Rolling two or more 1s means shot passes over and may hit another ship in the line of fire.
How it works
If a broadside roll includes two or more 1s, one damage point is inflicted on any ship, friend or foe, in the line of fire within 6 squares.
If you ever roll two or more 1s then some shot has passed over the target – inflict 1 point of damage on any ship (friend or foe!) that is in line of fire and not more than 6 squares away.