Sunday, 27 December 2009

Climbing Wall in Spain


The recent 7 days of horrible weather made the decision to install a large climbing wall in the Spanish house very easy - fortunately a lot of the ground floor is taken by a massive garage.

The useable area in the garage is now smaller and the skelton of a reasonably sized wall is up and ready for the boards to be attached.

The building work was organised by Julio who runs the climbing wall in Torremolinos - his brother is a carpenter and together they have built a lot of home walls and a large part of the Torremolinos wall.

My little wall is 3.5m wide and 3m high with a few different angles built into it from vertical to 35 degrees overhanging - the idea is that it is not just a training wall but a coaching and instructional facility.

Thus I can use it not only for movement coaching, but also for teaching rope skills - threading belays, clipping bolts, resting...lots of things. Plus I am keen to have a small abseil / anchor station built into the wall so that all descent issues can be taught effectively.

Plus it will keep me fit...

It should be finished by Wednesday and I can't wait to play on it properly.

Saturday, 26 December 2009

Rock Climbing in Murcia + Almeria

The bad weather continues in Andalucia ( Malaga /Granada / El Chorro / Loja + Archidona are all totally wet ) and a couple of climbers have asked for more details on the climbing in Murcia.

Mula: The page is in Spanish, but all the info is pretty obvious. The crag is not easy to find and there is a bit of dirt track driving, but the map on the site is pretty good. The topo is OK and will give you enough to go at for a couple of days. The topo outlines the main sector "Ferrari" and the routes range from 6a to 7c (ish).

Cacin: There is less info on the web about Cacin. The link gives access instructions, but you will need to get hold of a copy of an old Desnivel for the topos.

The best weather service I have found for Spain is Meteoblue

Thursday, 24 December 2009

Storms in Andalucia


The long, long indian summer came to an end dramatically with the arrival of some monstrous storms that have battered the whole of Andalucia for 4 days now. There has been widespread flooding throughout the region together with high winds.

The bad weather was supposed to arrive on Saturday and unexpectedly having the weekend off I headed to El Chorro fully expecting to be using the Poema Roca cave as shelter; however the weekend was fine - a bit cold when belaying but great for red pointing.

I returned home wondering how the forecasters could get it so wrong and then bang - the storms hit and carried on for 36 hours - there is a lot of wet rock here now and none of the usual dry spots escaped. This is the first time I have seen this happen.

Normally St. Anton in Malaga and Los Vados near Motril are safe bets, but they were both hit by the rain. John and Becky from the BMC were in Chorro and phoned for advice for where to go - normally I could suggest half a dozen places for them to go, but this time I could only suggest Los Vados as a forlorn hope...Apparently even climbing in Poema Roca was not possible apart from a couple of routes.

The closest dry crags now look to be in Almeria / Murcia - certainly this is where all the Malaga and Granada climbers are heading. The favoured crags seem to be Mula and Cacin - both are brilliant. The crags in Almeria are not well known to UK climbers, but often offer great winter climbing - I did hear a rumour that Rockfax were planning a Murcia guide, although I am fairly sure the locals will not be too pleased about this.

It looks like I will head up this way as well to meet up with some friends for Christmas before coming back down for my next climbing course on the evening of the 28th - fortunately the weather looks like it changes back to sunny conditions in Andalucia on the 27th.

Sunday, 13 December 2009

Learn to Lead Course in March in Snowdonia


I am busy in Spain at the moment and it is looking busy well into the new year. I will be coming back to the UK on the 30th March for the summer season in Snowdonia.

I have been fairly lucky with matching people up on courses this season, but am having trouble with one particular course...

Paul would like to do a 4 day combined Climbing Outdoors / Learn to Lead Climb course in Snowdonia / North Wales between the 1st and 4th March. I can't do this course myself as I am already booked up in Spain on those dates, but I can arrange for one of our regular instructors to run the course.

Paul has climbed a fair bit before and wants to use the course to refresh his outdoor skills and learn how to lead on trad gear - if you are interested in sharing this course then please just get in contact with me and I will set it all up.

The cost is £290 for the 4 days and includes the use of all the technical equipment.

There are full details of the courses on the Learn to Lead Climb and Climbing Outdoors pages of my main Rock Climbing Company site.

Saturday, 12 December 2009

Choosing a Climbing Harness

One of the questions I am regularly asked is "What climbing harness should I get? / how do I choose and fit a climbing harness?" Last week I was asked twice for information on climbing harnesses - so I wrote a short piece that is on the Rock Climbing Company site in the complete version.

There are other articles there that cover other aspects of choosing and using climbing equipment.

Climbing Harnesses - Choosing and Fitting.

  • Background
All climbing harnesses sold in the UK (and EU) are tested to meet certain mandatory standards as set out by the European Union Directive 89/686/CEE on personal protective equipment. The EN standard within this directive that deals with sit harnesses is EN 813 (Full body harnesses are covered by EN 361)This directive sets out the conditions under which products may be brought onto the market, the manner in which they may be used by member states, and their free circulation within the European Community. It also sets out general rules pertaining to design and defines the certification procedure for equipment.

As far as climbers are concerned a key part of the testing requirement is that a force of 15kN (equivalent to a static load of 1500kg) is applied to the harness and it must hold that load for 3 minutes - so don't be worried about falling off in any new harness. It is one of the strongest parts of a climbing system.

A climbing harness is a core piece of kit for any climber so it is worth spending some time choosing one that fits correctly and has the features that you need.

Don't buy your first harness on Ebay or second hand - it is most likely that you won't have the experience to determine if it is safe and it is very unlikely that you will get the best combination of fit and features that you need.

Head down to a good climbing shop that has a wide range of harnesses and shop staff that climb. The shop should have some means of letting you hang in a harness so that you can check that the harness will hold you in the correct position in a fall /during an abseil. This also lets you gauge how the harness spreads the load / how comfortable it is.

Then spend some time choosing the best harness - the article below will look at types of harness, features and fit and should hopefully give you a few ideas about what to look for...


1. Types of Climbing Harness

Thus the first thing to decide is what type of climbing that you will use it for – this may sound silly, but each different climbing discipline is best served by a harness with specific features. The majority of climbers will not have a harness for all the different types of climbing, but knowing what features you will and will not need should mean you don’t make compromises in the wrong areas.

Centre Harnesses: Centres and groups want harnesses with a simple design, great durability and wide size adjustment amongst other things. Thus most popular centre harnesses are constructed from un-padded 44mm nylon webbing with a minimum of gear loops. Many have a high tie-in point because they are often used with children and this feature helps reduce the chances of children inverting (children have under-developed hips and a higher centre of gravity compared to adults). They are perfect for groups, but their limited features means they aren’t perfect for personal use.

Examples: DMM Alpine and DMM Brenin

Mountaineering and Alpine Harnesses: These harnesses need to be light, easy to put on when wearing big boots / crampons, have a wide range of adjustment to go over a multitude of clothing systems and have drop away legs for calls of nature. Ideally I prefer these harnesses to have 4 or more gear loops, although a lot of people use bandoliers in the mountains. They are normally worn over several layers of clothing and so do not need padding for comfort, in addition unpadded belts are lighter and absorb minimal water. There are two main styles – harnesses with fully opening adjustable legs and those that use a nappy design. Nappy designs tend to be most popular because there is only one buckle to do up/carry up the hill.
You will be using this harness with gloves so check that everything can be adjusted with gloves on. Features that are fiddly in the shop will be impossible to use on the hill.

Can you use the harness with your rucksack on? Is it comfortable or will the sack cause the harness to dig in? Stop you accessing your gear loops?

Examples: DMM Super Couloir and BD Bod (not the Alpine Bod which lacks a belay loop).

Rock / Cragging Harness: This is the harness for general summer cragging duties. It is probably the hardest design to get right because of the contradicting demands placed on it – it also (unfairly) increasingly unpopular as climbers have moved/been pushed towards fully adjustable harnesses.

The harness needs to be padded so that it is comfortable on stances and yet be lightweight and unrestrictive, so as not to hinder athletic movements. This is best achieved by using a sculpted waist belt that is wide at the rear and is then cut away at the sides - when designed correctly this should provide support in the small of the back and yet not restrict sideways bending. The quality of the foam padding is also important – there is no point in having padding if it collapses under load. Squeeze the waist and leg loop padding and see how it behaves - if is collapses easily then it is unlikely to provide much comfort..............

This is continued on the Guided Climbing page of the RCC site in the tab under the main text.

Thursday, 19 November 2009

Rock Climbing at Loja


I managed to redpoint the classic 8a at Loja today.

Vibraciones Positiva is a long 35m stamina route that features long reaches on mainly good holds - a couple of the reachs are really long and caused me a few problems - my feet keep cutting loose. See left.

The whole crag is in perfect condition after so much dry weather and its position at 1000m and northerly direction have made it perfect during the recent hot weather.

I have finally taken a week off because Simon came across to visit and it was great to climb together. He has gone back now, but I still have 3 free days before my next clients arrive and so am off to Archidona for more steepness.

It was also good to see Alison B, who came on a course last year and returned to Villanueva del Rosario last week to explore the area some more.

Chris and Ryan arrive on Sunday for a joint climbing course and it looks like the weather is going to hold on being good for them - after that I am fully booked until the 19th December and January is filling up fast.

Tuesday, 3 November 2009

Chilam Balam Cave - 8b

Very happy today because I managed my second 8b yesterday.

The route is called Golpe de Calor and is one of many fantastic routes in the Chilam Balam cave on the outskirts of Villanueva del Rosario.

The cave and surrounding area have proved very popular as the prolonged hot, dry season has forced climbers to look for shady, high crags. Chilam Balam cave faces north and lies at 1000m There were about 20 climbers at the crag yesterday - not bad for a crag where the routes start at 7c.

Golpe de Calor was equipped and first climbed by Bernabe Fernandez (Amazing roof climber and driving force behind a lot of hard routes in Andalucia) two years ago. Originally graded 8a+/8b it has settled at 8b - the grades are noticeably harder here than El Chorro.

The route is 30 m long with the the first 15 meters on tufas and crimps on a wall that overhangs 20 degrees, then a desperate roof on undercut tufas and slopey footholds with a gripper clip. The top wall is super technical with minimal footholds and a final insecure runout to the chains.

I found it quite hard because I could not get the kneebar rest below the overhang - I wasted a day trying to get my foot and knee to stick before deciding that I was wasting more energy than saving.

On my first redpoint attempt of the day I got past the top crux but broke a small undercut - I really did not think I would have enough energy left for a second go, but somehow managed to fight to the belay.

This was the 5th ascent after Bernabes, Javier Morales, Carlito from Malaga and Urban.

All in all a great route! Thanks to Carlito, Gonzalo and Urban for all the help and encouragement.

The cave has seen a lot of development recently and the climbing topo for the area is fast becoming out of date.

It has been a good season so far - I was worried that after 7 months of instructing clients on a variety of climbing courses with hardly a day off that I might not be route fit, but the evening sessions on my home finger board have paid off and being on the hill has kept me aerobically fit.

La Rubia looks good...

Tuesday, 27 October 2009

Dry Weather in Andalucia


I'm have been over in Spain for a month now and the weather has been amazing for climbing. I have been completely full on with courses and the warm weather has made it especially enjoyable, but the local farmers have a different view - they are desperate for water.

The photo on the left shows the effect that the dry weather is having on the olives. The olives on top are how they should look at this time of year, but a lot are looking like those at the bottom of the picture - underdeveloped and wrinkled.

Olives are a mainstay of the local economy and this is potentially a big problem. The town ajuntamiento has imposed a water ban between 0100 and 0600 to try and save water, but they really need some rain.

The warm weather means that the high crags of Villanueva del Rosario have been really popular with climbers from Malaga and Granada - the shady crags of La Ventana and Chilam Balam have been receiving a lot of attention and the hard routes have been falling fast despite the fact that the routes are quite harshly graded compared to the routes at El Chorro.

The spanish climbing courses are proving really popular and there I only have 10 free days between now and Christmas.

Sunday, 25 October 2009

Worn Carabiners



The carabiner to the left was sent into DMM for testing - I am not quite sure of its history, but the size of the groove that had been worn into the top bar is pretty impressive. DMM see bolt damage to carabiners fairly regularly, but this is exceptional.

The groove had eaten through 27% of the thickness of the bar and the volume of metal that had disappered was even greater.

I fully expected this carabiner to break under 10kN, but it actually acheived 26kN - greater than its rating when new.

It is difficult to explain this especially considering that a much smaller nick in a similar carabiner (see Mamba post below) caused a serious loss in strength. I don't want this post to encourage people to use carabiners in such a bad state, but rather use it as a pointer that there are a lot of variables involved in how and when kit breaks - some obvious and some that obviouslly are not.

DMM customers have asked in the past "how much wear and tear before I should reire equipment" - hopefully the last two posts show that this is a difficult question to answer.

It should be stressed that this carabiner should have been retired a long time before it reached this state.

The second image shows a 30 year old HMS from the days when DMM was called Clog and employed about 10 people. It had a rope groove that had eaten away 6% of the thickness of the bar. It made 24KN.

Thursday, 8 October 2009

Old Carabiners + Tapes - Breaking Strengths


Sports climbing carabiners get a hard life.

They are constantly subjected to short hard falls, clipped into sharp or badly aligned bolt hangers and ground against the rock. The tapes also get a hard life as they get grabbed with chalky hands and suffer harsh abrasion, especially as the run over the carabiners.

DMM recently received a couple of old Mamba quickdraws back that were over 10 years old and which the owner wanted tensile testing.

The quickdraws looked in reasonable condition - there was no bad visible fraying or fading on the quickdraw tape, although the ends had some mild fluffing where the tape had been caught between the rock and the carabiner. The carabiners functioned well and with a little lubrication would have been perfect. The metal was free from corrosion, although there were some sharp bolt marks on on of the straight gate carabiners.

The first Mamba we loaded up included the straight gate carabiner with 3 bolt scars on the inside apex. The tensile test started - at about 8kN it was obvious that something was going to pop early because you could hear the tape fibres starting to snap. This does not normally happen to around 18-20kN normally. The real surprise was when the straight gate carabiner suddenly blew out at just 13.6kN - almost half of its rated strength.

On examination it was obvious that the one of the bolt scars had created a stress multiplier that had then opened out the scar to create a full blown fracture.

The second Mamba blew out the tape at 15.5kN - about 60% of its strength when new. Once again it was obvious it was going to break early because the micro damage to the fibres could be heard starting around 10kN.

In a real world situation both of these Mambas would still have done their job - but they would be far less tolerant of stupidity or misuse i.e. connecting a short sling to the Mamba to hold you in position why you work a move and then slipping/jolting back onto it - this creates massive forces that can break new carabiners let alone half strength ones.

The slings blew early because they were old and some minor damage accelerated quickly to cause a complete failure. The carabiner blowing out early was surprising and probably worthy of further experiments because although the bolt scars were noticeable they did not seem excessive.

There is more information on climbing equipment at Rope Rescue Techniques below the main text and informatio on choosing carabiners on the Rock Climbing Outside pages - again below the main text.

Thursday, 24 September 2009

Corrosion in Climbing Carabiners - Corrosion in 7000 series Aluminum Alloys

Each year DMM receive back a few carabiners where the surface of the carabiner has corroded and exfoliated. Almost invariably these carabiners have been to Thailand (although DMM have seen similar corrosion from carabiners used in Hawaii). They are often asked for the reasons why this corrosion occurs.

Aluminum alloys are widely used in the manufacture of climbing products because these alloys can offer a high strength-to-weight ratio combined with good ductility and toughness.

There are currently 8 families of aluminum alloys and each family group is identifiable by the first number of its name. The families differentiate themselves from each other by their principal alloying elements:

Major Alloying Element

Series Identifier

None (99%+ Aluminum)

1XXX

Copper

2XXX

Manganese

3XXX

Silicon

4XXX

Magnesium

5XXX

Magnesium + Silicon

6XXX

Zinc (Magnesium + Copper)

7XXX

Lithium

8XXX

Unused

9XXX0

These main alloying elements impart specific properties to the alloy. These properties can be further modified both by the addition of extra alloying elements and processing treatments that occur during the production of the finished alloy product.

The vast majority of carabiners used in recreational climbing are made from 7000 series aluminum alloys with aluminum alloy 7075-T6 being the most widely used. 7075 describes the grade and T6 describes the generic heat treatment process used on the metal.

7000 series alloys have zinc as the primary alloying element together with magnesium. The further addition of copper to the aluminum-zinc-magnesium system together with small, but very important amounts of chromium and manganese gives high strength aluminum alloys that, although initially developed in 1943, are still the benchmark for use in climbing carabiners. There are stronger/tougher alloys on the market, but cost and productivity issues often work against them in a commercial environment.

Chemical

Composition Limits (Wt. %)

Si

0.4

Fe

0.5

Cu

1.2-2.0

Mn

0.3

Mg

2.1-2.9

Cr

0.18-0.28

Zn

5.1-6.1

Ti

0.2

Aluminium metal is a very active metal that oxidises very quickly. While this would be a weakness for most metals, this quality is actually the key to its ability to resist corrosion. When oxygen is present in the atmosphere or in the environment (in the air, soil, or water), aluminium reacts very quickly to form aluminium oxide. This aluminium oxide layer is chemically bound to the surface and it seals the core aluminium body from any further reaction.

This is different from oxidation (corrosion) in steel, where the metal oxide (rust) exfoliates, and constantly exposes new metal to corrosion. Aluminium’s natural oxide film is tenacious, hard, and instantly self-renewing. It is this combination of fast oxidation and a protective air-formed oxide film that enables most aluminum alloys to offer good resistance to most corrosive environments.

However the very alloying elements that make the 7000 series perfect for building carabiners make the metal more susceptible to corrosion. It particular it has been established that the addition of copper (2000 series alloys) and zinc/copper/magnesium (7000 series alloys) to the aluminum solid decreases the corrosion resistance of the alloy. This is due in part to the fact that the aluminum oxide film is now not consistent over the surface of the metal and contains oxides of copper, magnesium and zinc which can decrease its protective qualities.

In addition any metal ions passing into solution as a result of corrosion can then be deposited on the surface of the alloy and set up galvanic cells on the aluminum surface. This can dramatically increase the rate of corrosion.

However certain other factors often need to be in place to de-stabilise the oxide layer and accelerate the corrosion process, these include:

  • The oxide is not stable in acidic (pH <> 9) environments
  • Aggressive ions (chlorides, fluorides) may attack the oxide locally i.e. sea water
  • Certain elements (Ga, Tl, In, Sn, Pb) may become incorporated in the oxide and destabilise it
  • Contact with dissimilar metals including pressure treated wood (which contains copper) carbon steel and mild steel.
  • Heat

  • Sea salt (mostly sodium chloride) can help destabilise the normally protective oxide film, leading the localized attack (pitting). This happens because it acts as a facilitator for galvanic metal corrosion.

When the two dissimilar metals come into contact an electrical loop is closed, and the natural voltage differential between them causes electrons to flow. One metal becomes the anode (negative) and one will become the cathode (positive). This electrical circuit causes the anode to lose ions and the cathode to gain ions i.e. the more active metal dissolves. The copper is relatively inactive and the other metals in the 7075 alloy, including the aluminium base metal dissolve/change form. These adverse effects are magnified if the copper is out of solution at grain boundaries.

The most common form of corrosion on carabiners is pitting – small localized corrosion on the surface of the metal. Exfoliation corrosion takes longer to happen and is often more serious – it is a severe form of inter-granular corrosion that occurs along aluminum grain boundaries and causes delamination of the surface of the aluminum with white corrosion products forming between the layers.

Anodising can reduce corrosion in aluminum alloys by increasing the thickness and hardness of the protective oxide layer. The standard anodising process used on carabiners uses chromic acid or sulphuric acid; the anodising process causes a chemical transformation of the aluminum material itself to create a thicker than normal aluminum oxide surface layer. This layer is often dyed and then it is sealed by a secondary chemical treatment, normally immersion in boiling water.

Anodising does help a lot in reducing corrosion, but it is not an alternative to looking after your kit – if the surface of the carabiner is nicked or scratched, such as happens when a carabiner is loaded on a steel bolt hanger, then this will allow corrosion to potentially begin.

In this situation there is a galvanic cell between the steel hanger (even if it is stainless) and the carabiner. The situation is worsened by the large cathodic surface of the hanger concentrating the current flow through the small anodic area of the scratched anodize on the carabiner.

Keep you carabiners dry, cool, away from salts and away from acids. If you do climb by the sea wash your gear in clean, cool water and dry it in a warm environment naturally and lubricate when dry if necessary.

There is more information on a corroded quickdraw set on my web site - see Strength of Old Carabiners

Click on the tab below the main , central text.



Tuesday, 8 September 2009

Crib Goch


I recently was able to help a client fulfill a long standing desire to climb Snowdon via the Crib Goch ridge.

The weather forecast was fairly horrible with both high winds and rain predicted; the warm-up day was spent at Clogwyn Cyrau near Betws Y Coed rather than Tryfan because of the high winds in the Ogwen Valley. However at least we stayed reasonably dry there and covered all of the rope techniques that we would need on Crib Goch itself.

The following day was looking fairly grim as well, but at least this meant there were parking places in the Pen Y Pass car park.

It was fairly windy on the approach to the ridge itself with lots of low lying clag, but the wind died completely as we hit the ridge itself - perfect timing! The traverse along the famous ridge went very smoothly despite the rock being quite wet and slippery. The Pinnacles at the end of the ridge were climbed successfully before the wind hit us again on the strenuous hike up to the summit.

It was a long day out on the hill and getting late so we opted for the luxury of taking the train back down to Llanberis, where Simon met us for a quick trip back up the Llanberis Pass to the Pen Y Pass.

A perfect example of perseverance and hard work being well rewarded. It would have been all to easy to use the weather as an excuse to not try the ridge, but by taking it one step at a time we stayed safe, in control and were in the right place to make the most of the opportunity when the wind eased. A good day out.

Wednesday, 2 September 2009

Cross Loading Carabiners

There was a photo of a broken carabiner posted on UKC today via a link to York Climbers. The photo has now been taken down for some reason, but it showed a DMM Phantom wire gate with a buckled gate and the gate misplaced on the outside of the nose.

There was some debate on how this happened and speculation that trust in wire gates may be lowered. Simon at DMM had a quick look at how this may have happened.

"I have not seen a biner look like this outside of a test lab and so spent a bit of time looking at different scenarios for this happening. The gate had obviously been cross loaded in an uneven manner against a hard object and we looked at how this could happen. We tried to replicate the situation using different bolts in different orientations at different angles .

In theory the twisting force needed to damage the carabiner in this manner could be applied with poorly orientated (or loose) bolts if the carabiner at the bolt end of the quickdraw rotates 180 degrees so that the carabiner is upside down with the wire gate levering/pressing against the hanger at right angles. It is then possible if the carabiner is trapped/has restricted movement that the quickdraw sling can apply a levering action onto the top side of the carabiner and hence the wire gate.

I have tried to replicate this in the image above (a/apologies for the ring in the background, I did not have any plain bolts of this type on hand. b/The quickdraw is on the wrong way round- it just was easier to set up the shot with the tadpole holding the draw in place). The critical factor is that the orientation and shape of the bolt of the bolt facilitates the the biner hanging up and being trapped as the load is applied i.e. it happens much more easily in sheet steel bolts with small apartures that have twisted and sit 90 degrees out of position.

It is also possible to achieve this by getting another carabiner nose engaged in between the wires of the gate and a twisting moment then being applied to one of them whilst the other is held firm.

I hope that makes sense"

Personally I use Phantoms as my trad draws (weight), but use Shadows for sports (burly, keylock and fast to clip) - but then I'm lucky enough to have two sets of draws.


There is more information on climbing carabiners on my site in the tabs below the main text.

Plus there is more info on gear at the new Climbing in Spain site.

Saturday, 22 August 2009

DMM Torque Nuts - Why they work better...

There was an interesting conversation going on at DMM the other day about the new Torque nuts and about why they worked better than other large hexcentric nuts. The following is from a letter that the Torque nut designer, Graham Desroy, sent to Toby at UKC. Toby is reviewing the nuts.

"When I started the project I started with a blank canvass with the objective of designing a large nut to compete with the Wild Country Rockcentrics.

Obviously being old and having worked for Troll and HB prior to DMM I have gained a few pointers on the way. Interestingly my old Chouinard Hexentrics worked very well in the camming orientation with good expansion. The HB Quadratics despite looking somewhat odd offered an even better expansion in the camming orientation - Hugh was a very clever designer. The Wild Country Rockcentrics however scored because they looked a more attractive shape even though they didn't/don't perform as well.

The reason for this is that Wild Country changed the angles on the side and introduced a more continuously curved shape, especially on the convex sides. By doing this you lose an important pivot point from which the cam action is instigated.

What the Torque nuts achieve is a combination curves and pivot points which allow the nut to cam correctly. Also by carefully calculating the relative side angles the expansion range is increased. The result is a nut that not only looks good but maximises the camming expansion - this is especially noticeable in horizontal placements.

Attached is a spreadsheet which has the relevant measured data concerning the camming expansion and total range of each nut for Torque nuts and Rockcentrics. You will notice that Torque nuts have a significantly better camming expansion than Rockcentrics and also that our camming expansions overlap between sizes; Rockcentrics don't.

Also we achieve this in four sizes whereas Rockcentrics require 5 sizes.

The other major design advances are the trough in the upper face to protect the webbing.

Also the double slinging (Patent Pending) which allows the Torque nuts to be 'shorter' on the gear rack when 'doubled' compared to Rockcentrics, yet longer when extended into the 'single' sling mode. This not only makes the nut easier to carry but also saves on a quickdraw when extended. Following a trip to the Lewis sea cliffs last week I am just increasing the hole diameters very slightly as I speak as I want to improve the 'running' of the sling through the nut, - hence your sample set may be less smooth than future ones.

As regards strength we have rated all the Torque nuts at 14kn, whether the nut is used 'single' or 'double'. This is very conservative, some of the sizes are considerably stronger - it's all to do with wall thickness related to nut size and distances between the holes."

There is more information on placing climbing protection on my site:

Sunday, 16 August 2009

Choosing a rack of Climbing Equipment

I am often asked about what climbing equipment should climbers buy as they are building up their first rack, so I put together this short article that is taken from my climbing instruction website.

Choosing and Building a Rack of Climbing Equipment.

DMM Offset in a perfect flareLearning to climb outside means gaining many new skills; one of these is building an understanding of the extra climbing equipment that is needed when climbing outdoors. We are often asked what equipment is required in different situations, how climbing equipment should be chosen and how to build a climbing rack.
A climbing rack is the collection of hardware, slings and rope control devices that a climber carries to protect a route, set up belays and control the rope.

Inevitably when you start out climbing then your rack will have gaps in it and this will limit some of the routes that you can attempt, but building a rack around the kit that your climbing partners have and then sharing racks is good way around this problem.

In general the rack you will need will depend on the length of the route you are attempting, its difficulty, the rock that the route is made from and the specific features in the rock formation.

The longer the route then the bigger rack of equipment that you will need to protect it; harder climbs often involve less featured, blanker sections that need more small, specialist gear to protect them and different rock types favour differing types of protection.

The first trick is to build up a rack that consists of the right amount of the right equipment so that you can protect a wide spectrum of climbs and the second is knowing what to carry in different situations – carrying enough kit to safely protect the climb and yet not carrying superfluous gear that will just weigh you down. Common sense, checking out the route from the ground and versatile gear together with a big dollop of experience all play their part here.
A summer rock climbing rack comprises the following items:

  • Carabiners and Quickdraws
  • Passive Protection
  • Active Protection – Camming devices
  • Slings
  • Rope Controllers
  • Emergency Equipment

These are our suggestions for different situations:

Carabiners and Quickdraws

Carabiners and their associated quickdraws will make up a significant proportion of the weight of your rack so try to go as light as possible, but never compromise on safety or function. On long trad routes you will be carrying 40 to 50 carabiners and choosing lightweight carabiners can save you over a kilo.
Wiregate quickdraws with the carabiners slung on skinny (8-12mm) dyneema are pretty much mandatory for traditional climbing and winter climbing, but for sports routes burly keylock solid gate quickdraws on wide (16-20mm) nylon tape are still best.
The reasons for this are exemplified by a couple of the best carabiners on the market at the moment the DMM Phantom and the DMM Shadow. The Phantom is a superlight wiregate and the Shadow is a tough, solid gate:

  • Wiregates can be built to be lighter than solid gates. Thus the Phantom comes in at 26g and the Shadow 42g….and the Shadow is really light for its class.
  • Resistance to upward progress comes from both the weight of your rack and the drag of your rope(s). Lightweight wiregates slung on long skinny dyneema draws both weigh less and create less drag.
  • Wiregates also tend to have less gate flutter and freeze shut less easily than solid gates. Bear in mind that superlight biners such as the Phantom may not be ideal for winter climbing because with their light weight comes a smaller size and in winter handling small biners with gloves can be a pain.
  • Lightweight wiregate carabiners can be used for sport climbing, but the protection bolts on sports routes are made from steel and chew up aluminium carabiners too easily – badly made, badly positioned and badly placed bolts can cause biners to become scored, levered and generally abused. Durability, good handling and keylock noses are the prime characteristics to look for here – weight is still important i.e, the Shadow weighs 42g compared to the previous class leader the Petzl Spirit (49g) especially on on-sight attempts. The quickdraws are often wider nylon because this is easier to grab when dogging/working routes and drag is less of an issue because most sports routes are straight lines.

Badly designed Carabiners

In terms of strength the key strength is the gate open strength – don’t go for anything less than 8kN. Also ignore any carabiner with a large notch in the nose that can catch / hang up on wires or tapes. When loaded in this position most carabiners will break at 3-4kN and most falls will generate this amount of force.

Don’t bother with accessory biners for racking nutkeys or chalk bags – get something useful that could get you out of trouble one day – put the nut key on a full strength, light wire gate carabiner and put your chalk bag on a length of 5/6mm cord that can double as a prusic loop.

Screwgates are relatively heavy - often at least as twice as much as a lightweight wire gate – so choose carefully. You will need a HMS/Oval for your belay device, a nice HMS (or two) with plenty of internal space to act as central connectors and some smaller, offset D screwgates to link critical pieces together.

It used to be suggested that you use doubled-up, back to back snap gates instead of screwgates because this is lighter, but that is no longer the case i.e. DMM Phantom SG at 41g.

Passive Protection - Wires and Nuts.

Nuts are your core protection so don’t skimp – go for a versatile rack of nuts that offer you the maximum amount of placement options. The best mainstream nuts are:

  • DMM Wallnuts
  • (Anodised) Wild Country Rocks (not the Classic Rocks)
  • Metolius Superlight Curve Nuts
  • DMM/HB Alloy Offsets

These all have complex shapes that allow a multitude of placements – not only do these allow main axis and sideways placements, but they fit flares better, cam into marginal placements and keyhole into pockets.

Basic square shapes such as used on the Zero G, Black Diamond, Camp and Kong nuts are just not as good. Always also check the weight of the nuts you are looking at because there can be a significant difference between solid wires and those that have cut away sections i.e. WC Anodised Rocks v WC Classic Rocks. Also check that the larger sizes can be placed overhead easily i.e. the wire is stiff enough to support the weight of the head.

Mix brands and hence shapes – so if you have a core set of Wallnuts then next time choose Rocks or Curve nuts – this gives you different shapes and hence more options.

IGood hexcentric placementt is easy these days to grab a cam and plug it in, but wires tend to be more reliable than cams because once placed there is less risk of them walking or rotating out of position. Thus wires are great for main runners and belays plus competency in placing nuts allows you to save your cams for higher up the route - a critical skill on very long pitches.
Alongside the mainstream wires there are also micro wires and large nuts.

Large nuts usually have a hexcentric shape and are best slung on dyneema. The better models - WC Rockcentrics and DMM Torque – have complex offset shapes that allow them to cam into a crack and offer the climber large protection at a fraction of the weight and cost of cams. In many situations these units can even be stronger and more dependable than cams.

It is commonplace to dismiss ‘hexes’ as being just for beginners, but knowing how to place the hexes well is a really useful skill that allows you to maximise your options and perhaps save your cams for when you really need them.

Don’t go for hexes on wire they are far less versatile.

Micro wires come in many different forms and, once again, variety is the key. You won’t these when stating out, but any extreme leader worth the name has a decent selection of micro nuts. RP’s and DMM IMPs are the best mainstream micro wires.

Camming Devices – Active Protection

Cams have changed climbing and the routes that can be climbed because in certain placements nothing else will fit – however they are expensive and heavy – so choose your first cams carefully. The usefulness of cams also depends a lot o the type of route and rock being climbed; parallel Grit cracks and Gogarth flares can often only be protected by cams, but mountain routes are often better protected by carrying more wires and dumping some cams.

The key sizes when forming a rack are 20-30mm, 30-45mm, 45-70mm – this equates to a Wild Country/DMM 1.0, 2.0 and 3.0 or BD Camalot 0.5, 1 and 2.
Once you have these cams you can fill in the half sizes WC/DMM 1.5 and 2.5.
The choice then is to go smaller or larger and that will largely depend on where and what you climb. However, don’t be afraid to mix brands.

If you go larger then the BD 3 is a good choice, if smaller then go for a specific micro cam – until recently I would have recommended CCH Aliens, but ongoing QA problems at CCH and the introduction of the Metolius Mastercams means that the Mastercams are the new class leader. These micro cams are more flexible and work well in shallow cracks/pockets.

Slings

Climbers have generally migrated to dyneema slings for personal use and the best lengths are 60cm (4ft) and 120cm (8ft). A 240cm (16ft) sling can be useful for constructing belays.

Really skinny (8-10mm) 60cm dyneema slings can also be used as extendable quickdraws.

Keep each different length of sling a different colour to make it easier to identify them and most of all get a good system that avoids tangles.

Belay Device and Belay Carabiner

Your belay device should be safe to use with the ropes/rope diameters that you use – that is it should feed rope easily and yet be able to catch a fall easily and safely.
The belay device should be matched up with a suitable locking carabiner – belay carabiners are most commonly HMS shaped, but the new DMM Ultra O SG also makes an awesome belay carabiner that just does not cross load.
As always it's worth getting the most out of your belay device, meaning it should either be as light as possible i.e. the DMM Bugette (26g) or are as functional as possible i.e. the Petzl Reverso 3 (81g) which although more than three times the weight of the Bugette, allows the belayer far more options and can also be used for ascending the rope.

Nut Key

One per team – put it on a proper carabiner and a piece of cord.
Attaching the nut key directly to the harness with its integral wire gate or a single carabiner is a good way of embedding it in a thigh.

Prussic Loops

Although on many one-pitch climbs prusics aren't needed, it's worth just getting into the habit of always carrying them. Most climbers will carry two loops clipped to a karabiner at the rear of their harness - either two 1.3 – 1.5m lengths of 5mm cord, or one 1.5m and one 2.5m lengths.
5mm cord works well on most ropes, but some people prefer 6mm - again ensure that you know which knot to use and how many turns to apply to the ropes you are using.

There is more information on choosing climbing equipment at the main Rock Climbing Company website.



Saturday, 8 August 2009

Micro Wires - Soldered Brass Nuts v Swaged Aluminum Alloy Nuts

There was recently a discussion on UKC about small nuts. There are a few urban myths floating around about small climbing protection and this article was written to correct some of those myths.

Small soldered nuts are generally stronger than the equivalent size of swaged nut because you can get a wider diameter wire into the head of the nut, not because soldering creates a stronger join or because it removes a tight bend as the wire goes around the top of the nut (There is another apex at the carabiner loop). This advantage decreases as the head size increases.

When loaded to destruction these wires will normally break at the apex where they are being loaded i.e. at the carabiner. (Top tip: Use chunky biners with a wide rope/bar radius on crucial micro placements)

Thus use a 2.00mm wire and you can get circa 4-5kN out of a nut, but if you can use a 2.50 mm wire you can get 7 - 8kN.

This is where the IMPS/Brass Offsets/RP's win in sizes 1+ 2 - on an IMP/RP size 2 you can get a 2.00 mm wire in a miniscule head and achieve 5kn. A swaged nut of the same size (Wallnut 0) has to use 1.50 mm wire and the strength drops to 2+kN.

However jump up slightly in head size and you can get 2.00mm wire into a swaged head. The Wallnut 0.5 uses 2.00mm wire and is only very slightly wider than a IMP/RP 2 and is conservatively rated at 4kN. In a real world situation it is as/almost as strong as an IMP/RP 2

On IMPS/Brass Offsets/RP size 3 the advantage is further decreased because you can't get a 2.50 mm wire into the base of the head, but on the Wallnut 0.75 the head is now big enough to take a 2.50mm wire when swaged and also has plenty of metal to stop it pulling through placements. Thus the Wallnut 0.75 (same width as a IMP/RP 3) going forward will use 2.50mm wire and be conservatively rated 6kN - stronger than an IMP/RP 3.

There is a table of micro nut strengths/dimensions at http://www.rockclimbingcompany.co.uk/Lead_Climb_Course_Snowdonia_North_Wales.html in the Nuts and Slings section for fellow gear freaks.

It also needs to be remembered that the swaged micro nuts (i.e. DMM Micro Wallnuts) offer greater, surface contact which is an important consideration as a common mechanism for failure in real life is the nut pulling through the placement. Once again the devil is in the detail - using a harder (7075-T6) aluminium alloy nut as on the DMM Micro Wallnuts gives extra holding power compared to a softer 6000 series alloy, but is still (just about) soft enough to bite into the plavement.

This image shows what happens when the material used is too soft - the head just deforms under load and rips out. However make the material too hard and the nut won't bite into the placement and then runs the risk of being dislodged by quickdraw/rope movement.

Add to this the fact that standard steel wire as used on swaged nuts generally has a higher tensile strength than the stainless steel wire that must be used on soldered nuts.

On the other side of the coin IMPs/RPs and Brass Offsets will fit where the wider swaged alloy nuts won't go....

Each nut has its own strengths and weaknesses and the key thing is to understand them.

There is no perfect micro wire although an IMP/RP 2 comes pretty close; but a micro wire rack that includes IMP/RPs 2, 3 and 4, Brass Offsets 2, 3 and 4 plus Micro Wallnuts 0.5 and 0.75 is a really good starting point.

Sunday, 26 July 2009

Choosing Non-Locking, Snapgate Carabiners

Snapgates is a generic term for the non-locking carabiners that form the core of a climbers rack – there are loads of names for them - wire gates, non-lockers, plain gates, bent gates etc.

"Snapgates" covers all non-locking carabiners with either wire or solid gates and these gates can be either straight or bent.

Things to consider:

The most often asked question is wire gate or solid gate….after initial skepticism there is a general trend towards using wire gates; this is based on some solid reasoning together with some misconceptions. A wire gate biner potentially has some key advantages over an equivalent solid gate version, however the devil is in the detail.

The key advantage of a wire gates is that it should be lighter than an equivalent solid gates because the wire gate weighs less than a solid gate. This is a real advantage that has substantially reduced the weight of a climbers rack over the last few years.

Smaller advantages offered by wire gates include increased gate opening and (generally) less likelihood of the gates becoming iced up when winter climbing. The lighter weight of a wire gate also has the potential advantage of minimising gate flutter. Gate flutter sometimes occurs in a fall when the movement of the rope sets up harmonic vibrations in the carabiner, these can - in certain situations - cause the gate to vibrate open and closed. Carabiners are significantly weaker when the gate is in the open position and if a load (the falling climber) is applied to the biner whilst the gate is momentarily open then there is a much higher chance of the biner breaking.

However so much also depends on the design of the carabiner itself and the stiffness of the spring in the gate - I would far prefer to fall onto a well designed, ‘strong’ solid gate biner with a ‘positive’ spring tension than a poorly designed ‘weak’ wire gate with a low/inconsistent spring tension.

There is misconception that wire gates are stronger than solid gates. but in general this is not true. The only exception is in the minor axis test where the extra malleability of the steel wire gate can allow higher readings to be obtained. However this is the least important of the tests and minor axis loading should be virtually eliminated in well designed snapgates – the gate/nose interface is far more important and a far greater source of breakages.

The gate/nose interface – where the gate meets the body is the downfall of many wire gates because the design has been taken straight from its solid gate antecedents. This often means that there is a massive notch where the wire gate sits that is perfect for hanging up on wire/tapes/ropes and loading the biner away from the spine. This is made even worse if the carabiner has a long fat top bar a weak gate open strength and a weak spring. Simple stuff, but there are a lots of poorly designed biners out there - the current Clog wire gates are a good example of how not to build a carabiner.

Generally I would choose a good quality, strong, lightweight wire gate for traditional or winter climbing, but go for good quality, key lock solid gates if sports climbing.
Sports climbing is hard on biners because the steel bolts used to protect sports climbs can chew up the relatively soft aluminium used on carabiners very quickly. A chunky sports draw will last a lot longer than a minimalist wire gate, the key lock nose makes stripping routes much easier and the extra weight is offset by the fact that the draws are often left in-situ on sports routes for red-point attempts. A lot of people also feel that a well shaped bent gate carabiner is easier/faster to clip in extremis than a wire gate.

A lot of people say that carabiners should not be anodised, but there is a very strong case for anodising as long as the anodising is done in an environmentally safe manner. Most climbing carabiners are made from the 7000 series of aluminium alloys because these offer the holy grail of potential high strength and good ductility; however a downside of 7000 series alloys is that they are very susceptible to salt corrosion. Anodising really helps slow down the corrosion process and stop biners from seizing up.

Weight, shape and size are entirely personal and come down to looking/playing with the various options. The lighter modern biners are almost always smaller than their heavier counterparts and you need to choose where to draw the line on a carabiner being too small to use effectively.

Choosing snap gate carabiners – key things to look for:
  • A good gate open strength – 9kn or 10kN. 7 kN is just not enough – there is no margin for error in manufacturing tolerances and it is quite possible to generate 7kN in a fall especially when using a static belay device (GriGri) or a thick, old rope.
  • A well designed body that drives the rope into the spine i.e., no flat long top bars.
  • A minimal notch where the gate meets the nose of the carabiner to minimise the chance of items hanging up on the notch and so loading the biner away from the spine.
  • Check the spring tension – it should be firm and constant without being stiff.

Choosing snap gate carabiners – nice finishing touches:

  • A shrouded nose – helps stop the gate opening accidentally
  • Anodising – help stop the biners seizing up
  • Separate colours for either ends of the quickdraw on wire gate draws. One end of a draw should always be used for clipping gear and one end for clipping the rope – this is because the gear end often becomes marked and notched where bolts or hard materials dig into it under load. These nicks and marks can pull threads on ropes, slings and harnesses. Solid gate draws have a straight gate biner for the gear and a bent gate for the rope – no chance of mixing them up; however wire gate draws can easily be used the wrong way around unless the carabiners on the different ends are identifiably different.
  • Rope groove – helps keep the rope close to the spine.
There is more information on climbing equipment and how to use it on my main website.

Wednesday, 22 July 2009

Sea Cliff Climbing - Mousetrap at Gogarth

I did a day at Gogarth with the Hard Rock Challenge Team when they were touring the country ticking all the classic routes in Ken Wilson's seminal book.

The route for the day was Mousetrap itself and we completed it in challenging conditions between heavy showers - awesome climbing on amazing rock.

The Hard Rock Team were being photographed by a couple of professionals and I was surprised to find myself on both the front cover of the Climbers Club journal and the August edidition of climb.

Hopefully both will drive people onto Gogarth and stimulate them to explore the wonderful sea cliff climbing on this wonderful crag.

Tuesday, 21 July 2009

A Busy Year for Climbing and Scrambling Courses


This year is turning out to be the busiest ever and it is great to see the outdoor industry in general bucking the recession.

I have been instructing pretty much constantly since early April and it has been really good fun. The amazing early season weather has gone away over the last couple of weeks, but hopefully the sun will come back soon.

It has also been really nice to receive a lot of really nice 'thank you' notes including a card from a great couple whom I worked with on a scrambling course in Snowdonia.

I'm really lucky to have such a great job.

DMM Torque Nuts


The photo on the left shows a DMM Torque nut that has been tested to destruction.

The 8mm dyneema webbing has pulled through the top of the nut at over 19.5kN. The dyneema webbing is pretty much in perfect condition.

The nut is rated at 14kN.

DMM have been busy fine tuning the Torque nuts over the last month and are now getting all the sizes breaking at over 17.5kN in any orientation on any size.

This is partly due to fine tuning the heat treatment, but largely due to perfecting the sewing on the 8mm dyneema.

DMM are pretty excited by this new dyneema webbing as it has allowed them to show the first 8mm dyneema quickdraws that use constant width webbing.

The dyneema uses a tubular costruction that is incredibly durable and resists fluffing really well.

The picture on the left shows another Torque nut that was pulled in another orientation and made 22kN before collapsing.

8mm dyneema vs aluminium - no contest..

There is more information on climbing on DMM Torque nuts and hexes on my website in the Climbing tips section under the main text about the climbing courses.

Friday, 26 June 2009

DMM Dragon Cams


We have just been evaluating the new DMM dual axle cams that are about to be unveiled at the July climbing trade shows.

They are looking pretty awesome.

The cams are all hot forged and have a true three dimensional shape. This has allowed DMM to reduce weight and keep strength. The stem uses a patented system that creates a lightweight, durable and flexible stem. The cams will use the same doubled sling that has made the 4CUs so popular.

Cam angles have been kept at 13.75 degrees and the larger units are coming in 10-15% lighter than the equivilent units.

They have been named Dragon Cams.

Sunday, 21 June 2009


My mountain leaders first aid certificate is up for renewal soon so I was trawling the web for info on the 5 minute presentation that I had to give on avoiding common climbing accidents.

I came across a US site that I thought was worth sharing for several reasons. The site Traditional Mountaineering is based in Bend, Oregon and provides some really good information on mountain safety.

I have climbed a couple of times at the famed Smith Rocks which are situated just outside Bend and always considered it a 'fun' venue and it was a interesting to see the number of accidents that have happened here, especially the number of accidents caused by belayers lowering the leader off the end of the rope. The details showed that the accidents occurred to a wide spectrum of climbers - experienced and beginner - on a whole range of route grades.

This really mirrors the finding of the German DAV and Swiss Gaswerks Climbing Wall in a survey of climbing wall safety and accidents that they carried out over a 2 year period - learn to habitually belay well and always pay attention.

When we were at Smith we could virtually always see the snow topped mountains further north looking pictureque - the accident reports for these mountains shine a different light on them and the Traditional Mountaineering site provides solid information on how to prepare for trips into the mountains and a list of key items to take along so that when things go wrong you stand a better chance of staying safe.

The list of 10 essential items is great and I would certainly second the usefulness of gaffa tape in your emergency kit - awesome stuff that can patch, seal, splint and tie.

Silvi

Sunday, 7 June 2009

Chilam Balam Cave Topo and Guide


After a frantic trip to Spain to help the aptly named Rok to learn how to climb - Rok was brilliant, one of the best, most determined clients that I have had - we have finished the first part of the Villanueva del Rosario climbing guide.

There is no published information to this area and so we have built the guide from scratch with the help of the local climbers - many thanks to the two Carlitos and Manolo.

The general consensus is that for the time being the guide will not be made public in order to keep the area quiet and unspoilt.

Documenting the amazing Chilam Balam cave was awe inspiring; Chilam Balam is obviously hard, but the sheer majesty of the lines of La Rubia and La Chispa makes them so jaw-droppingly good.

Time to train harder....

Saturday, 6 June 2009

Dyneema is strong...very strong

The DMM Torque nuts are almost ready for release and have been going through the final stages of testing and certification.

I was surprised to discover that the Torque Nuts have been designed to reach their breaking strengths and then break in two different ways. The smaller nuts reach their rated strength of 14kN and then it is the dyneema webbing that breaks.

However the two largest sizes have been designed so that it is the metal chock that breaks/deforms - in this way the weight of the chock can be kept to a minimum. The 8mm dyneema webbing is actually stronger than the extruded aluminium nut!

The image to the left show a Torque nut that has been tested and was deformed by the webbing - the dyneema webbing was perfectly fine and was then seperately tested before breaking at 24kN.

In another test the dyneema actually pulled through the top holes in the nut at 17kN!

Apparently one of the key processes to getting the nut to behave in this way is machining very smooth radiuses on all the edges of the internal holes.

Saturday, 30 May 2009

Testing Old Carabiners and Slings

The Strength of Old Climbing Equipment

I am often asked about climbing equipment - what equipment people should buy, should people buy second hand equipment, does minor damage affect equipment etc. This article is taken from my website Rock Climbing Company

DMM recently received an old quickdraw from a customer who wanted to know how strong their old quickdraw would be.

The quickdraw consisted of 2 DMM Lynx carabiners - one plain gate and one bent gate that the customer said were about 20 years old plus a Petzl quickdraw sling that was also difficult to age.

The plain gate carabiner (1) generally seemed to be in reasonable condition with the key exception of the latch end of the gate. The end of the gate had suffered from salt corrosion at some point in its life and now was visibly corroded and the metal was exfoliating slightly,

The second image shows this in more detail - on the Rock Climbing Company page you can roll the mouse over the image for even more detail. This was considered serious damage as this part of the gate holds the rivet that locates into the latch in the nose and is structurally very important.

The bent gate carabiner was in quite good condition with very little visible damage and no visible corrosion.

The sling was slightly faded and had some abrasion damage at the end that held the plain gate carabiner. The fibres around the abrasion were quite fluffy, but there was no obvious cutting of the fibres. Again this is a bad place to have damage because quickdraws virtually always break at the apex where the load is applied

Initially we tensile tested the complete quickdraw using the standard carabiner test.

The first item to break was the sling (2) - this broke at the low figure of 9.23kN. It broke as expected at the apex with the abrasion damage - the 'slight fluffing' has cause a strength decrease of almost 60%.

We then pulled the individual carabiners.

The plain gate with corrosion damage (1) broke as expected at the gate as the rivet pulled free from the corroded gate. This carabiner broke at 12.55kN - when new it was rated 24kN, thus it had been substantially weakened, but was still suprisingly strong considering the extent of the corrosion.

The last carabiner was reassuringly strong and made a massive 27.90kN - cruising past its rating of 24kN more than 20 years after it was first made.

The morale is "visible damage relates to actual weakness - especially with fabric items".