Screw Lock Snap Hook

Grivel Mega K6N Screw Lock Snap Hook climbing a mast


For belaying and rappelling. It is designed for use with both single and double ropes.

I use two of these in my solo mast climb gear. One is used from the bottom of the ascender to hold the footloop and personal lanyard and the other is used on the top of the ascender to work as a reduction turning point for the belay lazy line.

You need to be careful which way around your position this on your ascender to avoid your lazy line accidentally unscrewing it as you pull it through.

  • 7000-series aluminum
  • Screwgate
  • 78g

Price: £8.99

Buy Grivel K4n Carabiner from Trek Inn

Black Diamond Gridlock Screwgate Carabiner

Black Diamond Gridlock Screwgate Carabiner climbing a mast


Designed specifically for belaying, the GridLock isolates the belay loop behind its uniquely shaped gate, thereby keeping the carabiner in its proper orientation.

I use two of these carabiners, both from my harness. The anti-crossloading design is reassuring as the repeated loading and unloading of both the belay and ascender has a tendency to make standard carabiners rotate and there’s a high risk of crossloading when solo rappelling. They can be fiddly to get on and off but they add real peace of mind knowing how hard it is for these to cross load so you can just get on with climbing and dangling about up your mast.

  • Anti cross load design
  • 76g

Price: £18

Buy Black Diamond Gridlock from GoOutdoors.co.uk

DMM – Rhino Quicklock – Locking carabiner

DMM - Rhino Quicklock - Locking carabiner climbing a mast

For regular users of pulleys or GriGri like belay devices.

I use this carabiner on my prusik line. The horn stops the hitched on line sliding around the carabiner as it is repeatedly adjusted. The sprung loaded rotating gate release can be a bit of a fiddle to open but the advantage is that it can’t be accidentally unscrewed like the screw gate carabiners can.

  • Anti cross load horn
  • Quicklock gate
  • 81g

Price: £17.96


DMM Dyneema sling

DMM Dyneema sling

Dyneema has several advantages over traditional nylon webbing – it’s incredibly light and strong, less susceptible to UV degradation and is more abrasion resistant.
I use this sling as my personal lanyard between harness carabiner and the ascender. You need to find a sling that can be adjusted to your own personal reach length. I double this one over to give me the correct length.

  • 11mm Dyneema tape
  • 120cm
  • Strength: 22kN

Price: £9.90 

Buy DMM Dyneema sling from GOOutdoors.co.uk

Beal Nylon Sling

Beal Nylon Sling used as footloop for climbing a mast


A basic Nylon loop, ideal for use on a multitude of climbing uses, I personally use this as my footloop. I have two of them. They are cow-hitched onto the bottom of my ascender, one is tucked away and the other used for climbing. When I reach working height I use the second loop to stand up with both feet or to wrap one around the mast. It’s very handy to have two of these.

  • 120cm
  • 16mm

Price: £6.48 

Buy Beal Nylon Sling from GoOutdoors.co.uk

For more mast climbing gear you can have a look at our buyers guide

For a masterclass from Pip Hare on how to climb a mast safely at sea, you can read about that here

Further reading on mast climbing methods and equipment

How to climb a mast safely at sea – masterclass with Pip Hare

Mast Climbing for short handed crews

7 mast climbing kits on test

12 Bosun’s chairs tested

What happens when you dismast in the antarctic

Enjoyed reading Climbing a mast – best climbing gear & practical guide?

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