I have worked on commercial charter boats, and I would listen to both the captains and the mates, but I would think in an actual war situation, his fellow captains would have a better idea of, and more contact with him than his subordinates on the boat.
His Commanding Officers, and fellow Swift boat captains, with the exception of one of 19, ether won't/can't state and opinion(6) or do not think he is suitable for command(12).
Those are his peers, not the enlisted on his boat.