A proper way to climb a mast?!

Pete the Cat said:

Key point to me is to take the time for prep so that you think through everything you need and make sure everything is accessible when in the harness. I leave a pail on the deck for bringing up tools and taking things

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Amen. I've been up the mast a few times in the past month. Seems it takes at least an hour of prep each time before going up. When working near the top, I've found it helps greatly to hang a small diameter rope with many loops and clips on it to attach tools and parts to while working.

I'm a big fan of prussiks. My new rule is to use 3 lines (1 primary and 2 safety) with prussiks attached. To accommodate this, I hung spare climbing-lines from the masthead, and I loop a climbing-line around each of the spreader brackets. I also carry a spare pair of chest and foot prussiks. Now when I go up, I can completely unhook from any one climbing-line (while still having 2 other safety prussiks attached) to facilitate moving from left-to-right (becomes an issue when the forestay/backstay is blocking your passage) or from the front-to-back around the mast.



On smaller lines like halyards, I triple-wrap the prussiks, but on the big, beefy dock lines I've hung, a double-wrap gives plenty of bite and is easier to slide over the line.

G Kiba said:

I found comfort in having a system that puts less of my well being in the hands of a helper and having a redundant backup safety line that is somewhat independent of the primary equipment. In other words, removing/reducing the "single point of failure" if you don't count the mast falling down. I use a 4:1 rescue pulley system (used to raise and lower litters from high places). That, and a standard climb's prusik attached to a spin halyard and a secondary attachment point on my climbing harness. The 4:1 allows me to pull myself up while the helper tails the line that passes through a block on the toerail to a primary winch. The secondary safety can be lowered by the helper if I am not able to slide the prusik myself by lowering the spin halyard. Instructions are given to the helper prior to acending.

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I believe this system is also known as a Gantline Setup. Most of the riggers that I've seen around my area use this system with a prusik attached to a secondary line that is tied off securely - usually another halyard. This is the system I want to use in the future. I've been up the mast a few times lately but even though I'm not a heavy person, it still seems like a lot of work to hoist me up to the top of the mast.

I have been following this discussion with great interest as I am due up the mast over the winter for some light and wind instrument issues. Being a 28+ the forestay attaches about 8 ft short of the masthead so using the foresail halyard is a non starter. There is only one line that goes up the mast, the main halyard, and it is internal on the downhaul. Then there are the shrouds. two points of attachment each side of the mast, the spreader arms and the forestay. This whole arrangement makes it a major pain to efficiently get past and up the mast. In the manner of Kiba and Pete, I plan to use a 2:1 arrangement where the first block it taken to the masthead by the main halyard and the second block is attached to my harness. I can have an assistant haul me up using the mast mounted winches for the mainsail or foresail or I can haul myself up and use the bos'n chair method of tying the line off (much like we did in the navy). A form of safety line or system is what I am working on now. The first thought is to prussic directly around the mast to my harness and change it's position each time I meet one of the obstacles listed above. Has anyone out there done that?
Of note for a off the wall way up the mast I found on a youtube site Wind Hippie, a young woman sailing Maine into the Pacific solo. She just shinnies up the mast like climbing a pole! I'm a tad too old for that.
We also had a major yacht into Victoria last year (200 ft long) that had a bucket "elevator" that went up the mainmast. This is my preferred method but I can't afford the boat.

there's been a lot of good conversations on this topic. Here's another one that includes some more climbing rig examples:

Second Star said:

The first thought is to prussic directly around the mast to my harness and change it's position each time I meet one of the obstacles listed above. Has anyone out there done that?

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A prussik likely won't get any "bite" on the mast, and any slipping that results will generate heat which is bad for the rope. Look at a klemheist knot made with webbing. The webbing will likely grab better on the mast's hard surface.

See approx. 4:30 into this video
I used to use a klemheist on a 36 or 48" runner (climber's webbing loop) as a safety, once I got above the upper spreaders. I figured it would at least arrest my fall as a last resort. But, if you think it through, that's still problematic. Sure, you're alive, but if you're hanging by your last resort, that means you can no longer descend (with or without help), nor can anyone else ascend to help you down (and, you may be injured). That means your only options are:

1) A helicopter rescue (as I don't think fireman are going to climb a mast that's just experienced the multiple failures that put you in the position you're in). Or,

2) Hauling up a bag from deck level with more climbing gear. I.e., another line you can descend on, a carabiner to hook that line to your existing (or an added) Klemheist, and a pair of foot and chest prussiks to descend with.

It's well worth running through all the worst-case what ifs ahead of time.


Runner & klemheist around the top of the mast (wrapping it over the other lines will give the knot more to bite into).

Many of you will remember that I wrote an article for Good Old Boat magazine years ago on mast climbing techniques. Pick whatever works for you, but please, do have a back up of some type!

A few years back a rigger climbed my mast just like that but he didn't even use a safety anything. I stood in amazement. And fear.

This discussion makes me feel better about all the gear i take up with me. I was thinking I looked like a dufus, clattering around decorated with anodized gear like a Christmas tree compared to the bare bones shinny style climbers. But I didnt start tree climbing again until I'd learned and practiced switching climbing lines and descent gear at low level, and then practiced that at height, before tackling the mast. Always have at least a plan B and C. IMO, a mast is harder, in that trees have bark that grips lines well, masts are slippery. Trees have generally wide angled forks and branches that can help you, while masts have thin, close angled shrouds and stays that always seem to trap you.

I also appreciate the comment about not trusting the turning blocks at the collar, I totally overlooked that.

If I have a helper, they follow me with another halyard on a winch as backup. If not, a backup line clipped to a webbing loop that is cow hitched around the mast and fastened to my climbing saddle, and can be pushed up as I go, unclipped and re hitched above spreaders, etc as needed. It isn't a completely hardened attachment and likely to slip a bit if catching you in a fall but then plenty of injuries can happen from the shock of arresting a fall, and the main objective is to not take the loooong fall, so I think slippage for the backup isn't necessarily a bad thing. I'll take a broken rib or nose over a broken neck.

FWIW, I climb on a Hitch Hiker 2 ascender/descender with foot and knee ascenders, and use a Petzel I'D S as my backup descender, which can also be rigged at the base (base tie) so if unconcious, I can be lowered from there, without anyone having to climb up to rescue me. That requires an extra long rope, so theres enough to go from the deck, up through a pulley attaced to the halyard, back to the deck, and enough after that for lowering, so 3x the mast height.

If incapcitated, a rescurer can lower you by operating the descender's lever. The same precaution could be done with a deck winch, just takes a longer rope. And, then you could still take a backup line and descender with you so you could also self rescue from a main equipment failure.

An advantage to that could be the possibility to also raise an unconscious climber up off an obstruction with the winch, an otherwise horribly complicated task.

More FWIW, for scheduled work, I climb on a decent entry level saddle for the comfort and security. For emergencies, I carry a rock climber's version on the boat.

Last FWIW, fear of heights is a big deal, people can need rescuing from getting frozen by it. Having real, properly rated climbing equipment is essential. Honestly, it would take a tow truck to pull me out of a tree and I count on that. Practicing with it low and slow, long before attempting heights, and doing it often enough to be proficient in its use is also required.

Fear is crevice corrosion for the brain and things in there will snap if you haven't worked on your mental game as much as your technical one. You need a mental toolkit handy to sort through when something unexpected happens, anxiety starts to creep in, and your basic self assurances suddenly don't cut it.

Unless you're one of those fearless folks that are unperturbed by anything, in which case I dislike you already.

Kenneth K said:

Proper? I'd say a definitive "no" because I don't see any backup/safety line(s) at all. If the "helper" slips or lets go, or the winch rips off the mast, or any single piece of hardware fails, the climber is dead.

I went up my mast 4 times in the last 2 months. I go up using just prussik lines and a climbing harness. But I always have 2 backup prussiks attached to two backup lines while the primary prussiks are on the jib halyard. BTW, no helper required when using prussiks--one less thing that can go wrong.

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Back in the days when I would go up my mast, very similar process to Kenneth K, I had climbing ascenders and a harness, I would climb a halyard, and have two back ups thread through a figure at descender for safety.

A note to add about prussiks for climbing life support, per Kenneth's comment, descent on a prussik will generate heat, a lot in most cases, so make sure you use the type of heat resistant line made specially for that use, and also of a type and size to work smoothly with the climbing line you're on. If there isnt at least one other friction generating component in your setup, prussiks can be dangerous.

I learned about climbing with prusiks in a mountaineering course I took in the 2000's. The mountaineers were big on always using a chest loop-- a loop of webbing draped around the shoulders, crossed in an X across the back, and connected with a carabiner in front of the chest (the green loop shown below). The upper prusik goes through the chest-loop carabiner on its way to the climbing rope. This way, during a fall, the torso is pulled upright before the fall is fully arrested by your waist harness.

I always use a chest loop when climbing the mast. Not only would it keep you upright during a fall, but you can also tie it off to the mast to hold you upright (i.e., something to lean back against) instead of relying on your abdominal muscles to do that for an hour or more at a time.


Blue = climbing rope
Yellow = harness prussik
Green = chest loop

As a follow-up to my previous ref - using a prussic loop on the mast, I tried a two wrap prussic knot with 5/8 3 strand nylon directly on the mast. No lines were captured between the prussic and the mast. I stood with my foot in the loop and jumped up and down numerous times and it didn't slip. The mast is painted over anodized and that may have aided in the grip of the prussic. I think this arrangement will do for my safety, especially once past the spreaders where no other lines but the main halyard (used to hoist the primary climbing line) exist.

After maybe a dozen trips up the mast I figured it was time to replace my primary prussiks as the the outer jacket was becoming slightly frayed.

$12 at REI for 20 ft of 6mm cord. Another thing to love about prussiks.

Not long after patting myself on the back for being all safety-minded and replacing my mast-climbing prusiks, I discovered a flaw in my double-backup climbing system--the harness itself. I was in REI, shopping for new equipment when, for the first time, I started reading the safety warnings on some of the climbing equipment tags. Turns out, steel and aluminum components, if not damaged, are considered safe forever, while fabric components--harnesses, slings, runners, etc. have a shelf-life. I was surprised that the climber's convention is to replace harnesses after 7 years, even if not used. For slings/runners, it's 10 years. Obviously, it's sooner for either if dictated by falls, wear, damage, etc.

When I got home, I checked that date on my harness. It said, "Made in Philippines -2010." Oops.

So yeah, on my next trip to REI I dropped $80 on a new climber's harness. This one was rated high on comfort and, after two uses, I have to agree.

I feel like I should reiterate, in case it has been overlooked by someone thinking about going to heights, prussicks are a position hold or fall arrest device, not a descent device. They are fine for going up, not coming down.
In recreational climbing, usually some type of rappelling device is used. In comercial climb/descent work positioning, the need to switch easily and often between safe ascending (no slack) and safe descending (controlled friction) dictates a more sophisticated device, that does not require switching gear while at height.
In tree climbing, if a prussick alone is used on a single rope, the rope is doubled and the additional friction needed to make it safe and controllable is provided by the tree or limb the rope is thrown over.
In recreational climbing, a fall is part of the task and is anticipated, so stretchy ropes are used to absorb the shock of a fall.
In commercial climbing, static ropes with nearly zero stretch are used and every measure is taken to prevent falls. Precise control of position is essential and an arrested fall is painful, injurious or fatal, to the climber, people below or rescuers.
After any fall, ropes and other gear is often discarded, as shock damage may not be apparent.
Simply dropping an aluminum carabiner on pavement might be enough reason to discard it.
Prussicks used for descent may be subject to intense heat and abrasion and should be made specifically for prussick use. You only need to have a prussick tie in get away from you once to realize how important that is, assuming you live through it. Never use a rope not intended for prussicks, for prussicks.
I highly recommend the videos by Nice Guy Dave, at Wesspur (and YT) for easy to consume, professional information about safe climbing gear and methods.
Do not try to educate yourself by reading labels. If you shop at REI, take the time to consult with their well trained sales staff, who will undoubtedly recommend proper gear and training in its use on their climbing wall. In fact, they should shoo you out the door if you tell them you're looking to do work positioning climbing on a mast and not recreational climbing on a mountain, which are entirely different things. I'm quite sure their legal teams are very clear about that.

Vtonian said:

...prussicks are a position hold or fall arrest device, not a descent device.

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It makes little sense that a device suitable for "fall arrest" (which would subject it to sudden and intense shock loading, friction, and heat) would be inadequate for measured, deliberate, cyclical loading, regardless of whether that loading results in the climber ascending or descending.

Vtonian said:

They are fine for going up, not coming down.

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I'm not sure how that passes the basic laws of physics.

Vtonian said:

I'm fact, they should shoo you out the door if you tell them you're looking to do work positioning climbing on a mast and not recreational climbing on a mountain, which are entirely different things. I'm quite sure their legal teams are very clear about that.

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Actually, I was assisted by two REI employees on two different occasions; The first when I selected my prusiks, and the second when I tried out the harness, by hanging from the suspended line in the store. During both occasions I discussed with the employees how I use the equipment to climb the mast of my sailboat rather than for rock climbing. With the second employee, who was knowledgeable climber, we had a specific discussion about the best way to tie-in both a primary and 2 backup carabiners (for prusiks) into the harness.

Kenneth K said:

I was surprised that the climber's convention is to replace harnesses after 7 years, even if not used. For slings/runners, it's 10 years. Obviously, it's sooner for either if dictated by falls, wear, damage, etc.

When I got home, I checked that date on my harness. It said, "Made in Philippines -2010." Oops.

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I'd take those date with a grain of salt. They put those numbers on for liability reasons. Most people don't inspect their gear properly if at all. My Sala and petzl harnesses don't have expiration dates on them on purpose. Just manufactured dates for waranty. It says on their website "if the stiching is good and there's no physical damage, it good" It's assumed that if you are wearing one then you have some competency or are certified

Elgyn said:

I'd take those date with a grain of salt. They put those numbers on for liability reasons.

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Yeah, I kind of figured as much. I still feel like I got away with something getting 15 years from it, said the guy who's finally replacing his 40 years old stainless steel rigging.

We do our E27 mast with a topclimber Bosun's Chair. It's got a pair of ascenders. Use the main halyard to raise the climb rope (it's a dynamic line so has some give to it). The main halyard is, as always, run through its clutch, then for safety 4 times taut around a sheet winch, before finally being tied off to one of our docking cleats, which is extremely secure.

We then use the spinnaker halyard as a safety line. Again through a clutch, then around the main winch on our cabintop. I tend the safety line as my buddy climbs, taking up slack as he goes. Upon descending, I release the clutch for the spin halyard, and let the halyard out as needed. Even if I were to make a mistake and release the main clutch, it's still secured to the sheet winch and the aft cleat, so it's not going anywhere.

This works rather well, and seems to be plenty safe.

@Vtonian: You seem to have at least a fair knowledge of rope climbing. I’ve had few hours of mountaineering training, and maybe a dozen mast climbs without incident. So, it’s bothered me that our views about descending with prusiks were opposed 180 degrees. I took a look at some of the “Nice Guy Dave, at Wespur” videos you recommended, hoping they’d shed some light on our differences. They did.

TLDR: The Nice Guy Dave (a professional arborist) videos, in addition to your comments;


all lead me to assume you are referring to the use of prusiks as a RUNNING-type friction hitch.

Conversely, the method I'm referring to (the Texas Prusik/Crevasse Rescue method, TP/CR for short) uses two STATIC-type friction hitches, which never allow the climbing rope to “run” through the hitch.

With that clarified, I’m guessing we'd both agree that:

• A STATIC-type friction hitch should not be used in a RUNNING-rope climbing system (for either ascending or descending).
• Since the STATIC-type friction hitches used in the TP/CR method are used in exactly the same manner whether a climber is ascending or descending, they are equally suited to either use.

The full story:

During a recent, long hotel stay, I watched two videos from Nice Guy Dave, and two from other arborists. The first thing that struck me was that Dave was wearing a $500 climbing harness (Petzl Sequoia) with about $2k in fancy climbing gadgets attached to it. He earns a living with that equipment and spends 30 hours a week in a tree, so I get it. He’ll also be happy to sell you that equipment at https://www.wesspur.com/ (the arborist’s REI?).

The second thing I noticed, in both Dave’s and the other’s videos, was that every time an arborist talked about hooking their “prusik” onto their climbing line, they pulled out a device that recreational climbers would typically call an “autoblock.” In all cases I watched, they used a separate (and sometimes, multiple) device(s) to facilitate the actual ascending/descending of the rope. The “prusik” or “autoblock” was only used as a backup device. As such, while they climbed or descended the rope, they “tended” the “prusik/autoblock” hitch so the climbing rope could freely “RUN” through it (tending” the hitch typically means “pushing” on its coiled wraps to prevent them from tightening around the climbing rope). The idea is, in the case of emergency or incapacitation, once the “prusik/autoblock” ceases to be tended, it bites into the climbing rope and becomes a “STATIC,” immovable safety hitch around the climbing rope (a position hold).

<Autoblock with Machard knot <with a Klemheist
Autoblock, tied with a Machard knot. If one loop of the Machard is put through the other loop on its way to the carabiner, it may be called a Klemheist. But names vary. A Machard knot is often called a French Prusik. And, Prusik seems to be used, generically, to refer to almost any kind of wrapped-rope hitch used for rope climbing.

In stark contrast to Dave, I’m a weekend-warrior mast climber. I’ll spend maybe 30 hours hanging from my prusiks, wrapped around my boat’s halyards, over the course of my lifetime. If $2k in equipment were the mast-climbing entry point, I’d be better-off paying someone else to go aloft. I just want to do it safely, with a minimal need for new gear. I use the Texas Prusik/Crevasse Rescue (TP/CR for short) method when I go aloft. When I learned TP/CR in a mountaineering class, they used the name “Prusik Hitch” to specifically refer to a double- or triple-wrapped version of the Cow Hitch.
Cow Hitch (doubled) Prusik (tripled)


But, the term “prusik” was also used to refer the rope loop used to make the hitch (the prusik loop), and the process of using the loops to climb the rope (prusiking up/down the rope).
Prusik Loops for waist and foot attachment. Apparently, the term "Texas Prusik" refers specifically to a prusiking system with dual, rather than single, foot loops.

In the TP/CR system, two prusik loops are used: one between the climbing rope and your waist harness, and the second between the climbing rope and your feet. To start, the waist(*) prusik is slid (while loosened and unweighted) up the climbing rope as far as it will reach. Then the prusik knot is dressed (the coils arranged neatly), set (given a light tug to start it biting into the climbing rope), and finally, weighted (by lifting your feet to let the waist prusik support your full body-weight). The single waist-prusik knot is now set, statically, around the climbing rope (as a position hold), and fully supporting your weight. Next, the climber raises his feet/knees towards his chest to de-weight the foot-loop prusik. Once de-weighted, the slide-dress-set-weight ritual is repeated with the foot-loop prusik. Once the foot prusik knot is statically set, the climber stands up in the foot-loops, which then support his full body weight (and, thus, de-weights the waist prusik). By repeating the slide-dress-set-weight ritual, one knot at a time, the climber inchworms (actually, it’s about an 18” move) his/her way up/down the rope. Obviously, it works exactly the same whether climbing or descending. The important differences from the arborist’s autoblock are that (a) the prusik hitches are, in themselves, the primary climbing device, and (b) the climbing rope is never allowed to “RUN” freely through the prusik hitches. In TP/CR, the prusik knot is weighted only after it is statically locked onto the climbing rope, and moved (slid) only when it is unweighted. And, since there are always two prussik hitches around the climbing rope, there is a bit of a built-in safety. Even if one knot were to inadvertently slip, that slip is arrested when either, 1) the slipped knot hits the second knot, or 2) the two knots get pulled out to the maximum extension of their loops

I don't think you'll hear many arborists talking up the TP/CR method—it’s way too cumbersome for someone who earns a living working in trees. And, consider that, for safety, a mast-climber hopefully performs the slide-dress-set-weight ritual, sequentially, on two additional safety lines while moving about aloft. It takes me about 20 minutes to climb my mast and about 15 minutes to get back down. An arborist (who could be working up at three times the 45’ height of my mast) can’t spare 45 minutes to downclimb. Considering he’s likely got 3 other workers waiting idle at the bottom, that would be three man-hours of lost work. He wants to zip down in a rappel-like style with an adjustable-friction, running-rope descent system in two minutes or less. But not me. I plan for jobs to perform on the way down—re-tape the spreader boots, caulk the fore-deck light, clean the mast track, add hardware, Tef-Gel some fasteners, etc. I’ve never seen the need to zip down the mast in SWAT-team like fashion. It does look cool though.

Hope this helps clear things up for anyone who might be considering a mast climb. And, please weigh-in with comments, corrections, or tips.

*Note: I call it the “waist” prusik because the lower end hooks to the carabiner on your climber’s waist-harness. However, as the prusik-loop rises from the waist harness, it should pass through a carabiner on your chest-harness before reaching the climbing rope. This chest-harness connection keeps your torso upright in the event of a fall. A chest harness can be made from a simple loop of climber’s webbing, crossed in an X across your back (the X can just be a twist, it doesn't need to be "tied"), one loop-end around each shoulder, and joined in the center with a carabiner. An example: http://www.chockstone.org/techtips/Chest.htm