In “Armour Value and Damage”, insert the following paragraph immediately after the paragraph that includes the phrase, “a Vessel is in the same square as a Shot”:

For purposes of the previous paragraph, a Vessel and a Shot are considered to be in the same square if that Shot is in a square in that Vessel’s Hit Zone. The Hit Zone of a Battleship consists of the square its on, the square just in front of it, and the square just behind it. The Hit Zone of a Submarine or of a Minelayer consists of the square its on and the square just behind it. (If any of these squares would be off the Chart, or otherwise don’t exist, the Hit Zone doesn’t include them.)

In the same rule as above, change the default Armour Value of Battleships to 3, of Submarines to 2, and of Minelayers, if “Boom!” has been enacted, to 2.

Then, for balancing, change “2” to “1” in “A Mine Placed by a Minelayer decreases the Armour value of Vessels that Cruise over it by 2, and then removes the Mine.”