See how I go at answering them . Has the war with Britain started yet ?
They wont engage if its a friendly . Click on the WO and then click on man the deck gun . Click on the officer panel on the bottom of the GUI (right hand officer) . Click on deck gun and then click on fire at will . Sometimes if the sub is still surfacing or if the waves are big then the fire at will will return to the hold fire position . Press the space bar to begin firing again afaik . If there are enemy in range they will start firing . If its too choppy or you are too far away from the enemy then expect missed shots . I modded it that way to get the tonnage down a bit .
I don't know why the stadimeter doesn't work . Something I will have to look at .
Regarding the torpedo solution . This is new to me also as the mod Large Optics for TDW UI is a brand new mod . Read the thread for the mod about how to find a solution using the optics .
http://www.subsim.com/radioroom/showthread.php?t=209462
Use automation to do a search . The button is on the right hand side of the GUI . You must go below decks at least once before using the teleport btw .