Author Topic: Wanted: Practice on 20-30+m freehanging pitch  (Read 1177 times)

Online alastairgott

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Wanted: Practice on 20-30+m freehanging pitch
« on: May 19, 2019, 09:40:44 pm »

Bit of a random question, but I would like to practice on surveying a medium sized pitch (20-30+m) which I cannot touch the walls while I'm prussiking. The only complication is I want to use "modern methods" rather than the plumb bob method, so relies on the use of disto and PDA/android.


Had a few failures today, which was frustrating. So I want to iron them out before we go back.


That's why I want suggestions for pitches where you can't easily touch the wall from everyone, not just surveyors.


Don't mind where it is in the UK, I just want suggestions of a place that I can go which is good for the job of practicing.
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Offline Maj

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #1 on: May 19, 2019, 09:54:03 pm »
Star Shaft, 28m. Near Shipham, Mendip.

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Offline Duncan Price

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #2 on: May 19, 2019, 11:26:56 pm »

Bit of a random question, but I would like to practice on surveying a medium sized pitch (20-30+m) which I cannot touch the walls while I'm prussiking. The only complication is I want to use "modern methods" rather than the plumb bob method, so relies on the use of disto and PDA/android.


Had a few failures today, which was frustrating. So I want to iron them out before we go back.


That's why I want suggestions for pitches where you can't easily touch the wall from everyone, not just surveyors.


Don't mind where it is in the UK, I just want suggestions of a place that I can go which is good for the job of practicing.

The 25 m pitch in Home Close Hole.  I surveyed it several years ago.  I lowered a tape measure attached to a plastic coated diving weight.  It's a Y-hang and tight at the top but then bells out.  You are close but not touching one wall.  On the way out I stopped every 5 m and did splays as well as a shot down to the base station to define the shape of shaft*.  There's digging there in the upper series most Sunday afternoon and the team will be pleased to see you.  The pitch is currently rigged as we are working beyond S10 in Wigmore Swallet.  40 m of rope is more than enough to rig it.

* https://www.dropbox.com/s/871hz4seq936ruw/wighall2pitch.mp4?dl=0

Offline mikem

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #3 on: May 20, 2019, 06:31:58 am »
Interesting that the only pitches offered so far are on Mendip...

Offline JoW

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #4 on: May 20, 2019, 06:49:37 am »
I'm not sure on the exact pitch lengths, and I'm sure there's more, but off the top of my head:
Yordas top entrance and the descent at the end of chapterhouse
Lancaster hole
Pool sink (3rd ish pitch)
Flood entrance main pitch

Offline Alex

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #5 on: May 20, 2019, 09:22:44 am »
The Pikedaw Calamine Caverns Caverns has an ent pitch of 25m straight down the middle of the shaft. No wall touching there.
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Offline nearlywhite

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #6 on: May 20, 2019, 09:34:41 am »
Interesting that the only pitches offered so far are on Mendip...

As they have their amchairs at the ready...

Last pitch of North route Eldon?
To the rebelay in entrance shaft of rowter
2 of the pitches in maskhill
There's one most of the way up block hall.

Otherwise use a big arse pitch and just do 20-30m? Like the top end of leviathan before it bears the wall/ledge

Offline Swallowneck

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #7 on: May 20, 2019, 09:56:50 am »
Been pondering this myself, pitch surveys are never fully satisfactory with a disto and then Loch models look a bit rubbish.

I like Duncans idea and if I remember correctly from the Titan survey it looks like something similar was done there. Maybe RE could enlighten us as to how they did that.

The first entrance pitch in New Goyden has most of the problems you need, I have been meaning to go back and re-do that for a while, not 30m but very easy to get to. Come over and let's have a go.

Nick 

Offline Andyj23UK

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #8 on: May 20, 2019, 11:17:25 am »
to save you " running up and down teh country :

eldon hole ? - final pitch SW route or final pitch North route [ using the rebelay as a start point

Online droid

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #9 on: May 20, 2019, 02:13:42 pm »
Elizabeth, down Nettle
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Offline Leclused

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #10 on: May 20, 2019, 02:41:27 pm »
I presume accuracy of the compass is not that import. You only want to try-out work methods. So metal structures are perhaps an option too. So why don't you use an (abandoned) elevator shaft or an other tall (industrial) structure.
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Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #11 on: May 20, 2019, 06:38:50 pm »
I guess, it's to try and work out a process.
 At present, i'm woeful at best at surveying a pitch which is anything above 10m, (despite technical hitches which I wont go off topic to describe!)

Now I've prussiked up the pitch and therefore seen it for a second time (it's not a new pitch, so don't get excited!). I can see that I will struggle but will persevere.

I think what I may end up doing is surveying down the pitch, as there is a slope off the bottom which I think may make it easier than missing the top of the pitch and hitting the roof.
 Also this will ensure I can get a tidy picture of the pitchhead.

What I'm thinking is two separate series' of shots:
1) a straight "plumb bob" type shot straight down the pitch to give the model a fair idea of the size
2) a series of shots connecting the start and end of the plumb bob using forward shots, back shots and continue here usage to get the splays of the pitch. This may work "ok" on the pitch I have in mind (3-5m from the wall), but would almost certainly not work for other larger pitches.

Process of thought for series of shots (2)

a) So I guess what I'm thinking is stand at the top of the pitch and pick my next point on the wall further down.
b) shoot a leg to that point on the wall
c) abseil level with that point, take a back shot so that i'm a survey station on the rope
d) immediately take the next shot to a point on the wall.
e) return the software to my point on the rope and continue to take measurements of the walls around me (splays).
f) abseil down level or below the point on the wall.




Having said that I really do like Duncan's technique.


I might have to try out both and see which I like/which is less faffy when your sopping wet. (most probably Duncan's now I think of it).
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Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #12 on: May 20, 2019, 06:43:19 pm »
Thanks for all the suggestions, I've got plenty to practice on, I was also sent Sell Gill final pitch by an anonymous forum lurker  :beer2:
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Offline damian

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #13 on: May 21, 2019, 06:18:15 am »
Thanks for all the suggestions, I've got plenty to practice on, I was also sent Sell Gill final pitch by an anonymous forum lurker  :beer2:
Middle pitch, surely?

Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #14 on: May 21, 2019, 07:24:23 am »
No idea i'm afraid, probably the pitch I once handed my handjammer to a person using ladder and lifeline so they could haul another group of unsuspecting "cave hunters" in trainers out.

i'll find it!
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Offline mikem

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #15 on: May 21, 2019, 07:59:40 am »
Middle pitch, surely?
Unless that's as far as they got...

Offline Rob

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #16 on: May 21, 2019, 11:25:50 am »
I also suggest Elizabeth in Nettle (mainly because there's currently quite a large error in the Crumble-Elizabeth round trip and i'm pretty sure it originates from Elizabeth  :thumbsup: ).

I don't understand why surveying a 20-30m pitch is hard with a DistoX. It's just another leg.

If you really want to split it up a bit (say, to add splay detail which can't be accessed from the top of bottom) then just make yourself a "floating" point in the middle.

...I like Duncans idea and if I remember correctly from the Titan survey it looks like something similar was done there. Maybe RE could enlighten us as to how they did that....
Yes, Moose populated Titan with horizontal splays every 5m along a hanging tape.
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Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #17 on: May 21, 2019, 12:40:27 pm »
I guess it’s not, I’ve just had no practice. So before I go back I just need ideas to practice.


Otherwise I’ll be THE definition of insanity ;D [size=78%]: trying the same thing expecting a different result! [/size] :o
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Online RichardB1983

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #18 on: May 21, 2019, 01:05:44 pm »
Frank Shaft in West Mine is pretty much bob-on 20 metres if you are at Alderley tonight, and can be set up to be free-hanging without touching the sides I think. It's got an optional bar about 2/3 of the way up for a re-belay if you want to make the surveying more interesting.

At the end of the entrance passage, turn right after the short ladder. Then go past the top of the next ladder into the low passage beyond. There's a bar across the passage just before the shaft top (which is just a hole in the floor).

The bottom part of the shaft just opens up into a medium sized chamber (a continuation of the main chamber) so you could do some splays to get the shape

Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #19 on: May 21, 2019, 02:27:48 pm »
Afraid not, seeing family tonight.

Perhaps next week. Thanks again for borrowing your batteries!
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Offline Tseralo

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #20 on: June 02, 2019, 04:12:47 pm »
What if we took a plumb with 5m increments marked on it.

  • Hang the plumb from the rebelay.
  • Shoot to the start of the plumb
  • Shoot down from the start of the plumb to the end.
  • Abseil down take splays out then shots up and down at each 5m increment


Online alastairgott

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Re: Wanted: Practice on 20-30+m freehanging pitch
« Reply #21 on: June 02, 2019, 04:59:44 pm »
I think I prefer the idea of targets at the top/bottom of the pitch which are tied into the survey then just take back shots to those targets from any point on the rope and splays from those points. As per Duncan's suggestion.
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