A submarine submerges by admitting seawater \((S=1.03)\) into its ballast tanks.
The amount of water admitted is controlled by air pressure, because seawater
will cease to flow into the tank when the internal pressure (at the hull
penetration) is equal to the hydrostatic pressure at the depth of the
submarine. Consider a ballast tank, which can be modeled as a vertical half-
cylinder \((R=8 \mathrm{ft}\) \(L=20 \mathrm{ft}\) ) for which the air pressure
control valve has failed shut. The failure occurred at the beginning of a dive
from 60 ft to 1000 ft. The tank was initially filled with seawater to a depth
of \(2 \mathrm{ft}\) and the air was at a temperature of \(40^{\circ}
\mathrm{F}\). As the weight of water in the \(\operatorname{tank}\) is important
in maintaining the boat's attitude, determine the weight of water in the tank
as a function of depth during the dive. You may assume that tank internal
pressure is always in equilibrium with the ocean's hydrostatic pressure and
that the inlet pipe to the tank is at the bottom of the tank and penetrates
the hull at the "depth" of the submarine.