I've been lucky enough to work for three resort operators, at 4 neighboring resorts. Each operator had/has 4-5 operational scooters, and due to leading scooter dives on a regular basis, I knew which scooters and batteries were the most dependable (or the fastest

).
At all 4 locations I regularly took off on solo scooter dives, mostly slow afternoons, but a few slow mornings and mid-days too. Operator #2 had 100 cft's at both locations and #3 has a couple lp 95's that sometimes have 3000 psi. :shocked2:
All I can say is since I know I can get tourists to the St. Anthony in 13 minutes and it is ~400 yards off shore, a half hour straight out is over a half a mile off shore. Well I guess I could also say that there are some overhangs on the off-shore side of the deep reef more than a half mile off Wailea beach that are at 125 fsw.
Here is my math on the risk;
dead scooter half mile off shore - head to shore ascending to SS depth, swim back towards shore @ 15' towing scooter until low on air, surface swim the rest of the way; current might mean I land in Makena but I will make it to land.
catastrophic gas situation half mile off shore and 125' down - scooter powered ascent no faster than 60 fps, then backside surface superman-ing to shore.
I have ended up with a very weak scooter at the St. Anthony, and two guests. I kicked the weak scooter to shore but could not maintain course due to current, so we hit shore 1/4 mile south of my target; had to comp that trip. :depressed:
When this octo grabbed my reg at 80 fsw, more than 500 yds off shore, that's the only time I had second thoughts.