3 hours on the water, just enough to enjoy oneself and not get too tired. For some reason I thought you guys were out at some ungodly hour, like past midnight. You used a GPS to get to the spot right? Would it be possible to find the spot at night without a GPS?
I always wish I had a boat with a depth finder and a waterproof GPS so I could find those dive spots that you can't find from the surface. Right now I rely shallow reefs I can see from shore and the shoreline to find spots.
As for staying out late. February 1st I dove from 9pm to 3am and got a limit of bugs, but if I do that I've got to have nothing planned the next day and the conditions have to be perfect.