Kedging is a method of moving a
sail powered ship through shallow water in the absence of wind. This tedious method of
propulsion involves the ship's
longboats, the entire
crew, and two
anchors.
The longboats take an anchor ahead of the ship and drop it over the side, when the anchor is on the bottom the crew on the ship grabs hold of the line and hauls it in, pulling the ship over to the anchor. Once the ship can be hauled no further, the ship's main anchor is dropped to hold it in place, the kedging anchor is pulled up and the process is repeated.
Moving even a small frigate through becalmed waters is grueling at the least. This is why kedging is only used in emergencies where the ship may be lost if it is not moved. This method of propulsion was successfully used by the crew of the USS Constitution in the War of 1812 to escape the British.