Frangible pins thoughts... Burghley in particular...

[Foxfolly]

I saw a number of these on fences at burghley.

But watching the highlights on sun saw a horse crumple onto a fence at the waterloo rails and the pin didn't break, fortunately the horse didn't go over the fence and slipped back down it but the angle at which he crumpled I was very surpised that it didn't go!

Now to me they seeem to be positioned in the face of a fence with an upright behind the rail that is on the frangible pin.

Surely this means that if the horse hits the fence quite straight on the impact will not be downwards and therefore not break the pin. ... If the impact is straight when the horse has taken off and is in the air, then this is the type that can become a rotational....

This made me think about the falls I saw at the first mushroom which were mostly a rotational type falls caused by legs left on the fence at varying degrees of severity and although I know you couldn't use a pin on that type of fence IMO if they had been a frangible type fence I think the pin probably wouldn't have broken on those either due to the angle of impact!

Which also made me think about the fatal fall at Hartpury where the pin didn't break and the people who described the fall stated that the horse didn't hit the fence particularly hard!

My thoughts are that surely on a frangible pin it would be more effective if the supported rail didn't have an upright rail behind it? But then maybe there is a reason for this ie. it is because they would break too frequently??

Not sure I've explained it very well but what does everyone else think? Or does anyone know the official science behind it?

 

[Firewell]

sounds like you could be right.

I have this wild idea that accidents happen because fences are so more technical these days. Accidents dont happen as much team chasing or XC in the olden days, because I think fences were big (horredously scary to me!), more straightforward and required a bold galloping horse. It all used to be about huge drops, huge ditches and massive hedges, fences that require forward riding and forward thinking.

Nowadays its all about technicality and skinnys, fences that require a horse and ride IMO to back off a bit and the rider to showjump but intspersed with big 'flying fences' , which I think must interrupt the rythm?? Doing lots of skinnys, turning and jumping out of a canter to be accurate and then kicking onto a flying gallop for the next fence, it just doesnt sit right with me.

But then what do I know?? Im not keen on riding XC because its too risky now.

 

[Bossanova]

Frangible pins are the best that they could come up with for the knowledge we have about rotational falls at the moment. There's a huge study going on this year which may throw up new options.
They're designed to only break on tru rotational falls as they can actually be more dangerous if they break when it isnt a true rotational falls.
None of the falls I saw at Burghley were rotational.
If those rails had collapsed then that horse may have crumpled flat onto his face, possibly it was therefore better that they didnt.

 

[kerilli]

i think that the upright behind the rail is to stop the rail being carried forward with the horse. i've seen some terrible falls sj when a horse has tipped out a pole with its front legs and got it between its legs. the thought of this happening with a xc pole is terrible - it would break legs and possibly necks.
the pole is designed to drop downwards if enough downwards pressure is exerted on the pin, that's my understanding. this should be enough to lower the fulcrum point and prevent a rotational. usually.
the Hartpury fall - i read that the horse hit the fence with a fetlock, no higher. not sure if this is true. not sure how that could lead to a horse fall tbh, rotational or otherwise - usually the fulcrum point needs to be knees or above for a horse to fall.

i don't think the courses are really that much more technical these days, with the exception of skinnies, which horses and riders are very experienced about now, and angles, which are much more demanding than they were. it's swings and roundabouts.
for instance - think of jumps into water at 4* level in the past. that infamous bounce of white rails at Badminton. various other bounces, combinations, and what about the big drop over wall at Burghley, or the bounce up step into house one stride out over big solid upright wall with drop down into water again (at Burghley Euros). etc etc etc.
what did we have on Saturday at Burghley, by comparison? jump into first water which everyone took was a single soft brush (good job, or Comanche for one would have turned over at it) which, on its own, i think wouldn't have looked horribly out of place on most Intermediate courses. the horses could brush through the top 6" at least.
the alternative route (which no-one went near) was much more difficult, the ground ran down and drew the horse into the bottom of the fence, it had no groundline other than the edge of the water (or a raised, false groundline of the bottom of the brush, suspended about a foot above the water). not surprised everyone left that one well alone! the other route was probably the kindest fence into water i have ever seen at a 4*.

i think the best combinations don't have to come back to a canter to be accurate at the skinnies, they have enough trust and accuracy to keep coming at a good pace.

sorry, i've gone on and on!

 

[SteveGG]

In my opinion the frangible pins were designed to deal with the true rotational fall where the horse hits the fence at some point above the knee, or more likely at chest height. The momentum of the horse results in the whole horse rotating about the point of contact. The weight of the horse then causes the pin to break and stops the rotation.
The pin will only break if there is sufficient downforce.
The horse at the waterloo rails simply slammed into the fence and the weight was fairly evenly distributed, at no point was the horses weight taken completely by the top rail.
Frangible pins were designed to cope with one particular type of fall and I remember seing one particular fall where it work very effectively. As Boss said they are working hard to get additional data to improve the situation.

 

[kerilli]

yes, agreed. the horse who stopped at the Waterloo rails only had the weight of his legs against the fence, i think... he was stopping, not rotating over the fence. there was no downforce at all, i reckon, as he had most of his weight in his hindquarters as his head came up and he almost sat down to stop.
this is obviously completely different to a horse falling forwards over the fence, using the top of it as a fucrum - this is what frangible pins are supposed to prevent, because they effectively lower that fulcrum point which means that the horse is less likely to continue its flip-over trajectory.

 

[MissDeMeena]

Kirilli, it's what i've been going on about for ages.. everyone thinks that courses have become more tech. now adays, when they haven't at all!! infact, they've probably become kinder!!

I wont comment on the mushrooms at Burghley, as i don't know enough about them, and i only saw 2 falls there..

My theory for so many dreadfull XC falls is the same as Jim Woffords, that everyones obsession with dressage is what's doing it!!!!! It's taking away the horses ability and desire to think for itself!!

Even the poster above who said they think course have become too tech. kinda refered to it.. in saying that you don't see these kind of falls team chasing or p2p'ing... answer, team chasers and p2p'ers don't do endless dressage schooling!!!

Obviously there will always be the exception to the rule, like our dear Connie (forum horsey

) who to put it kindly isn't the best dressage horse, but was VERY unlucky to have that fall at Burghley!! However, take the way she jumped round the rest of the course!! Awesome!!!!!

 

[Foxfolly]

[ QUOTE ]
i think that the upright behind the rail is to stop the rail being carried forward with the horse. i've seen some terrible falls sj when a horse has tipped out a pole with its front legs and got it between its legs. the thought of this happening with a xc pole is terrible - it would break legs and possibly necks.
the pole is designed to drop downwards if enough downwards pressure is exerted on the pin, that's my understanding. this should be enough to lower the fulcrum point and prevent a rotational. usually.

[/ QUOTE ]

I understand what you are saying, but the retaining rope on the rail surely would prevent this scenario?

I can see how breaking too early could actually make the fall worse with a horse who would have braced on the solid fence and stayed on the ground actually landing on their noses, with the horse I was referring too that may well have been the case.

Not sure if having the lower rails fixed would stop that happening or make it worse. I think on the waterloo rails all the rails were frangible but most of the ones I have seen its usually only the top rail.

Out of interest the type of fall at the mushroom I thought was a rotational type fall, although none were a full rotational fall.
Am I incorrect in calling them that?

My opinion of the fence was that horses were misjudging the fence and not getting high enough over it. But I'm not convinced it is the type of fence just maybe the location with the drop on the landning or maybe the fact that they were coming out from a heavily wooded, and therfore dark area into a lighter clearing.
I have jumped that type of fence a few times and not had problems, obviously not at 4* though

1 was like a big egg out in the open (Allerton Park PN) and the other was a mushroom in woods (Northallerton N).

I have a picture showing Laura's horse just prior to take off and you can see she is just too close to get over cleanly. But it has to be said to me her aproach was perfect, some came in way too quick not giving the horses a chance to see what was expected! I also have a pic of (I think) the next rider who's horse jumped cleanly but it looks like the stud girth is touching the top of the mushroom where it is so low over the fence! I'll try to put them on here later!

Also what do pleople think would prevent that type of fall happening as I think it was only by luck that none of the fallers were injured more seriously. The photos of Laura look pretty horrendous!!

 

[TableDancer]

Perhaps there should be some design whereby the upright behind the rail is, in some way, frangible so if the whole weight of the horse is on it it will break - in that situation surely better for pole to travel (despite associated risks) than horse to somersault