Hello Mr. Tore,
The best way to show my point is with a drawing...
We have two drinking glasses forced into a pool of water where both drinking glasses are partially flooded (we now have compressed air in the drinking glasses). We put two (2) glass tube in the water with my finger over the top end of each tube; one outside the drinking glass on the left, and one inside the drinking glass on the right.
Now, I allow the glass tubes to flood (this would be like opening the selector valve). The results would be that both tubes would flood up to the pool's water level. The water in the glass tubes came from the pool and there no connection or affect on the air pressure level inside either drinking glass air pressure area.
The water pool pressure acting inside both drinking glass enforces the water level in both scenario. Taking water from below the waterline in the drinking glass on the right changed nothing... With respect to the drinking glasses because the water came from the pool!
See my drawing!
When I inserted the two tubes into the pool of water, the pool's water level increased by the volume of both plugged water tubes. When I allowed the tubes to flood, then the pool water level decreased by the volume of water inside of both tubes.
Basically, when the selector valve is opened in the U-Boat, the water is coming from the sea because of the open Kingstons.
The U-Boat is not going to decrease the sea's water level when opening the selector valve and allowing the selector pipe to flood...
I hope this all makes sense???
Regards,
Don_
