"Smart-Filling" Obvious Water Squares

A lot has happened since finalizing square (H,3)! Besides displaying a finalized wildcard segment in (H,3), Fathom It! has automatically filled in many squares that were obviously water.

· Column 3 has a tally of one. With (H,3) a ship segment, the rest of the column must be water.

· Column 6 has a tally of zero, so all squares in the column must be water.

· Column 10 has a tally of two. Given the two hints in column 10, the remaining squares must be water.

· Row C has a tally of one. The starting hint of a submarine in (C,10) accounts for the tally, so the remaining nine squares are all water. The same is true for row E.

· Row D has a tally of zero, so all squares in the row are water.

· Because ships cannot be adjacent to each other, the squares around the left segment and wildcard along row H must be water. Similarly, the squares around the submarines in column 10 have been filled in as water.

By "smart filling" obvious water squares, Fathom It! removes much of the drudgery of board solving, allowing you to concentrate on the puzzle aspects of the board.

Identifying More Squares

Column 1 has a tally of four. Since there are exactly four unknown squares remaining, they must all be ship segments. Toggle the unknown squares in column 1:

and finalize the squares. The board should now look like: