Interesting find.
I believe there is a RL difference between "operationally" surfaced, and surfaced with all tanks blown dry.
Operationally, I believe that some ballast tanks were kept flooded for safety reasons (call it reserve potential bouyancy), and the boat sat lower in the water, which is what we see with most photos.
With all tanks blown dry, the boat would obviously sit higher in the water, be less stable (pitch and roll), and may have better speed/efficiency characteristics as less hull in the water means less drag.
Sub experts please feel free to correct the above.
Giving the first post here, it seems this is moddeled by SH3, which is cool.
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