Author Topic: Longest single entrance underwater cave in the world?  (Read 1111 times)

Offline Pitlamp

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Longest single entrance underwater cave in the world?
« on: November 16, 2017, 04:49:59 pm »
I was asked recently if I knew what is currently the longest single entrance underwater cave system currently explored. I couldn't answer this myself, hence asking on here. The longest suggested was the Ixtlan System at Quintana Roo (Mexico) at 15.43 km.

Does anyone know of a longer one?

(It's probably best to stick with completely water filled caves with only one entrance, rather than being side tracked by other categories such as "total length of sumps" or whatever.)

Thanks, if anyone can help.

Offline rhychydwr1

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Re: Longest single entrance underwater cave in the world?
« Reply #1 on: November 16, 2017, 08:46:57 pm »
Ixtlan System at Quintana Roo (Mexico)

I cannot think of anything longer.

Offline ah147

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Re: Longest single entrance underwater cave in the world?
« Reply #2 on: November 16, 2017, 09:18:28 pm »
Just to mess this up, that's not the furthest distance in the system.

That's the total length of passages.

So is it really the "longest"?

What I'm trying to say is you can't set off and swim for 15km along a single line constantly heading away from the entrance...

Offline Pitlamp

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Re: Longest single entrance underwater cave in the world?
« Reply #3 on: November 17, 2017, 09:10:15 am »
Thanks ah147; to be honest I'm not entirely certain myself what the criteria are; I posted the question on behalf of someone else. I suggested they keep an eye on this topic and, if I get further clarification, I'll add it here.

Online Benfool

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Re: Longest single entrance underwater cave in the world?
« Reply #4 on: November 17, 2017, 11:08:23 am »
caver bob has a list of the longest underwater caves that might be useful:
http://www.caverbob.com/uwcaves.htm

although if you want something more specific than simple length you'll struggle!

B

Online alastairgott

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Re: Longest single entrance underwater cave in the world?
« Reply #5 on: November 17, 2017, 11:43:01 am »
So is it really the "longest"?

You just want to be the one who's had the longest penetration!?!

Doubt there will be anywhere you can park a scooter.

Offline MJenkinson

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Re: Longest single entrance underwater cave in the world?
« Reply #6 on: November 17, 2017, 01:41:55 pm »
The caves in Mexico are like a maze, you will struggle to get a nice definitive answer on any sort of "what length is the longest dive". You could come up a million convoluted ways to do huge dives.  The caves are not like say those in France which are more "straight forward" with regards navigation (sweeping generalisation I am sure).  The lengths are total surveyed passage so yes, you probably can't get 15km away from the entrance.

I'd actually be surprised if the longest single entrance cave was in Mexico - there's just too many entrances in these systems.

And you are really going to struggle with the whole one entrance thing.  To be totally submerged means that you can only do an in and out dive and then end would have to be a definitive end underwater.  So that rules out Pozo (longest sump goes to air), Ressel (same reason)...

How long is that place we're mot allowed in...in France...near someone's house...Doux de Coly, that's the bugger.

Offline Pitlamp

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Re: Longest single entrance underwater cave in the world?
« Reply #7 on: December 06, 2017, 07:05:58 am »
Thanks all - yes, I also immediately thought of all those ifs & buts when I was asked the original question. That's why I decided to post it here, to see what others thought.

I suspect the answer is - it's a very difficult question to answer (and any answer which doesn't explain the situation in detail is probably meaningless anyway).

If anyone has further thoughts to contribute, please do add to the above. I'll go back to the person who asked me and direct them to keep looking at this topic.

Offline MJenkinson

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Re: Longest single entrance underwater cave in the world?
« Reply #8 on: December 06, 2017, 09:59:41 am »
OK...

Having had another think about what is excluded under the terms "fully submerged" and "single entrance" (Which is quite the list - Pozo, Ressel, most of Nullabor, most Mexican systems, upstream from Cathedral in Florida + Altantida tunnel (the latter as there are others longer)..

My money is on Doux (5.6km, straight shot, ends underwater).  You would need a decent survey of the Mexican system to get a "gentlemans" agreement on what the longest passage is.

Offline apitkin

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Re: Longest single entrance underwater cave in the world?
« Reply #9 on: December 13, 2017, 03:02:24 am »
The system has more than one entrance but Cathedral (Ghoul Sink) is the most upstream entrance of the Falmouth-Cathedral System and has been explored to a distance of 8.2km upstream from there, all underwater.

Nearby, Lineater has been explored to 6.4km from the most upstream entrance and is also still going, parallel to Cathedral.

Andy

Offline MJenkinson

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Re: Longest single entrance underwater cave in the world?
« Reply #10 on: December 13, 2017, 12:45:01 pm »
I did consider Cathedral but wrote it off as the survey i found only showed 5km - obviously an old one. Bosh. Do we have a winner?

Offline alexchien

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Re: Longest single entrance underwater cave in the world?
« Reply #11 on: December 13, 2017, 02:00:03 pm »
"explored to a distance of 8.2km upstream from there, all underwater"

Pozo actually has a sump (S2 + S3) which is close to this distance (8125m and possibly longer) as it is in fact one long sump. Tipperary is just a side passage (oxbow) with an airbell.
All active waters travel via the underwater route.
Yes, the underwater connection (S2-S3) has been proved and lined.

The only difference here is that this sump is not located directly at the entrance, but starts 1km in.

Offline apitkin

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Re: Longest single entrance underwater cave in the world?
« Reply #12 on: Today at 12:12:40 am »
 :) It all comes down to definitions.

Falmouth-Cathedral is a multi-entrance system, so it doesn't really count for the OP's purpose.

The end of the line in Cathedral is (I believe) the longest linear penetration from an air surface in the world, and the cave is still going.

Offline rhychydwr1

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Re: Longest single entrance underwater cave in the world?
« Reply #13 on: Today at 09:29:23 am »
:) It all comes down to definitions.

Falmouth-Cathedral is a multi-entrance system, so it doesn't really count for the OP's purpose.

The end of the line in Cathedral is (I believe) the longest linear penetration from an air surface in the world, and the cave is still going.

Is this in Cornwall?