Speed - engine - WTF?

[Grayson02sept1980]

I went to patrol a grid next to freetown in my VIIc which normal makes 10kts for traveling but only made 6

then I attacked a convoy... really patient and really well planned!

found it - went ahead it till night fell and sneaked in.... everything perfect.

I was just about to pick my targets and calculate the whole stuff when suddenly I see the smaller freighters turn... wacky... totally chaos.

then the big ones follow... I was then facing one of the flank escorts.. no problem... it was night... sea was rather rough... WTF? "UNDER FIRE" ... they saw my periscope... so I picked two med freighters and shot them... all hits... I also shot that darn Black swan before it gets me.

so I spend 4 torps on 3 targets sinking only two as the Liberty Freighter made his way... then I escaped... never was hit.

But to get to the point:
First all the time the convoys is on course.. and just when I want to say "fire tupe one" they start to turn from a course SE to a Course NNE ... wtf?

Then I realize I can only do 60% - 75% of the speed my boat should do!
The VIIc can make 7kts dived easily... it made just 4

I understand that rough weather can cut down the speed... but dived? WTF v2.0!!!

Well that was the worst patrol... I made my way away and tracked the Liberty which was slowing down yet not sinking. finished it off later... was out of fuel and went back heading north reaching the Canary Isles with my last drop of Diesel

Not funny!

Was that the rough sea? or SH3 Commander? I have malfunctions set to 1 but not sabotage and I guess I should see when one of the engines is damaged, no?

Well I'll see what's up now after I start off the Canarys... and how my boat works then. If this is a permanent problem I can get a IX as well...