Translation:If you doubt that the captain is right, tell him!
I have translated «yIja'» as «tell it». Is this wrong? It looks an acceptable translation to me but i am not sure if ja' object is the thing reported or the person you report to.
Hard to say for certain. I don't think we have clear guidance on what proper direct objects of ja' would be. It seems reasonable that one possability might be that the thing being told is the direct object and the person being told is the indirect object. I have added "it" as an accepted translation.