Periscope Question

[Luno]

In the game you can look through either periscope while each is in a low position, but I wonder if that was possible in an actual u-boat.

The attack scope console seems to have been stationary, and while you sat in the bike-saddle, the whole thing rotated via electric motors. Because the console itself doesn't go up or down, it seems like it could be possible to see an image through the scope whether or not it's at the lowest or highest position.

However, the observation scope, which has a simple console in the command room, is rotated by hand with the folding grips. The console raises/lowers with the scope, as far as I can tell, and even disappears into the floor in its lowest position (this is not visually modeled in SH3).

So, should it be possible to see anything through the attack scope, or observation scope if it's at a low position? The reason I ask is because one can simply raise the scope so that it sits just above the waves, barely visible. I wonder if that's at all realistic.