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40 - 50m range difficulties.

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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100 % H2O
Feb 5, 2002
I'm sitting with a Pb Of 45m. I have been here a few times. Each time i have no equalising problems and plenty in reserve when i surface.
From 0m - 42m the dive feels the same in the respect that there are no detectable changes in my body.( at 40 m i could just as well be at 10 m)
From 42 m however i start getting a strange disconcerting effect. Till now i have been able to ignore it for 3m and just punch to the 45m mark grab the tag and as soon as i turn up-right it goes away.

What happens is an involuntary spasming having its origins in the diaphragm /chest/ throat or soft - palate? im not sure but its negative effect is felt in my upper tract / soft - palate. The spasm is rapid and communicating with my mask. By that i mean that i seem to pump the mask in and out rapidly involuntarily and raspily.
It is not a sensation of my lungs touching or wanting to cough or a tickle.
If you have ever heard the sucking sounds a person with hayfever makes, this also happens in my upper tract/ throat/ soft - palate, but fast and raspy in and out.
These contractions / spasms ? are very rapid and ragged in frequency and onset suddenly. I would like to have some advice on what they are ( surely not ordinary contractions ? ) and how to deal with them before i move on deeper. They tend to throw me out of the groove.
I usually arrive at 42m in around 30 seconds with a mono.

Any advice appreciated.

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I have no advice but I wish I could dive that deep your lucky. And 30sec to 42m wow, it takes me 1:20 to 18m and back your cruising man :cool:

40 - 50m Difficulties

The consistency of the depth phenomenon with respect to the depth at which its onset occurs suggests to me that it is the result of squeeze moving your anatomy around in such a way that some nerve is being stimulated by contact, or by stretching,
or some other deformation of the usual shape of things. Some pressure receptor that is not used to getting stimulated is saying "Hey ! What the hell is THIS ? "

Could be it is very much like a hayfever sufferer's spasms, in the sense that some nerve that is not used to being 'tickled' is getting tickled.

If that is the case, the solution is probably habituation - frequently revisiting the critical depth and gradually, incrementally pushing past it in baby steps.

Just a thought.
It may be due to your lungs being uncomoftable at low volumes and you getting a breathing contraction - do you get the same effect from doing empty lung dives in the pool?

If not then I've no other ideas at the moment!

Hi Ben

I usually dont do negative dives. I have hurt my ears doing easy 5m negatives. It didnt even hurt but the next day my ears were blocked and the doc said there was fluid seeping out of one of the eardrums.

I always do negative statics though and apart from the lack of air and the feeling that im gonna pee down my leg any moment they pose no similar problems.


Another thing. When packed i have a VC of 10 L. If meeting residual volume occurs at about 40m i would expect to be exempted from this for a few meters more 50 m perhaps ? So i'm not so sure that its the compressing of my lungs to residual threshhold thats affecting me. Also turning upright stops it dead.:confused:

I can ignore this and keep going. but i'm not sure if it will pass or get worse I think its prudent to understand it before going for 50m.
Hi Skin,

I suffer the same spasms, but only during negative pressure dives at the pool. If I do to many reverse packs I get the spasms. Some are worse than others and one dive is different from the next. I haven't been deep enough to have it happen in the ocean "yet", but I'm sure at some point I will.

I think Ben is right, but I understand what you mean about it's not a "regular breathing reflex", but I do beleive that it is due to the discomfort on the lungs and diaphragm.

I do lots of negative pressure dives in the pool to help get used to the feeling, but they don't get better or go away.

Try packing a little more.

My $0.02

I have spoken to a great number of divers who experience 'disconcerting' effects as they pass the 'wall' around 38-45m. Each diver describes a slightly different problem, but each diver says that 'something happens' in the chest or throat, which feels weird and disconcerting, and this weird feeling results in a simple instinct; TURN AROUND NOW!

When I first had this problem back in 1998 I asked Rudi Castineyra, and he told me that he had never met a diver who DIDN'T get this problem.

Peppo Biscarini described it as a crushing of the oesophagus (the oesophagus actually folds down the middle around this depth).

Some people actually experience injury/damage if they continue past this phase. For others, the barrier is more psychological.

I get this feeling on every dive as I pass about 43m, and each time it tells me to turn around. Each time I continue anyway, because I know from experience that the feeling goes away eventually (or maybe I just get used to it).

So, DSV, at the very least you know that you're not alone in this problem....

Eric Fattah
BC, Canada

Wow deep diving sounds like really scary stuff guys :naughty

Hi Skindiver.

You really want to be doing negative dives to get used to the feeling of pressure. If you can't equalize your ears then I suggest you learn the mouthfill technique that Eric has written up. You will need to know it anyway once you start diving 50+ meters. Then over time build up the amount of negative packing you do, and therefore more 'simulated pressure'.

I live 2 hours drive away from the sea so I have done most of my training in a pool. Negative pressure dives have been vital for me to get used to the feeling of pressure ie lung squeeze. Whilst training in Hawaii I did several dives between 52-61m. I'm not sure I've had the sensation you described, I just notice the lung squeeze on a deep dive or deep negative dive. I describe it to people as "It feels like an Elephant standing on your ribcage" :duh

Re: Negatives

Originally posted by Skindiver
. When packed i have a VC of 10 L. If meeting residual volume occurs at about 40m i would expect to be exempted from this for a few meters more 50 m perhaps ]

Hey Skin, if you're packing to max and getting this reaction at X depth, then theoretically if you dive on normal lung volume you should get this reaction at a shallower depth (?)
If this were my situation, I would dive on "normal" mode to acclimate myself to this reaction at a shallower (and safer) depth. It would take less time too.
I don't get the same feeling you get, but I do get very strong psychological "doom" warnings, which serve the same purpose I suppose: to make us progress slower than we would like!
Erik Y.
The deep thread


I call this the deep boys thread, all this talk of elephants standing on me at 50m :D Im glad im a shallow diver. Seriously guys keep it up great thread :cool:


Its good to hear its not just me.

Thanks Erik. Great idea. I will even do some half lung dives to see if i encounter this phenonemon at say 20 - 25m and learn to cope with it at a less critical depth.
Efattah thanks too. I feel a bit better about putting my head down and punching through it and hopefully hitting the bottom of our quarry @ 54m.

I have six weeks with probably a maximum of three weekends there- in to do it.

Skin !

When I get to 42m, it feels like someone hits me on
the throat with a lead pipe.

Never thought of it that way, but I can feel my throat
closing up, or like eFattah said, folds up.
At that stage I just close my eyes, pee in my pants, and go for gold.

Its a sudden change, but it doesnt get much worse with depth.

PS : Ill see you at the bottom !

Ja Mr H

Ek sal jou op die bodem sien. Ons moet daai ou Duitser iets wys ne' ?
Die jaar gaan die Statics die wenner aandui, nie die duik nie. Dis n' pity want ek hou nogal baie van jou glas en hout diep duik trofee..:)


I have solved my problems.

The wall i encountered at 42 m was not the classic wall ... but was a cold thermocline.
This is one thing but my descent was way too fast and i nearly died when i punched this thermocline at such speed. I gasped and set off an uncontrollable gasping spasm.

Yesterday i slowed the descent down by gliding after 5 kicks only and penetrated the thermocline in an anticipated slower way. The problem did not recur and i turned easily at 50m. YAY!

I estimate that gliding down instead of kicking down has added some 10 - 15m to my depth ( judging on how easily i equalise and how i felt at 50m and again at the surface)

Now i have a real wall.. at 54 m in the bottom of the quarry. Things are getting to be a bit too shallow in my fave hole...
Can't wait for Cyprus now..

Skin ( The 50m man :) yea!)
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Hahaha well done mate :)

That's a big difference you mention - an extra 10-15m just by gliding... what level are you neutral at? What level do you glide from? How has your dive time changed with distance?

Once again, well done mate, all the best for the future and Cyprus :)
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Dive time

Hi Loopster

My previous PB was 45m. I did this in 1.07 ( yes flying ) with Cressi Gara hf's. My descent time and my ascent times were the same. 33 - 34 seconds each.

With a hard Sebak Mono however whilst i can go much faster i have learned to glide down slower. 5 Kicks brings me to about
- 15 m after this i glide the rest of the way. the rate works out to about 1m / sec. so i reached 50m in 50 sec.
The calming effect of gliding on oxygen preservation is remarkable in comparison to kicking all the way. I imagine much like doing a 50m dynamic in 50 sec or just doing a 50 sec static. Chalk and cheese.

I have my theories about anaerobic ascents so i take off like a homesick angel and reach the surface after 30 seconds. Total time 1.20.

Also interesting is the kicking style on ascent. No big kicks. Millions of small high frequency low amplitude kicks like a vibrating just shot fish. Big speed and low fin profile and low exertion.

I'm fresh and clean at the surface, not even a hook breath needed before many victory 'whoops' and ' i.. am.. your.. automatic.. diver..' exclamations complete with pelvic thrusts etc ... :)

I could post the Suunto Stinger graph if i knew how.

Skin _50
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I'm a fast learner

50m gliding profile.



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Which SEBAK do you use skindiver?

I use the models, "Peter" (my own) or "Teppo", with the angle and the OMER pocket and it's remarkably nice especially on the gliding phase of the descent.

I have the same time as you to reach 50m but the ascent takes about 45sek so my total time on a 50m dive is around 1.33-1.38. I also use small kicks and I have found out that for me this kind of techniqe suits for this fin, it feels more natural for the body than kicking with bigger strokes which I do with a normal mono without angle.

My opinion is also that the ascent of the dive should be faster than the descent but I don't like going as fast as you do skin, maybe because you are a better monofin-swimmer than I am.;)

This SEBAK fins felt different in the beginning, especially on the "backstroke", but after some training I would not consider going back to a normal mono.
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