Logic Masters Deutschland e.V.

Draw some islands so that each island contains exactly one number (telling the size of the island) and each number is part of an island, as in Nurikabe. The islands must consist of orthogonally connected cells and may not touch other islands orthogonally. Note that unlike in Nurikabe, a 2x2-area may be fully water and not all water cells have to be orthogonally connected.

For each merchant ship (white ships), draw a path through the midpoints of some water cells from the ship to a harbour (cells with numbers) so that every harbour is entered by at least one ship. The ships can’t move diagonally, and their paths may not touch each other or themselves. Every water cell not seen by pirates (black ships) must be visited by some ship exactly once (the cells seen by pirates must not be visited). Pirates see in all orthogonal directions, but not through islands. The pirates may not see the cells marked with merchant ships.

The ships can’t turn in cells marked with a thunderstorm, whereas they must turn in cells with a whirlwind. Note that not all thunderstorms and whirlwinds are necessarily visited, as they might be in island cells or cells seen by pirates.

Two small examples:

The main puzzle:

Solve online (gray triangles are whirlwinds and rhombuses thunderstorms): penpa+ link