Does having the scopes fully extended affect UBoat performance?

[Paul Riley]

One question I have always asked myself ever since I got serious about SH3 was "does having the scopes fully extended impede UBoat performance at all?" Example,I am ploughing through a 15/mps storm,waves are spilling right over the top,its pissing it down and there is a medium fog (what do you expect,I am in the North Sea )and I am chasing a previous sound contact.Now these are not optimal conditions for even considering such an attack never mind actually carrying it out,but I am quite an aggressive player and like to attack in all conditions and adapt the attack accordingly.In this particular scenario the PS is fully raised allowing me to keep my eyes fixed in front of me all the time,so as not to miss the moment the target appears as the UBoat dips beneath the surface momentarily.Does this negatively affect performance in ANY way by creating a 'drag' effect,thus slowing me down?
I have watched my speed for about 30 mins now and cant seem to detect any obvious change other than the sea current slowing me down 1-2 kts.
If it DOES affect performance would the same hold true for submerged operations?.
For the record,I will shadow the contact until nightfall and attack surfaced from a range of approx 2-3km (if the storm doesnt clear that is)

I remember reading about real UBoats in such conditions and I think it did affect performance somewhat,and I know they used to fully lower the scopes before submerging,to prevent the off chance they broke off from the force of submerging at speed.

Thanks.