what's the 30*2.2

1000 feet ~ 300 m
pressure rises approx 1 atmosphere (1kg*g/sq cm) per 10 m depth (g=9.81 m/s/s)
1 kp (kg-force, kg*g) ~ 2.2 lbf
so, pressure rises approx 2.2 pounds per sqare centimeter per 10 m of depth

(I should have used furlongs somewhere, but I could not remember how much is that - 220 yards?)

Cheers!

Dragi "Bonzi" Raos
Zagreb, Croatia
Q#5196, MkII#80000376, 18GB green