To drown Barge, it is necessary to shoot 5-7 times at it precisely from gun.
In my opinion they are very difficult for drowning or immobilized (for example, it is damaged the rowing screw).
And still, passengers do not suffer from damages put by the opponent to the barge.
Ferry through the rivers on barges very easy action now.
Even if the opponent is a lot of and precisely shoots on barges.