Glenn Ashmore wrote:

One atmosphere of pressure (14.7 psi) is 33 feet of seawater. THe .445
is correct but your math is wrong. 1.5 atmospheres would be about 50
feet.

One atm is 14.7 psia, it is a measure of absolute pressure. Itis the
pressure at the surface of the water. Pressure at 33 feet depth is 2
atmospheres absolute or 14.7 psig or guage pressure.

To obtain a pressure of 1.5 atmospheres (a measure of absolute pressure)
you would have to descend to around 16 feet. The guage pressure at that
depth is about 7 psig.

The pressure at 7 feet may be described as around 3 psig or 17.7 psia.
It is not by any measure 1.5 atm.

Rick