I haven't skippered an S-Boat yet but, if I'm interpreting your initial post correctly, it seems that you submerge during the day and surface at night. That is not an advisable tactic. For evasive purposes alone, you can move much quicker, and change your location faster while on the surface. If you've been spotted unaware, by the enemy, prior to submerging for the day, you're essentially waiting to be found by the forces that have been dispatched to locate you. Only submerge for ambush or evasion. Don't sit and wait to be found by the enemy.
