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Dynamic=CB system?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
May 9, 2003
I remember reading a system to convert dynamic distance to
possible CB depth. It was about eight months ago in one of these threads. Anyone know what I'm talking about?
I remember that I plugged in my #'s and it was right on.
Dynamic = (4/3)CW + 22

i.e. 50m constant weight:

Dyn = (4/3)*50 + 22 = 88.65m

Of course, it is only a weak approximation and doesn't hold for everyone.

Eric Fattah
BC, Canada
Can I use this equation to convert the dynamic without fins distance to possible CB without fins depth???

I never considered no-fins when I made the formula, but in my case it works almost perfectly:

pb dynamic no-fins 67.4m (50m pool)
pb cw no-fins 35m

Dyn = 35*(4/3) + 22 = 68.6m

So, in my case it is off by 1.2m (I suck at no-fins!)

However, I think you must use a 50m pool for your calculation, otherwise you gain too much of an advantage from all the turns, which don't exist during your dive.

Eric Fattah
BC, Canada
I've found that multiplying DWF by 3/4 gives a reasonable estimate for DNF, assuming reasonaby good DNF technique. Fudge it up a little for excellent technique, down for poor technique.

my original spelling was less than exellent (sic)
Last edited:
Thank's Eric for your answer.

Hey pezman, for me your equation is perfect!!!!!!!!!!!!

PB DWF: 100mts
PB DNF: 75mts

100 x 3/4 = 75
I'm attempting to decide how deep I should announce
for my first comp. CW dive. I've never done CW before, just
swam around until I needed air. What happens if you go deeper than you say you will?
a You don't get any more points.
b You may compromise the safety of the safety diver(s).
c In one meet they disqualified divers for it, I heard.
Ask the judges at the briefing.
I think that the DNF=3/4 DWF generally gives an answer w/in +/-10%

Majo, I'm guessing that you swim in a 25m pool ;)
Originally posted by ramstam
I'm attempting to decide how deep I should announce
for my first comp. CW dive. I've never done CW before, just
swam around until I needed air. What happens if you go deeper than you say you will?


Bill is right. You don't get any more points for going deeper than your announced performance. Besides, if it's a competition under AIDA rules, you will be required to wear a lanyard which will prevent you from going below the bottom plate.

If I may make a suggestion: Don't try to extrapolate how far you can go in dynamic into how deep you SHOULD go in CW. Going deep is easy, coming back is hard. If you have never done CW in competition before then don't go for a depth you haven't been to comfortably, otherwise you may go beyond your limits and lose all your potential points. If you can dive only 3m, then do it really, really well and get your points for that event. You will be better off than to try for 30m, black out, and end up with nothing.

Peter S.
Does anyone know the formula for how deep I can go on Unassisted freediving (no weights or fins) if my PB in DNF is 40 meter?
According to Eric's formula, 6 meters, but I think that the formula fails when there is little or no "free-fall" in the dive.

Assuming that your DNF is about 30m, then your CBNF limit should be no greater than 15m.

So somewhere between 6 and 15m ;) ...

I am going to guess that you should be able to do at least 10m and might be able to do as much as 15m -- beyond that, you start to get a little heavy at depth and the amount of effort required to get back to the surface goes up pretty dramatically.

It would be interesting to compile a list of stats from people and then use a curve-fitting program to get these kinds of estimates. My guess is that a 2nd order curve would give pretty good results. The CAFA site, FreedivingSpots.Net and most meet results have data that could be used for data, and Excel has curve fitting add-ins.
I wished I could find a formula to overcome my equalization problems... (yeah of course mostly mentally you d say) to convert my dynamics performances into depths...
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