Help with first Campaign mission, Akula
 

I always get "Counterdetected". What is the best strategy?
Are the subs or the surface ships best at detecting me?
Does it matter if I drive 5kts or 10kts?

Playing the Akula, and the RA mod

I think that's a known issue with that scenario where the random area that it places the two subs are too close to each other. I remember that I solved the issue by going in with the scenario editor, and simply moving the sub start points a little farther away from each other until they consistantly didn't detect each other on mission start.

Can I edit the mission so I will win right away and move on to the next?

You can alter the victory conditions.