nuke1 atm = 101325 Pa
So 5 atm = 506625 Pa
P = ρgh where we assume the density of water is 1000 kg/m^3 and g = 9.81 m/s^2
Substituting our values into the equation we get,
506625 = 1000*9.81*h
Rearranging the above and we come to...
h = 51.64m
Yup, that checks out