Main chamber vs Titan

[Samouse1]

A question was brought up over dinner, as to which of the two had a greater volume. Having been in both, I assumed that main chamber was bigger, but have heard it argued both ways.
I know Main chamber has been laser surveyed; has something similar been done in Titan, or would one have to work on estimates? 

[Pitlamp]

GG Main Chamber has been laser surveyed but this didn't capture most of the great rift high up between the Rathole shaft, lateral Shaft and Main Shaft (due to droplets in the showering water disrupting the laser beam). If you've never visited this great rift you might not appreciate its size. If comparing GG with Titan (which is a shaft with a large top half, above the Event Horizon) you need to include the GG great rift to allow proper comparison. There is an article in a Descent magazine from a few years ago which points out that the volume of the great rift considerably adds to the volume achieved by the GG laser survey.

I' think Titan has been laser surveyed - Moose will probably be able to help if he sees this. But don't forget there's another 30 m depth of boulder filled shaft below the floor of Titan, leading down almost to Far Sump level. Then again, some geophysics done in GG tells us that the true floor of the Main Chamber is up to 30 m below where you land after abseiling into it. As GG has a much large floor area than Titan, if you include the buried part of GG it's probably bigger than any other known karst void in the country. If you don't include the buried parts of GG, Titan - and other possible contenders, then it's a much closer run thing.

What no-one disputes is that Titan is by far the deepest natural pitch in the country. GG isn't even the deepest in the Dales - Vulcan Pot (in Nick Pot) is deeper than GG.

[Samouse1]

Good info Pitlamp, really puts into perspective how big main chamber really is. Found a cracking video (featuring some familiar faces) exploring the 3D map that was made, and see what you mean about there being a huge rift. I've personally not had the pleasure of descending into main chamber so have only seen it from the floor, so that blew me away. Two different beasts, bloody impressive in their own rights.

[Pitlamp]

Reckon you've hit the nail on the head there Samouse1; all these big karst voids (GG, Titan, Charterhouse, Time Machine, Frozen Deep) are stunning places to visit and attempts to put some statistic on which is biggest or best in some way is never going to be entirely meaningful. Far better we recognise what a fabulous karst resource we enjoy in the UK and celebrate it all.

 

[mikem]

Calder's Geo sea cave in Shetland has a bigger area than Frozen Deep, no idea what the depth is underwater:
https://www.bbc.co.uk/news/av/uk-scotland-28967037/eshaness-sea-cave-is-largest-in-britain

[Samouse1]

The sea cave may be impressive, but it's not karstic, and you cant walk around it, not nearly as fun if you ask me. 
I've heard rumour that Powells lode in north wales wants to claim largest chamber, if you include the lake...

[mikem]

No, but you can kayak around it, which is more fun than walking...

[cavemanmike]

Or dive it, which has been done

[nearlywhite]

I've heard rumour that Powells lode in north wales wants to claim largest chamber, if you include the lake...

It's mostly filled in, only half the chamber and only 42m deep... It's still a hell of a place to go though

[Russell Myers]

Quality over quantity anytime - GG beats everything else into a cocked hat (or should that be a soggy papier mache miners helmet) for the sheer majesty of the place and I would put Dihedral Route into it as one of the best routes in the Country if not at the top of the list.

There again I am biased. 

[Alex]

What no-one disputes is that Titan is by far the deepest natural pitch in the country. GG isn't even the deepest in the Dales - Vulcan Pot (in Nick Pot) is deeper than GG.

I dispute the last bit it lol, Vulcan is the deepest underground pitch at 98m according to NFTFH, however that does not mean it's the deepest pitch. From what I can tell main shaft, is also 98m deep according to the wiki, so joint deepest in the Dales maybe. The wiki then goes onto say the Jib tunnel descent is 104m, so I am not sure which is right, but that puts it at 98 - 104m.

On the Craven website of exploration it notes the depth was measured at 365 feet which is 111m.

On Breamore website it says "10 m down the shaft, the diverted Fell Beck water can be seen entering on the left, at 98 m forming the highest waterfall in Britain" meaning the shaft is 108m.

In any case each one of these is equal to or greater than Vulcan pot depth, but it's interesting there is no consensus on the actual depth, with Gaping Gill being between 98 and 111m

[mikem]

It very much depends where you are measuring from...

[langcliffe]

In any case each one of these is equal to or greater than Vulcan pot depth, but it's interesting there is no consensus on the actual depth, with Gaping Gill being between 98 and 111m

I wouldn't take Dick Glover's figures too literally, but you may be interested in:  Cordingley, John (2002). "The True Depth of Gaping Gill". Cave and Karst Science. 29 (3): 136.

[Alex]

Available on-line?

[langcliffe]

Available on-line?

Easily found: http://cavescience2-cloud.bcra.org.uk/3_CaveAndKarstScience/cks087.pdf

[Alex]

Thanks

[mikem]

Of course GG's floor isn't solid, is Vulcan's?

[langcliffe]

Of course GG's floor isn't solid

It's a lot more solid than me. I wouldn't like to land on it from 98.1 metres.

[AlexR]

 

I would say the floor of Nick's Pot is as solid as the one of GG Main Chamber. To what depth the rubble goes, I have no idea.

[Alex]

Aye rubble slope on both and Nick pot slopes downhill from where you land, so where was it measured to I don't know either. My point is I dispute that GG is not the deepest in Yorkshire and can be argued.

[Alex]

Meant to say might not The linked document measures it to 98 too.

[andrewmc]

Also there is no clear free hang from the main shaft entrance to the floor. The 'main shaft' route drops most of 10m then traverses a few metres to (just) miss Birkbeck's Ledge, so the pitch itself is only about 90m or less, whereas I'm told you can do Dihedral without the deviations or rebelays (if you don't mind drowning) which may/may not be a larger pitch? I haven't done Dihedral (only the main shaft route) so I don't know which is actually the bigger (possible) pitch...

[langcliffe]

My point is I dispute that GG is not the deepest in Yorkshire and can be argued.

You may well be right, but I don't know of any attempt to measure the depth of Vulcan with the same accuracy as Pitlamp's measurement of the depth of Jib Tunnel, so I really don't think we have sufficient data.

[Fulk]

whereas I'm told you can do Dihedral without the deviations or rebelays (if you don't mind drowning)

You can get a free hang from the top of the Dihedral-Route shaft; I've done it once (down and up) on a warm sunny day in fairly dry conditions, and the last 'lots of metres' was a tad damp.

[Ian P]

whereas I'm told you can do Dihedral without the deviations or rebelays (if you don't mind drowning)

You can get a free hang from the top of the Dihedral-Route shaft; I've done it once (down and up) on a warm sunny day in fairly dry conditions, and the last 'lots of metres' was a tad damp.

I thought Dihedral “direct” was “Jib”

I have done it quite a few times but only when there is a “ chair” waiting at the bottom. 
Last year at the winch set up We went down in “ normal” water levels and was really wet lower down. Far wetter than previous years in similar water levels.

I think getting back up would have been extremely unlikely.

Fantastic pitch to do occasionally.