Engine running mode and deckgun operation

[joho]

Is there a way to change from diesel to electric runningmode while on the surface.
Lets say my diesel is damaged or I wish to extend my range can I switch to the electric engine manually some how?

Then I am having problem with the deckguncrew they, sometimes, wont open fire.
I give all the orders, I mark the target via UZO and Binoculars. Nothing, not a thing happens. It is not until I take control and fire the gun personally that the crew gets the idea.

Any thoughts out there?