Yeap, FRC is Functional Residual Capacity, i.e., passive exhale.
For those of you who might wish to extrapolate what that might equate to as a TLC (buccal) no-limits dive, the solution is much more complex than it may seem.
Doing RV dives to say 35m is physically more stressfull than a TLC dive due to the short time course to max pressure, i.e., the pressure gradient is extremely steep, very quickly. Because of this during FRC or RV dives the the 'blood shift' is incomplete. It's a bit like sucking air out of a straw very quickly; it leads to collapse of the veins and a pressure limiting dive. This is not the case for a TLC dive due to the extended dive time to promote blood pooling.
On the other hand there is greater loss of lung gases due to absorption as a result of extended dive time and ambient pressure during TLC dives.
This is why there can be no clear relation or extrapolation. The only way to measure it is empirically.
In regrads to a depth goal for no limits I have only ball park figures and prefer to dive on familiar physical sensations. I think setting goals like that is inherently flawed thinking since it can set you up for a fall since what you might have been able to do yesterday you may not necessarily be able to do today. My stand on setting tags and goals is like dangling a carrot before the donkey; he's going to go for it everytime but might not make it.
Eric, my [Hb] and Hct are normal and average values, they only increase substancially during dives and then only transiently. I had them done recently but my specs are in Townsville....I'm now in Cairns temporarily. I think my strength isn't there but rather in my aerobic fitness under normoxic and hypoxic conditions, elevated blood volume, strong peripheral vasoconstriction, low resting heart rate (now 33) and good splenic emptying which better helps dilute CO2.
I don't do dry statics now, not ever....not specific enough. But yeh, I have done 3'30" forced negative dries before. The only statics I now do are wet and deep FRC dives or, RV dives if I'm restricted to shallow dive sites. I don't hyperventilate..... well maybe just one last sigh before diving. I don't go to contractions during deep dives as the dives aren't long enough e.g., 2'30" @ FRC & 2' @RV. In the pool, I now only do FRC dives, whether static or dynamic. The reson being I recover faster and can positively stress the system without fear od SWB. SWB is not just about partial pressures but changes in lung volume too. I've never come unstuck diving this way, not ever, even on bad days. I think if I did negatives to depth with contractions it could cause excessive pulmonary stress, e.g., oedema. It's ok and tolerable in the shallows or dry because the blood shift isn't fully manifest.
I don't do static FRC or RV dives to the limit but prefer to take them to the first contraction (best of 2'45" @ -3m first contraction). After a few I'll do 2'00" static + dynamic (best of 3'10" total bottom time and 100m distance)
Prior to doing static + dynamic training I'll, typically, do:
+50 x 50m dynamic in >35-40" (swimmer's rubber fins) with 1' recoveries. Very stressfull, but very good for fitness and relaxation training under stressfull conditions.