diff -r 51305152af09 -r 716595242a19 src/ai/api/ai_marine.hpp
--- a/src/ai/api/ai_marine.hpp	Tue Jun 17 21:44:41 2008 +0000
+++ b/src/ai/api/ai_marine.hpp	Tue Jun 17 22:37:09 2008 +0000
@@ -67,6 +67,19 @@
 	static bool IsCanalTile(TileIndex tile);
 
 	/**
+	 * Checks whether the given tiles are directly connected, i.e. whether
+	 *  a ship vehicle can travel from the center of the first tile to the
+	 *  center of the second tile.
+	 * @param tile_from The source tile.
+	 * @param tile_to The destination tile.
+	 * @pre AIMap::IsValidTile(tile_from).
+	 * @pre AIMap::IsValidTile(tile_to).
+	 * @pre 'tile_from' and 'tile_to' are directly neighbouring tiles.
+	 * @return True if and only if a ship can go from tile_from to tile_to.
+	 */
+	static bool AreWaterTilesConnected(TileIndex tile_from, TileIndex tile_to);
+
+	/**
 	 * Builds a water depot on tile.
 	 * @param tile The tile where the water depot will be build.
 	 * @param vertical If true, depot will be vertical, else horizontal.