The bubbles thing was taught as it was easy to visualise. Before computers it could be very difficult to gauge how fast you were ascending especially without visual reference ie. a blue water ascent.
Different agencies had different ascent rates- some were really slow, some extremely fast. Haldane had specific theories on tension ratios of Nitrogen which one could never exceed but also thought it was optimal to ascend at the fastest possible without breaking the ratio, resulting in rapid ascents from 200' to 100' and then slowing it down from there.
When the great minds of the agencies got together to hash it out, everyone had a different opinion- nobody was backing down so they took the average which was 60ft/min. Still very very fast. Doppler tests have since shown that a 30'/min ascent rate is optimal from most recreational depths.
No faster than the smallest bubbles is still taught and is the only meaningful way to judge ascent rates without computers for the vast majority of divers.
Different agencies had different ascent rates- some were really slow, some extremely fast. Haldane had specific theories on tension ratios of Nitrogen which one could never exceed but also thought it was optimal to ascend at the fastest possible without breaking the ratio, resulting in rapid ascents from 200' to 100' and then slowing it down from there.
When the great minds of the agencies got together to hash it out, everyone had a different opinion- nobody was backing down so they took the average which was 60ft/min. Still very very fast. Doppler tests have since shown that a 30'/min ascent rate is optimal from most recreational depths.
No faster than the smallest bubbles is still taught and is the only meaningful way to judge ascent rates without computers for the vast majority of divers.