A few dumb questions regarding sonar profile etc

[BasilY]

These are probably trivial, but I am curious anyway, so indulge me...

Will these actions effect how likely you are detected by destroyer's hydrophone/sonar? (SH3/GWX or IRL)

- Have periscopes up (but not breaking the water surface)
- Have torpedo tubes open.
- Have un-repaired external damage.
- Have a deck-gun installed (effects the VII/41)
- Issueing commands.
- Making torpedo settings. (is there a mechanical process involved IRL?)
- Assigning crew
- Requesting a sonar reading from the Sonarman
- Doing a depth check (doesn't it send out an active sound?)

Will these reduce the max diving and speed of a boat?
- Have periscopes up.
- Have torpedo tubes open.
- Have un-repaired external damage.

What's the down side of keeping torpedo tubes open in this game?

Is being near to the surface in rough seas harder for a destroyer to detect than being in medium depth, said, 50m?