Otter Hole - Beyond the Upstream Sumps

mrodoc

Well-known member
Takes me back to early March 46 years ago when I had the privilege of joining a group of RFDCC cavers who were still exploring the extension they had found. I commented in my log that it must be the best decorated piece of passage in Great Britain. Rollo Gillespie forced a squeeze at the entrance to the new section and found what I think is Crystal Ball or Pom Pom passage - I couldn't get in and have never visited it. I am surprised in the intervening years that the link to the streamway beyond the sumps hasn't been made as I clearly recall one could hear the stream below somewhere near the Camp. A lot of small formations got damaged in the early years.  I remember going in to photograph 'The Saw' somewhere near Long Straw Chamber - a straw had fallen at the side of the passage and a curtain had formed along it. Somebody had carelessly clocked it with their boot and it was in fragments. I think the Volcanoes have disappeared too.  However it is still a marvellous cave and there is  considerable potential in the streamway.
 

Leclused

Active member
Otter Hole - 26th March 2022

Nearly 6 months to the day since our last trip, the weather was looking good to get back in and collect the dye detectors we'd placed. Ideally these would have come out sooner, but some inconsiderate b@stard decided to fall down OFD taking out an opportune period of time for some of us and the next season for himself! Despite this, George did kindly fill up a cylinder for me the night before, which is now stashed up at Sump 2 for a push later in the summer.

What kind of detectors are you using? And did you know that for research like yours you can rent at a low cost a device named Stream via traqua (a spin-off of the university of Namur - Belgium). The device was initially developped by a belgian caver and was then commercialised by traqua.

More in the following thread https://ukcaving.com/board/index.php?threads/dye-tracing-equipement-le-fluorim-tre-stream.28667/
 

PeteHall

Moderator
What kind of detectors are you using?
I'm just the monkey placing/ collecting the things, so I can't tell you much, but I think they are simply activated charcoal bundled up in some ladies tights. The test involved different colours of dye poured into 3 different sinks that are thought to feed the cave.

And did you know that for research like yours you can rent at a low cost a device named Stream via traqua (a spin-off of the university of Namur - Belgium). The device was initially developped by a belgian caver and was then commercialised by traqua.

More in the following thread https://ukcaving.com/board/index.php?threads/dye-tracing-equipement-le-fluorim-tre-stream.28667/
I sent a link to this thread to the chap who's doing the testing, when it was first posted, but that was after we'd placed the detectors. It's just taken a while to get back in to collect them!
 

Leclused

Active member
I'm just the monkey placing/ collecting the things, so I can't tell you much, but I think they are simply activated charcoal bundled up in some ladies tights. The test involved different colours of dye poured into 3 different sinks that are thought to feed the cave.


I sent a link to this thread to the chap who's doing the testing, when it was first posted, but that was after we'd placed the detectors. It's just taken a while to get back in to collect them!

Charcoal in ladies tights is old school but works of course. But it's a one time registration.

With a stream device you have a real monitoring with sampeling within a timeframe. So it gives much more information in time. For more scientific studies the device is the way to go.
 

TRAQUA

New member
Charcoal in ladies tights is old school but works of course. But it's a one time registration.

With a stream device you have a real monitoring with sampeling within a timeframe. So it gives much more information in time. For more scientific studies the device is the way to go.
Thank you for mentioning us :)! Good news, we currently have a project call specifically for speleology associations to use our instruments for research projects at minimal costs (only admin/setup fee + shipping costs). More info here: https://www.linkedin.com/feed/update/urn:li:activity:6917037637899845633. And to celebrate our 1-year anniversary the normal rental prices are also reduced during the months of May and June 2022. Do not hesitate to contact us ;)
 

PeteHall

Moderator
Otter Hole:
29th August 2022
Weeks of dry weather in hand, we made a plan for a push on Sump 8, having previously got as far as Sump 7.

Details were agreed, kit was prepared and a team of nine formed for an early (4:30am) start to catch the tide.

Unfortunately five of the team dropped out (or just didn't turn up) and of the remaining four, one (who had stayed overnight in the car park) wasn't on top form, having had a bit of a heavy night with some of the camper-vanners parked up there...

Still, we managed to get a pair of 7 litre cylinders as far as the first recue dump, just beyond the tidal sump, before reluctantly deciding to turn the trip and before anything else went wrong.

P. Hall, A. Torbet, A. Thompson, J. Paddley

31st August 2022
Following Monday's disappointment, I spoke to my boss on Tuesday, it went something like this "I know I'm supposed to give you two days notice to book leave, but I need to go caving tomorrow, so I'm taking the afternoon off".

Having planned for a fairly brutal solo trip, I was extremely pleased when Jann offered to help. Without kit to carry, we stormed through the entrance series and had to wait half an hour for the tidal sump to open. Even after picking up the cylinders from where they had been left, we made pretty rapid progress up to Sump 2, before heading back out, again bag-free, making surface only 2 hours 40 after entering the cave.

P. Hall, J. Padley


4th September 2022
With cylinders already at Sump 2, Andy and I opted for a lightweight, faff-free trip for Sunday. The weather was still holding, but with thunderstorms on the forecast for the afternoon; this was likely to be our last chance for the season.

Tides were kinder and we entered the cave at 9am, carrying one bag each.

Clean, keen and ready to go
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Steady progress was made to Sump 2, where we kitted up and dived up to Sump 4. I went first and had excellent visibility, coming face to face with a green eel shortly before surfacing in Sump 3. Andy had less visibility and also had a little more fun at the squeeze in Sump 4, as he was wearing larger cylinders for the push on Sump 8.

Andy surfaces from Sump 4

Splitting the kit between us, we progressed carefully up to Sump 5, where fins and line reels were stashed from the last trip.

Andy dived first, to make the most of the viz, as he'd not seen the sumps before; I followed in fairly murky water, but still got a better view of Sump 6 than I had previously seen. Surfacing, I dropped my diving kit and made my way upstream with a mini crowbar and camera; I'd previously spotted an inlet that appeared open beyond a silt bank and was going to take a look at this while Andy dived Sump 7 to look for the as-yet undiscovered Sump 8.

The Route to Sump 7
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Looking into the inlet before digging
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The silt bank turned out to be littered with fractured bits of rock, so I was very pleased to have a bar with me, I just cursed my weight saving, having only brought a 6" bar!

After half an hour, I'd just about enlarged a body sized hole through the first restriction, when I heard the sound of Andy returning, who described his dive as a having had "ups and downs". He'd reached the air bell, marking the end of Sump 7 and the end of the known cave, however despite multiple attempts he had not been able to find the way on. Descending for one final hunt, he'd suffered a bit of an equipment malfunction, loosing most of the air from one cylinder and his GoPro. Returning to the chamber, he managed to sort the problem and descended again to head out, fortunately recovering the lost GoPro as he picked up the line towards the exit.

Safely back to the streamway, with dry land to sit, Andy set about tinkering his kit while I made a final enlargement to the hole I'd been digging and wriggled into virgin passage. After about 10m of progress in the low streamway, I met anther silt bank blocking the side of the passage. This was dispatched in about 5 minutes and another 5m of progress was possible until another silt bank blocked the way, though the streamway was a little larger by this point. By this time, energy levels and enthusiasm were running thin and I called it a day, with a further 15m of open passage in view and no end in sight. Somewhere more accessible, this would be a great prospect that would attract attention, but beyond 6 sumps in Otter Hole, I can't imagine anyone will be poaching my dig any time soon!

Andy returns through the duck

Returning to Sump 6
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Returning to Sump 6
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Since Andy was still kitted up, he dived out first while I sorted myself out, taking my time to allow the viz to clear; little good that did though as I came out through Sump 6 completely blind with nothing more than a brown glow for company. Visibility improved to about 0.3m in Sump 5 and I spotted an old dive line emerging from a silt bank; I'd seen this before in better viz and knew it went un-belayed back to dive base, so took the opportunity to cut it off where it appeared from the silt. On emerging from Sump 5, we pulled the tangled old line out, cabled tied it into a bundle and stuffed it into a bag to remove. Fins and lien reels were returned to their "washing line", hung up above anticipated water level ready for the next attempt (they are not needed in the shorter sumps further downstream).

Progress back to Sump 4 was deliberately steady, heavily laden with kit, yet despite the utmost of care, I still managed to take a fall, when a pinnacle of rock I was leaning on broke off; I pitched forward hitting my chest on the remaining stub before falling backwards and taking a hit to the thigh as I landed, but I managed to prevent any impact to the diving kit, that we still needed to get out. Fortunately that was the only drama and it wasn't long before I was weightless (and blind) again heading back out through the final three sumps. Chatting on the way out, we guessed that Sump 4 would probably encapsulate most people's worst nightmares, an awkward squeeze to navigate, underwater and in zero visibility, and all hours from the surface, yet in the moment, it is bliss. All the effort of dragging kit evaporates as you become neutrally buoyant, the sweat and grit washes away and at last, you can cool down and relax for a short time, before the punishment of caving resumes.

Back beyond the sumps, we took our time sorting and packing kit, deciding what was to come out and what was to stay in for next time. This was the most faff of the day and we both knew why; it was going to be a long hard slog from here and we were delaying the inevitable. I managed to squeeze a 3 litre cylinder into my bag; it was going to add to the weight on the way out, but it's been in the cave for over a year and I'd be glad to have it back out. Final preparation for the exit journey, a drink of water and a bag of pork scratchings, then time to move.

The tidal sump had dropped below the eye-hole by the time we arrived back at this point, but it was still pretty full, allowing us to cool off. Again, we faffed and chatted a while in the water before pushing on up the slope through the knee-deep tidal mud. Having hardly stopped since leaving dive base, now we were on the home straight, the rest stops became more frequent as we slowly pushed through the bedding planes towards the exit.

Andy coming through the tidal sump
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Taking a breather
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Moving bags through the bedding planes
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The final squeeze
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At five past six, just over nine hours after we entered the cave, we finally dragged ourselves out into the humid heat of the evening, whereupon the camera lens immediately steamed up, as the obligatory post-cave picture attests. All that remained was the long slog back up the hill, until next time...

Out at last
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P. Hall, A Torbet
 

Flotsam

Active member
Very pleased to see further discoveries being made, an already great cave made greater. Very sad to know that damage has ocurred.
I did a very early photographic trip into Otter hole, around 1976. I have some 20x16" prints of exhibition quality if anyone is interested, not sure if I still have the negatives unfortunately.
 
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