/ the right unconquerable rock fall!
Flake + cams = bad
Is this a new section breaking off, or the bit that broke off about 10 years ago?
rock at the bottom that is proof enough and a hole where it used to be. happened on saturday. Im surprised that im the first to tell people on here.
(Im sure it did i just was in school in devon)
So where has this bit of rock come off then? The piece by this guy's knees has been gone for at least 15 years.
In the picture provided by monk above, would that flake not be safe to put a cam behind? It looks pretty substantial from this angle. Like it goes back quite deep into the rock at a steep angle.
Just wondering. Sorry for thread hijack.
That's the whole point of the thread - cams have exploded two large chunks off this wonderful flake. So not entirely safe, no, although the flake must hold many, many falls, plenty of them onto cams, each year.
It's a real shame, a beautiful line which is starting to look literally dog-eared.
Pretty sure I got good wires and hex's the whole way up this when I lead it, not sure i even placed 1 cam. I don't think i even had any cams when i climbed it, most Hvs's can be reasonably well protected, probably better so, with a good set of wires and a few hex's.
As legend would have it the lower chunk was the victim of a vicious car-jacking surely?
My understanding is that the first damge was'nt caused by a cam, but by some idiot using a carjack to retreive a cam?
I thought the lower one was caused by a jack when someone tried to retrieve a stuck friend?
I think this is an urban myth.
Crikey. Never seen a triple whammy like that before. I thought the carjack thing was an urban myth, too, but happy for the 'jacker' to confess all!
I probably overstated it - I guess the most we can say is that on current evidence, we should be regarding that flake with a bit of suspicion when sticking a cam behind it, particularly as there are some nice hex placements etc.
Surely its a rural myth rather than urban.
> Surely its a rural myth rather than urban.
Have you been to Stanage recently? I felt less hemmed in by folk walking across the concourse at Victoria.
It's the melting pot of modern mountaineering - people from every university in the land.
It may be a myth though it was pretty widely reported at the time (I would guess more like 20 years ago). The tip of the flake is/was supposed to reside on a mantelpiece somewhere in the North of England, though as I don't think anyone ever owned up that may also be a myth.
I heard that the whole route was created by Whillans tearing the cliff assunder.
The top of the jug at the crux of Indecent Exposure used to reside on my mantlepiece in Sheffield. Well, you didn't need it anyway!
I offered to glue it back on, if required, but there were no takers. Must have ended up in the bin when I moved.
> The top of the jug at the crux of Indecent Exposure used to reside on my mantlepiece in Sheffield. Well, you didn't need it anyway!
> I offered to glue it back on, if required, but there were no takers. Must have ended up in the bin when I moved.
Good job you were'nt a Swanage habituee, if you were into gluing holds back on
Quote from a Swanage pioneer, "The flake on Gypsy's fallen down. It's even safer now..."
I understand that the piece that came off has been kept for prosperity and resides in Sheffield.
Clearly you've never been to victoria station
That's the funniest but in stone monkey!!
> I heard that the whole route was created by Whillans tearing the cliff assunder.
It's not often I laugh out loud, but this made it happen.
Thought he lived in Wales.
Judging by the accent of the bloke who took the fall it won't be residing in sheffield. Newcastle is probably closer the mark.
No. It's in Sheffield, trust me.
I think that the whole cams behind flakes ia load of sh*te, especially for the RU.
Think about this for a minute....
I have quoted sizes to make it easier to understand, rather than any other reason.
a 30-40mm wide placement
Use a cam that has a 32mm max size, load it in a fall, how much will it expand? Very little, only the bite into the rock surface.
Use a nut that has a 32mm max size, load it in a fall, what happens, it wedges tighter into the crack.
Now use a cam, that is say 42mm at maximum expansion, if it is in the same placement, how much will it expand? Once again, only into the surface of the rock.
The loading placed upon the gear, does not increase just because it is a cam.
A cam will force into the placement, and then relax, as it becomes unloaded.
A nut will wedge into the crack, and exert the force on the placement until it is removed.
In the case of a loose flake, then cams may be a problem.
a 32mm nut or cam, will wedge the flake open, until 32mm, and then either hold or fail.
a 44m cam will do the same, but just force the placement wider.
Any gear placed behind a loose flake will lever it off, cam or nut.
In the case of the RU, this flake is not being forced to any noticable amount.
However, shock loading of a piece of gear, may cause the bond between the grains of grit to fail.
The force exerted upon the placement is the same, there is no mechanical advantage being gained by a cam, to turn a fall of 3kn in 6kn.
The problem with cams is, the walking action, that erodes the surface of the rock. I noticed this a Brimham recently, where a horizontal break, proably took a 2 1/2, and will now take a 3, just by the rock being worn away, by cams walking.
I hope that makes sense, and will happily be proved wrong, by a reasoned and sensible argument.
I think the car jacking was late 70s..
> Clearly you've never been to victoria station
Used to fight my way across it (in the wrong direction) every morning. Slight hyperbole, but it is to other stations what Stanage is to most other crags.
Both outward, maybe slightly more vertical in the case of cams, but the loading force remains the same, both would be shock loaded in a fall.
Friable flakes are the problem, and you are aware of those when you place the gear, and yes, in those instances a larger cam than required, may cause more damage.
It is the sweeping generalisation, rather than the specifics, that I feel is misleading.
But as I said, a nut will also have the same wedging effect, a cam does not impose more load just because it expands. What does a nut do, as it is forced into a constriction? In effect it is expanding outwards to fill all available space (ok a nut doesnt expand, but I hope you get the idea)
I'm buying very little of this.
Cams work by mutliplying the force being pulled down on them on to the walls of the crack this in turn increases friction allowing them to hold falls. I believe it's roughly double the downward force on each edge of the crack. (www.vainokodas.com/climbing/cams.html)
I'd have to do the math on nuts to work out the force against the side walls, but I think the math is much more complicated with a nut as small grains of rock between the nut and the rock and irregularies in the rock and friction as the nut seats better will have a large part to play in exactly how much force is exercted outwards on the crack. Remember for the nut to get more wedged it needs to move against friction which is going to increase the more wedged in to the crack it gets. Personally I'm going with climbing folk lore on this that cams exert more force than nuts when behind flakes etc.
"Both outward, maybe slightly more vertical in the case of cams, but the loading force remains the same, both would be shock loaded in a fall."
the force on the quickdraw attaching to the gear would be the same yes. It's highly unlikely that the force exerted on the rock would be the same. If you are sure it is I'll ask you to do the math and prove it.
The fact is that a cam will continue to expand, forcing the flake out until it reaches full extension. This I am sure you will agree is generally much wider that the case for the nut.
This extra distance may well be enough to cause the failure of the flake...
That was the point I was making.
Using a larger cam than required on a friable flake will force it out.
On none friable flakes, of which the RU is one, using a 2 or 21/2 in a placement will not change the force upon the rock, and will not force the flake apart any more with the larger size.
If you body load a cam in a crack, at 75kg, then put a larger cam in, the body load is still 75kg. The larger cam will not force, what is in effect, 2 fixed sides out further.
> The loading placed upon the gear, does not increase just because it is a cam.
Unfortunatly that is wrong. The forces placed by a cam on the rock are much much higher than those caused by a nut.
A nut and a cam are loaded by a force X this causes a force R to be exerted by the gear on the rope and a force F by the nut on the rock. In a nut placement this force is caused by the nut trying to move through the rock and thus the force of the nut on the rock is about the same as the force of the rope on the nut so X=R~=F.
For a cam the force R caused by the cam on the rope is the frictional force caused by trying to pull the cam out of the crack (this force is the same as in the nut placement). To generate this force the cam puts a force on the rock perpendicular to the direction of the pull this force is the frictional force divided by the co-efficent of friction and is thus several times as much as the force on the cam so X=R < F
A nut that is held in place by friction will fail in a fall. The reaction force on a nut is provided by trying to pull the nut through the rock in just the same way that a table resists the force of your dinner plate.
The large pieces of flake that are now missing tend to suggest that assertion may not be entirely correct?
With a 13 odd degree cam angle, the resolved forces in the outward direction would have to be substantially higher than double - closer to 4x. This force is exerted irrespective of any movement or coefficient of friction.
A nut, on the other hand would exert hardly any outward force if the friction was high.
Indeed sir, your honour is rebound!
I have...and I think you're wrong.
I don't really get your point about a just-big-enough cam (32mm in a 30mm placement) rather than a mid-range placement. Tipped-out placements are dangerous because cams can move, not because the flake is flexible. If the flake is expanding, all bets are off anyway! Flakes on grit tend to be rigid but brittle - they snap iff suffiecient outward force is applied.
Cams create significantly (a multiple) of outward force of passive nuts. The outward (normal) force is the applied downward force divided by the tan of the camming angle. So for a Friend (camming angle 13.75 o), the multiplier is 4 x. The downward force will be affected by the length of rope out and fall distance (fall factor) as well as the type of rope. But the minimum outward force will be fourfold the climber's weight. (In fact it might be eightfold as they are being belayed from below?). If you weigh 75kg, that's 300kg (or 600 possibly). Do this repeatedly and eventually small lines of weakness in the rock will split.
Cams by design multiply the applied force and re-direct it outward into the walls of the crack almost normal to the applied load.
Nuts (unless placed in hard, slick taper) don't or do so to a much much lower degree.
The actual force generated is determined by the 1/coefficent of friction. The maximum force that can be generated is determined by the cammming angle if the tangent of the camming angle is higher than the coefficent of friction the cam will slip before the reaction force is high enough.
Assuming the friction is high enough for the cam not to slip, though, calculating the outward force is relatively simple and its a straight multiplier on the downward force excerted by the climber.
That would be anything but like its original form. But I guess you already knew that.
David, the force keeping the cam in place is the friction as you state, but the friction force (F) is the normal force (N) times the coefficient of friction (mu).
F = mu * N
now, N is perpendicular to the rock, F is parallel to it. N is constant for a given cam design and a shock load irrespective of the type of rock or its coefficient of friction. The holding force itself is not pulling the flake wide, but the normal force is.
Or perhaps classic routes shown to be vulnerable to such damage should be advised in the future as solo or toprope only... with lead ascents being 'frowned upon'?
"With a 13 odd degree cam angle, the resolved forces in the outward direction would have to be substantially higher than double - closer to 4x. This force is exerted irrespective of any movement or coefficient of friction.
Nope suggest you read this just checked the math and it looks right, the outward force on each wall is roughly double the downward force.
I've just spotted my deliberate mistake ! I forgot that the downward force needs to be resolved on both sides. I take it back; ~2x is right.
The car jack event - if indeed it ever happened - was a few years after I started climbing; so mid 80's
I say resin in a couple of chockstones, then you can thread them in an old skool J.Brown stylee and keep the feeling real man...
> I say resin in a couple of chockstones, then you can thread them in an old skool J.Brown stylee and keep the feeling real man...
Rather than gluing the chock stones in couldn't you just leave a basket of suitably sized ones at the bottom of the route so you can place your own? This would also open up the possibility for the hilarious stitch up your second antics of threading the rope behind the chock stone leaving them stuck as they ponder how to remove it :)
Move it to the plantation bouldering section under 'high balls'. :)
(I don't care, I've already done it)
But the chockstone police would remove them (Simon??)
Seriously, it was simply so that his mates could try to follow him.
It is really simple, a cam with a 13.75 degree camming angle and a wedge with a 13.75 degree taper will exert EXACTLY the same outward forces when loaded. The fact that wedges create massive outward forces is obvious to anyone who has ever used a log splitter. The same applies to hexes placed so they 'cam', they again exert large outward forces,
The only real differences between gear are first the width of the 'wedge' (surface area in contact with the rock) and second the effective length of the 'wedge' (basically how much expansion needs to happen before the gear pulls through). With the exception of micro-wires, nuts and cams have similar contact areas. However, nuts or hex placements will generally need less movement before they fail compared with cams placed at the smaller end of their range.
In 'loose' flakes this means nuts may pull through but leave the flake intact whereas with cams you may end up with both the cam and the whole flake coming away. In these cases, using nuts might be less risky.
However, as has been pointed out, in firmly attached but 'brittle' flakes, there won't be much difference between over-cammed or under-cammed cams, cammed hexes or nuts. The placement will generally either hold or fail catastrophically. In this case the location of the gear (i.e. as close to the base of the flake as possible) is far more important than exactly what gear is used.
Not quite as simple as all that, I think. You'd be right only if there were (almost) no friction between the sides and the wedge and the rock.
The same conditions under which it would be equally easy to push a sledge and a cart with wheels on greased axles - a cam has, in effect, wheels.
You can also consider the vector of the forces applied by the gear. In the case of passive pro the vector is close to parallel to the rock and therefore causes less expansion of the crack it is sitting in. For cams the angle of the vector depends on the quality of placement.
If overcammed the vector will be closer to parrallel to the crack walls. This makes it less likely to hold a fall as it cannot generate enough friction to hold itself in the crack.
If undercammed the vector will be closer to perpendicular to the crack wall. This means that it will be exerting a greater expansional force on the crack and therefore will be more likely to tear off friable flacks.
Another idea about how to protect RU; seeing as cams apply forces in proportion to the load placed on them how about proposing a weight limit - only people under 10 stone can place them!
i would presume this is the same if you are constantly falling onto a nut, of which i`m sure happens regularly on RU, where as a friend is only exerting force when fallen onto, then released when force is taken away!
all this said, i can`t see anything changing as far as RU, is concerned, unless maybe........climb per view!!
I think you are 100% wrong here. You need to draw the force diagram in both cases.
Of course a wedge works in wood - a) the friction between wood and smooth steel is low and b) you hit it with a bloody big hammer !
> Not quite as simple as all that, I think. You'd be right only if there were (almost) no friction between the sides and the wedge and the rock.
> The same conditions under which it would be equally easy to push a sledge and a cart with wheels on greased axles - a cam has, in effect, wheels.
You're correct. I wrongly assumed that friction was rather insignificant. Had a proper think about it and friction will reduce the outward forces a wedge exerts by a fair amount. If my maths is correct a friction co-efficient of 0.15 would reduce the reaction force for a 13.75 degree wedge compared to a cam from 4.09 to 2.53 times the input force.
So I suppose it is a case that whilst wedges will still exert large outward forces, cams do exert even larger ones.
Your point about different surfaces (wood/steel vs gritstone/alloy) is well made.
Thinking about it now, all the times I've had issues with nuts potentially splitting apart flakes have been on slate where there is hardly any friction. In that case the forces will be much higher and closer to that exerted by cams, but I can now see that won't be true for gritstone and other rocks.
Top tip for scientists... in cases like bumblebees fly, chalk works and cams are worse than nuts on flakes, the empirical evidence usually has some basis ;-)
Bumblebees can't fly and anyone who tells you otherwise should be stoned to death with physics textbooks.
> Bumblebees can't fly and anyone who tells you otherwise should be stoned to death with physics textbooks.
And you should really be stoned with the Oxford English Dictionary: Fly: 'move through the air under control, esp. with wings; travel through the air or through space'.
And guess what? A fly flies too.
Either I'm missing your point or you are unaware that bumblebees can't fly because it's been proven to be impossible by really clever scientists using mathematics.
Although equally clever scientists are now trying to get the bumblebee airborne again by using even cleverer mathematics.
When the bumble bees realise they can't fly they will hit the flat earth.
Sorry must remember that sarcasm doesn't translate well to forum communication, next time I'll stick in a semi-ironic smiley face. I was poking fun at the obviously stupid assertion that they can't fly.
I think that too was ironic.
Was the upshot of all this debate that the broken bit on RC was
done with a car jack ages ago (to free a friend?)?
Well I got it straight away
But can you now get serious and tells what forces come into play on doing a belly flop at the top of RU?
Sorry "tell us"
While I am something of a belly flop and whale expert I haven't yet experienced the RU whale so can't comment.
> Sorry must remember that sarcasm doesn't translate well to forum communication, next time I'll stick in a semi-ironic smiley face. I was poking fun at the obviously stupid assertion that they can't fly.
Yup. The trouble with irony like that is that it is exactly the way many serious scientists speak - indeed the way some scientifically minded people speak on these forums. The very article you quote ends with the extraordinary comment: 'The existing theory is either insufficient, or suggests complex dynamics which has not been verified and would require very intelligent design if actually true.' Why on earth this requirement for 'intelligent design' has to be dragged into it, I just don't know - because if we treat this as a riddle then it leaves much/most of the natural world as baffling in its apparent 'intelligence' as it was to the Rev. William Paley.
So it wasn't entirely clear which angle you were coming from.
> But can you now get serious and tells what forces come into play on doing a belly flop at the top of RU?
Actually, I was surprised how unthrutchy the final mantelshelf of RU was. Probably because I was so scared of it in advance I just did one very powerful/positive mantelshelf move, having got my feet up very high, and was astounded to find that when I belly-flopped forward I could get my right hand right back over the back of the block, i.e. reach a mega-jug. But it all depended on quite good footwork.
> Judging by the accent of the bloke who took the fall it won't be residing in sheffield. Newcastle is probably closer the mark.
i belive it was a scouse pirate
Just to clear something up, the bottom corner flake from Right Unconquerable resides in Sheffield in my garden. I found it obviously quite soon after it broke off but didn't see it happen. Soon after,I heard the tale of the car jack but can't comfirm that, although with cams at about £15 - £20 in those days it wouldn't surprise me.
Nice to put that one to bed then.
I have the Medusa tree stump in my garden - maybe we should start a museum!
So are we decided then?
In a deep placement in a solid thick flake, then cams or nuts will make no discernible difference.
Cams on the edge of any flake are bad news.
Chip of a few edges of the flake, and glue them inside, for threading.
Will this make any differnce to my trip to do the LU this week?
> Will this make any differnce to my trip to do the LU this week?
Only if your routefinding skills are suspect.
What sensible options can we take to preserve this route? Is the lump of rock still at the bottom or is it now on a mantle piece somewhere?
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