Count the Line

Expert Used by Smart Hint

Work out every combination of ships that could make this line's number — the ones they all share are ship, the ones none of them use are water.

Ship segment
Cells that establish the pattern
Where the conclusion lands

How it works

This row still needs 3 ship cells, and just two ships are left in the whole fleet: one 2-ship and one submarine.
Both have to fit in this row without touching each other. There are only two ways that works: the 2-ship on the left with the submarine at the right end, or the submarine at the left end with the 2-ship on the right.
Both ends are ship either way — only the middle two cells are still in question.