Bottom times...depth...etc....
Diving for fun is a much different psychological mind set for me than deep diving. When I'm training on the line, I have a goal in mind but I try to cultivate a hyper-sensitivity to my own physiology and psychology. I've learned this from diving with Eric Fattah, watching him do this for himself and also having to be attuned to his state of mind and body as his training buddy. Several times I've picked up that things weren't completely right and confirmed them with him--we would then modify our plans.
So having a goal of hitting a target depth is more like a suggestion and I wait for an answer from my body and mind. As if I say to myself, "I'd like to dive to 51 metres today, what do you think of that." If the reply I get is "well, I don't know, your breathe-up sucked, or you were up late last night and not 100%, you know, or you have a bad feeling in general" then I shorten the depth or forgo it altogether. Once I felt bad one day, decided to not do any deep dives past 15m and the next day I came down with the flu. Since my body was already busy fighting the virus, oxygen was in short supply.... I really enjoy setting personal bests, especially in constant ballast, but I enjoy getting to know my own mind and body even more. I have gained a lot of confidence from listening to the tell-tale signs. So far I've had no blackouts or sambas... and I hope never to have either.
When I recreational freedive to see things and enjoy the feeling of moving in any direction at will, fast or slow (you guys HAVE to try a monofin!), I stay well within my limits. I rarely push dives to the contraction point and recover for 3-4 minutes between dives. My recreational limit that I've given for myself is 25m and around 1:30-2:00 minutes. I have tried going deeper and staying down longer, but it takes so much longer to recover and breathe-up again, plus the danger of going that deep, that I prefer shallower dives. I much prefer the rhythm of repeated dives between 15-20m with easy ascents and no contractions. Since we dive here in BC with poor surface viz, as Tom Lightfoot has explained, we spot each other on the surface and keep our bottom times conservative and consistent.
I often see freedivers sometimes "dive by the watch." They look at it on the way down to get to that magic depth and at the end of the dive, they're looking at it again to stretch the time out to that magical number. Much better to dive comfortably and be pleasantly surprised by how much time you've spent completely at ease underwater. I use the gauge as a safety device: "whoops, I've sunk to 25-30m, I should cut this one short." or "1:45, time to start up."
Oh yeah, bad idea to practice statics in a hot tub. You're not supposed to stay in them for any length of time anyway. It dilates your blood vessels a lot, drops your blood pressure and makes it a lot more easy to samba or blackout. And wet static goes with a buddy, always. A prospective student of Kirk's got so excited about the Performance Freediving course the next day that he did a static in his hot tub and drowned. He was alone. And it was very sad.
Anyway, sorry for yet another long post and I hope I don't come across like I'm trying to suggest the best way of diving to anyone. Do what you feel is best. Just offering my point of view.
cheers,
Pete
Vancouver, BC