I am not commenting on police or rules but wonder if your wife had a reverse squeeze on the safety stop and needed to prolong it who would have been there. Not the buddy with no air. You should be working as a team. If my husband didn’t follow the guidelines or atleast try to he would be looking for a new buddy and owe me more than a measly dinner.
(Caveat, I have never done this math. I am open to proofreaders and corrections.)
We did four minutes at 18ft. So even though a safety stop might be a non-event from an average of 21 feet, we could claim one. And I wasn't out of air. If we keep air in reserve for an unexpected event, I had 12 minutes of air at 18ft. 14 minutes at 10 feet. Obviously the higher the depth of the reverse squeeze onset the more time I would have had.
I would be curious what your mandatory ending pressure is. The follow on questions are:
Is it the same pressure for a quarry dive as it is for a drift dive?
Do you know how many minutes that is for your husband's SAC, adjusted for 15 feet?
To your point, maybe we should all know our time capacity at the safety stop, rather than a mildly arbitrary psi. Time to react/cope will be different for all of us. For me, 500PSI at the end of the safety stop leaves me with 16 minutes of air, assuming it isn't an event that causes a big increase in air consumption.
This was a good exercise for me so I appreciate the perspective.
Her Tank: (900/3000)x77=23cf of air
My tank: (400/3000)x77=10cf of air
500PSI tank = (500/3000)x77=12.8cf of air
we'll use my SAC since it is the worst. .54 ave over 72 dives.
18 feet of depth = .54 atmosphere
10 feet of depth = .30 atm
@ 18 feet
SAC x ATM = .54x1.54 = .83cf/min
10cf / .83 cf per min = 12 minutes
@ 10 feet
.54x1.30 = .70cf/min
10 / .7 = 14 minutes.
A "normal" end of a safety stop for me, assuming an immediate controlled ascent to the surface, 500PSI @ 15 feet
12.8cf / (.54x1.45) cf per min = 12.8 / .78 = 16 minutes
