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Dive comfortably

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
Jul 10, 2003
There is a simple way to know what is the perfect depth to hunt. You just have to realise that to dive at 15, you should hold your breath underwater about 1’’15’.

So, you just have to perform a simple exercise.
Start walking at a medium pace for 3 minutes, then hold your breath and take your maximum.

Know just do the following:

(X * 15.5) / 75’ = MAX.DEPHT TO HUNT

X=Maximum breath hold while walking at a medium fast pace.


35 seconds = 7 metres (22 ft)
50 sec = 10 metres (32 ft)
75 sec = 15.5 metres (50 ft)
90 sec = 18 metres (59 ft)
120 sec = 24 metres (78 ft)

Remember that when I say hunt it doesn’t mean dive, touch the bottom, and surface again. To hunt means that you have to explore a little the bottom…

120 seconds for a freediver is enough to reach the 30/ 40 metres.
Hi CC,

Interesting idea, seems to be approximately correct for me.

Hello CC,

I think you have missed something.

IMO if one can walks for 30 seconds and he can dive for 30 seconds that does not mean that if one day he can walks for 60 seconds he can dive for 60 seconds. On the surface one can operate with more air to gain oxygen from than down below. The reason is that some amount of the air is passed from the lungs to the middle air.
Ofcourse other mechanisms actuate below the surface to help us
endure more but those ones make the equation even more complex.

Anyway I believe that the formula you give works for you and maybe for many others but I think it is an exception useful only in limitted depth.

Dive safe,
Originally posted by sea-wolf
. On the surface one can operate with more air to gain oxygen from than down below. The reason is that some amount of the air is passed from the lungs to the middle air.

huh? I assume you are talking about lung volume? Whats the middle air?

Whilst the lung volume shrinks during a dive, the amount of oxygen, ie the number of moles, doesn't. So you have the same amount of oxygen wether you are holding your breath at the surface, or down below.

Oxygen use at depth may well be more effective as some is disolved into the blood plasma due to the partial pressure law, and the reduced lung volume means diffusion operates faster given the same concentration gradient, as distance is reduced.
Hello Shadowkiller,
Excuse may not so good English - I have mistaken the word ear with air. I mean the air needed for equalizing the ears.

Safe dive,
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