Author: Vladimir Portugalov
Place boats into some cells. Cells with boats can not share a point with each other and with numbered cells. Numbers are lighthouses which show how many boats are illuminated by the lighthouse. Each lighthouse illuminates all boats in the same row or the same column.
Grid control: Click the mouse button at the selected cell to set/remove a boat. Second click will put auxiliary cross sign, which doesn't affect correctness of the solution, but helps visually. You can also drag the content of one cell to another with the mouse. More details about grid control are at the help page.