As a relatively experienced scuba diver I can say that the theory is correct. I haven't done an emergency ascent, as you describe, but standard practice is that

As a relatively experienced scuba diver I can say that the theory is correct. I haven't done an emergency ascent, as you describe, but standard practice is that you exhale on the whole way up or you will burst your lungs. Look at this table [1]: lung volume, depth m (ft) 2, 30m (99 ft) 3, 20m (66 ft) 4, 10m (33 ft) 8, 0 m (surface) So by ascending from 30 meters to the surface you expand the volume of the air in your lungs four times. (Of course, you don't want to do this, as you will most likely get decompression sickness, aka the bends.) [1] http://www.lakesidepress.com/pulmonary/books/scuba/sectionf.htm http://www.lakesidepress.com/pulmonary/books/scuba/sectionf....