When trying to answer the question, of how to use bolts in an area of natural beauty. What goes into a removable anchor system that works? The Petzl 12m Coeur Pulse Anchor seemed to fit my cause. A removable anchor system could be a possible solution to this highly debated and emotive topic of bolting.

To some extent, exploring this problem has helped develop areas of canyons that were once overlooked and classed as dull or unusable, therefore leading to a more enhancing experience in the canyon.

So how do you overcome the age-old issue of how to use bolts in an area of natural beauty?

Read on…

The Removable Anchor System As A Primary Anchor

what remains after the removable anchors have been removed

The problem I was facing was how best to protect clients using a primary bolted anchor system in a canyoning environment. The issue was more about protecting clients in areas that could have dangerous consequences, but would be quickly overcome by an instructor or guide with the right knowledge and experience.

To some extent, exploring this problem has helped develop areas of canyons that were once overlooked and classed as dull or unusable. Thus enhancing the experience for the client, but not necessarily for the instructor or guide. Anyway, it’s always about the client - right?

So how do you overcome the age-old issue of how to use bolts in an area of natural beauty?

As there is a distinct distaste against bolting by particular communities in certain areas, there lies the issue of how do we, as individuals and communities, overcome the problem and move forward. Secretly everyone wants bolts, but nobody wants to see them or admit to placing them.

The Coeur Pulse Anchor from Petzl seemed to fit my cause. I should point out that there are two types in Petzl's’ range - the 12mm Coeur Pulse and the 8mm Pulse removable anchor (Temporary 8 mm anchor for caving). I have only used the 12mm version, and this is what I am referring too in this article.

The Removable Bolt

Two new 12mm Coeur-Pulse removable anchors

On first inspection, this removable bolt/anchor feels fairly weighty and chunky and, at 140g, you know that it’s going to add some considerable weight to your pack, especially when you are carrying several of them. I assume that is why Petzl have produced the 8mm Pulse version for caving. Nonetheless, in the hand, they feel like they mean business. They are easy to use in the rock, and once you get used to which way to lock and unlock, they are reasonably easy to operate. Whilst the visual look is chunky, it does have some intricate mechanism that needs care.

To add to this piece of PPE rated kit, it looks shiny and colourful –   who doesn’t love a good bit of shiny kit!


So, What goes into a removable anchor system that works?

The placement is crucial, and the key to good success. One of the critical thoughts I considered was:

That good old adage - The ‘What if?’

If I drill a hole and it turns out that a more permanent fixture would be a better option, what would I do?

Obviously I now have a 12mm hole, where I need something to fix in its place. There are options, but I’m not going to cover them here. However, it is reassuring to know there are options.

In the canyoning environment, the pulling forces on an anchor are not always in a nice convenient place or where a straight downward pull can be achieved. The pushing and pulling forces (hydraulics) of the water can have an undesired effect on someone new to canyoning and abseiling. Therefore, some careful thought definitely needs to be considered to ensure the best placement.

I played around on some rock with different drills to see the results. I found that a light drill had more bounce and movement in the hole, especially at the beginning, which is the critical part; whereas the heavier impact drill, drilled a straighter hole.

The critical fact here is that you want a true round hole, which continues in a straight line.

It is worth mentioning that when I was experimenting with drills, I was standing on a flat platform with no structures or objects as a hindrance. These are not the ideal conditions you get in the canyoning and climbing world. This is something else that needs careful consideration as trying to drill a straight hole while hanging around on ropes and not having an adequate drill up to the task is a recipe for disaster.

Four Cutting blade drill bit

masonry drill bit with four cutting blades

Having spent decades in the building industry, I know that trying to drill a hole by hand which is true, straight and on target, can be tricky indeed. Petzl recommends going with a 12mm drill bit with either three or four cutting edges to a depth of 65mm, I would suggest using a good 12mm four cutting edge drill bit only. Yes, they do cost a little more, but the difference in drilling is vast. You can shop around for cheap ones but how many cheap drill bits are you going to use before realising one good drill bit was the way to go?

An excellent point to take special note of, is that a half-inch drill bit is not 12mm and is too big. The result would be that your newly placed anchor will have NO PULLOUT RESISTANCE.

An anchor can cost anywhere from £30 to £50, so get the right tools for the job, then you can feel happier when your life is hanging on the anchors.

It goes without saying that all usual considerations should be observed for bolt placements, i.e. rock condition, angle of pull, how close it is to the edge of the rock, redundancy by using two anchors and the flatness of the area for the plate to sit, etc. etc.

Removable Anchors Placed What Now? 18 Months On

Over the last 18 months, I have used the 12mm removable anchor/bolt in a canyon environment as the primary anchor system in critical places. I have also used the anchor for deviations. I have to say that I have been happy with the overall performance of the 12mm Petzl Coeur Anchor. Mind you, I treat the anchors as if they are made of gold: carefully placing them in and taking them out (which is also for other reasons that will become apparent later), drying them and attending to the maintenance afterwards. To clarify what I mean by maintenance, as a peice of PPE equipment I am checking to make sure:

General Checking and Maintenance

  • The anchor is not bent or twisted
  • Free movement of the working parts
  • No grit under the flat and expansion end plates
  • Check for wear and tear

These checks are no more than what would be required for the

checking and recording the use of PPE.

It is absolutely worth taking the extra time when placing the bolt in the hole, especially if the pulling direction and plate seating are critical - come to think of it, it’s all critical.

I have noted that continued use of the same hole is producing some changes.

The neck/rim of the hole appears to be widening, or more to the point there is a slight chamfering to the neck/rim. The result is now more movement in the plate. I am not talking lots of movement, definitely noticeable but not alarming. I cannot say whether:

  • This is due to the continued placement, as I said, I am cautious when placing the anchor (plugging it in).
  • Water erosion is playing a part, or just the general weather conditions are having an effect on the rock.
  • The pulling forces, and yes sometimes twisting motion, all be it minuscule, but over time is playing its part.
  • Other users 

  • I guess you could draw a conclusion that all of the above are having a role to play in the wear and tear of the neck/rim of the hole. Personally, I think it is due to the forces that are being applied, which in turn move the anchor. That is why I place them carefully to try to negate the wear on the neck/rim of the hole. As of yet, there has been no alarming movement or degradation of the rock, and eighteen months in I am still happy.

    I have noticed that if even when placed carefully, twisting forces can still occur, scary-sounding I know, so is watching it happen. This usually occurs when a wider or offline abseil occurs. The pulling force on the central point of the equalised anchors shift slightly, this is when the visible twisting occurs. Ever so slight, but still noticeable.

    I have used other systems to equalise the anchors and to allow for movement. However, I am not convinced what would happen to the remaining bolt, if one was to fail, resulting in the other being shock loaded. It is worth noting that, after removal and inspecting the anchor, I have not found any residual distortion, so I am guessing that there is an amount of inherent tolerance.

    alternative equalisation of removable anchors

    Slugs And Plugs

    One of my main concerns regarding this removable anchor is what happens if the holes become blocked. My initial thoughts were more concerned about people blocking it up, happily that has not happened yet - so their impact is unobtrusive. Which is excellent, as I would hate to get into a position where the reliance of anchors is needed, whether fixed or removable, only to find they have been tampered with or filled in.

    My Wildest Dreams…

    Never in my wildest dreams did I envision a situation where a slug would be the biggest problem. Picture this, you get to your abseil point, you place your removable anchors, noting one was a bit stiff going in but nonetheless all is fine and dandy. You rig the abseil/rappel, equalising the the anchors. Your group abseils down fine and all is looking good.

    Then it’s time to pull out the anchors and go. Ha, ha! Well, the bolt that was slightly stiff going in was due to a slug at the back of the hole. Now, having plunged the bolt into the slug and removed any air I have created a vacuum. That’s ok I hear you cry, well I replace a carabiner and sling on the anchor. I begin to pull and it will not come out, a quick check to make sure I have actually released the anchor. Now two of us begin pulling, either the slug is in a mood and has decided he isn’t letting go of this object, or the vacuum is more significant than two of us can pull. So now three people are pulling. Eventually the anchor pulls out, the squelching noise of the slug and air going into the hole can be heard.

    You can definitely say that I am far more careful about what is in the hole before placement. Believe you me there are many slugs around, so don’t say you haven’t been warned.

    animated depicting a slug eating a removable anchor

    Overall, other than this tale, I have not had issues where the hole is blocked or has grit or other critters in it that could affect the placement. There has been water in the hole, but this does not seem to affect the release afterwards.

    Unofficial Testing

    I have been unofficially testing the bolts, or more to the point observing what happens under specific loads. I have two anchors that are equalised with a sling and used for abseiling in a safe environment. The rope is semi-static, so not much bounce in the system. There have been up to three people either abseiling at the same time or resting on the anchors. The anchors are not in their ideal position due to the nature of the area, so a lot of the pulling force is placed nearer the axis of the bolt. On observation, there is no more movement or hint of pulling out, than when one person is abseiling on the system. Arguably there will be more forces in play than the eye can see, especially when three people (approximately 250 kg) are pulling, swaying and jumping on the system, however, the anchors and hangers are coping really well. Hopefully, in the future, I will add some load testing.

    12mm removable anchors in use on a small rock out crop

    Removable anchors on a little rock out crop

    Burr Necessities

    One of the bug burrs (pardon the pun) I have with the metal hangers on the anchors is that they still mark the carabiner, not enough yet to create a burr in an alloy carabiner but enough to notice. My thoughts around this issue of carabiners and metal hangers are to use quick links or metal carabiners. Great in theory not always practical in reality, but best to be aware that the issue exists.

    A rope under tension and travelling through a carabiner with a metal burr is only going to damage the rope, big time.


    For me, the main issue with the anchors isn’t the anchor itself but more to do with placement and the hole. The anchor is an excellent piece of equipment and has its place in the outdoor industry. It does, however, come with some of the following downsides.


    • The cost of the anchor, especially if you require several of them.
    • Drill bits cost more than the standard drill bits.
    • You need a good straight round hole.
    • You are not always in the right place or on a platform to drill the hole.
    • They are big, heavy and bulky pieces of equipment, especially when several are in use.
    • Real consideration needs to be given to the last man who has to come down. 

    Conclusion on 12mm Coeur Pulse removable anchor system

    In conclusion, I will continue to use the removable anchor system. I feel very confident in their design. They currently appear to be a robust and durable piece of PPE rated equipment, and so far they are performing as expected. So with the correct care and placement, I’m sure there will be more time spent using the removable anchor system.


    • Robust and durable piece of PPE
    • Chunky, which makes you feel confident in their use. 
    • Easy to use.
    • On the anchor, you can physically check to make sure the hole is not too big.
    • Made with stainless steel
    • Leave very little or next to no visible mark.

    This is not an attempt to cover the ethics of bolting or whether bolts are best left in place if holes are going to be drilled. It is more of an understanding of the placement of a removable anchor system, alongside its durability with long-term use.

    Leave a comment and add to this review.

    8 thoughts on “What Goes Into A Removable Anchor System That Works”

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