Remember what I said about those seals.
The other end of the screw (prop) is bolted to the shaft which goes into the people tank to get turned by the reduction gears.
The shaft seals "clinch" tighter to the shaft as the pressure increases, so you also need more horsepower to overcome that friction. In other words, the deeper you go the louder you get in terms of ship-generated noise.
The one thing that has bugged me over the years, however, is the scope. Scopes rarely flood. The scope has the same rating as the hull in terms of Test Depth, it sees the same pressure as the hull and that's how it was designed.
Shessh, you'd think a 10 year old $20 game would get that right..
