The pressure acting on a submarine is $3 \times 10^5 \mathrm{~Pa}$ at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be :
(Assume that atmospheric pressure is $1 \times 10^5 \mathrm{~Pa}$ density of water is $10^3 \mathrm{~kg} \mathrm{~m}^{-3}, \mathrm{~g}=10 \mathrm{~ms}^{-2}$ )