Poll: At what tank pressure do you plan to end your dive and ascend w/ safety stop

[Griffo]

I used to be a 500psi guy, but one of the best things I learned from my GUE Fundies course was about actually calculating this number. It really depends on tank, buddy, depth, dive profile and consumption rates. It's still a relatively new concept for me, so my math isn't as fast as I want it to be, but intend to actually calculate how much air is needed to safely surface.

+1. Except I live in a metric world where the maths is simple enough to do in your head reliably. BAR, liters and pressure in ATA's. ATA's are simple to work out from depth - anyone can divide 30m by ten to get 3 and add one to get 4 ATA's. 200 Bar in an 11l tank is simple to work out 2200l of gas. Average sac of 20 liters per minute. Etc etc

I'm not sure I could work out imperial without a calculator

 

[dumpsterDiver]

Free ascent, mid-level current? You need more air.

Nice anchor line? Less air.

In general I would disagree. When anchor diving, you need to leave enough air to get to the anchor, For drift diving with a free ascent, you can begin your ascent whenever you feel like it.

Even if we disregard the necessity of locating the anchor line, it can be much more strenous climbing up an anchor line in big seas and strong current, while a free ascent can be perfomed with negligible exertion.

 

[Carlos Danger]

depends on the dive profile.

On a shallow dive at my local watering hole, I will head up at 500psi or possibly a bit less.

On a deeper (rec) dive, I will plan on being on the surface with 500psi

On a dive charter, if there rule is back on the boat with 500psi, I will follow it.

I generally don't use the alarm settings on my computer, and just monitor my supply

Agree!

 

[EMiles]

As was stated previously, it depends on a lot of factors: Your SCR, your buddy's SCR, your depth, your tank, ascent strategy (direct ascent, out and back, hard overhead). Rather than calculate rock bottom on the fly every time I keep a table in the back of my wetnotes for various depths and tanks I use (Double HP100s for local dives or AL80 for vacation). This table shows me need cubic feet and the tank PSI for a given depth. Rock bottom changes on a multi-level dive so as I go up I can see how my rock bottom changes (pretty much memorized by now). Anyway, here is the table (again, assumes direct ascent, an emergency SCR of 1 cu ft/min for two divers and a GUE/UTD ascent profile).

Depth CuFt HP100(x2) AL80
40 13 200 500
60 19 300 800
80 31 500 1,200
100 40 700 1,600

 

[Doc]

I dive in some pretty far-flung places, thus almost always with a DM.

After a nice gradual (no deco) ascent, I tell them that, as a bare minimum~ if there was something worth seeing and staying so long... I want to be under the pickup boat in 35fsw with 300psi.
I know, I know-:scared:the horrors!