Rulebook - page 6 wrote:
The Captain draws an M (for "mine") on a space adjacent to his submarine.
The Captain cannot drop a mine in a space on his route (with a line drawn in it), and a submarine cannot move into a space with its own mine.
Can the mine be placed diagonally adjacent or only orthogonally adjacent?
I ask because movement is orthogonal only, so it seems odd that I could launch a mine further in one action than I could move the submarine. Damage seems to be the only feature to include diagonals and even then, only as part of an area of effect.
Despite all of this reasoning though, the rules as written don't expressly forbid diagonal placement.