[jazman]

I was nursing my fuel usage in an S-class tub, starting near the top of Luzon. I found that after I dived, during the recharge cycle my projected range was terrible. I'm not so sure that running on batteries saves you any fuel. From a conservation of energy view, how could it? Running submerged has go to take more energy than running on the surface. That's energy out of the batteries, that doesn't just magically reappear out of nothing.