Tugboats

Expert Tugboats harbors

Expert harbors take twenty-two moves or more, up to forty, in harbors so packed that nearly every barge has to move, many of them back and forth, around a rock or two.

Practice gives you harbors you haven't solved yet, as many as you like, and keeps your best time without hints. Every harbor is made and checked by a computer, and its par is the fewest moves that get the tugboat out.

How to play Tugboats

1. The harbor is crowded with barges, and the red tugboat has to get out through the gap in the harbor wall.
2. Every boat only moves forward and back along its length, never sideways. Drag a boat to slide it, as far as the water is clear.
3. Clear a way, then sail the tugboat out through the gap.

A move is one slide of one boat, however far it goes. Every harbor has a par, the fewest moves that get the tugboat out, worked out by a computer; your result shows your moves beside it. You can also tap a boat to pick it up, then tap where it should go. On a keyboard, tab to a boat and slide it with the arrow keys, holding Shift to slide it as far as it goes. Undo has no limit, and Ctrl+Z takes a move back.

Solving tips

• Work backwards from the gap. Look at what's in the tugboat's row, then at what's stopping each of those barges from moving out of the way.
• Long barges are the real problem. A barge three cells long needs a lot of clear water to get out of a row, so make room for those first.
• Sometimes the way out starts by going the wrong way. The tugboat, or a barge, may have to back up to let something else through.
• Stuck? A hint shows the next move of a shortest way out. Every move can be undone by sliding back, so you can never get stuck for good.