[Capt. Morgan]

Hello and welcome.

I assume you are playing the stock game?

Two possibilities come to mind.
First, while there's no mutiny in SH-IV, there is exhaustion. If you forget to take your crew off of battle-stations they will eventually cease to function. If that's the case, just end battle stations and hope the IJN doesn't find you before your crew have caught up on their sleep.

Another possibility is running out of fuel. Steaming at Flank speed greatly reduces your mileage, and recharging your batteries also uses a lot of fuel. I believe you're out of luck if that happens.

If neither is the case, I'm sure other more knowledgeable people will be by.