People here in the forum who have actually been at sea in a war ship say that it's unrealistic. There's two things: apparently the water pressure is too much, as the glass in the periscopes would not be able to take the pressure. Another thing would have been that there are no light sources in a night sea so it would have been too dark to see anything. I guess one might not see much in daylight, either.
About your experiences: hard working nice work there
That's what we love about SH3!
On a side note: you do know that the weather in SH3 can be edited? What I personally try to achieve is continuous stepwise weather changes. The weather in GWX is too static in my mind. Might be days without a slightest weather change. Storms are ok, though. Especially late in the war the storms might keep one alive a little longer as the airplanes don't seem to fly in bad visibility - though I remember reading that NYGM has scripted in some night fliers to the Bay of Biscay