HALF ASTERN TO DEAD IN THE WATER
The ship's behavior when backing can only be learned by practice and observation. The master and mates aboard must have a feel for if they are to maneuver their ship properly. While proceeding at 6 knots put the engine half astern and the rudder amidships.
You will find that the ship changes heading significantly, in some cases as much as 80 to 90 degrees in shallow water and somewhat less in deeper water, although she doesn't travel a significant distance from her original track. Despite the differences in ship behavior in shallow water as compared to deeper water, there is not much difference in the stopping distance. The ship's tendency to twist in this manner when backed directly affects her performance of certain routine maneuvers. The greater the magnitude of this twisting effect, the more effectively she can be backed and filled in an anchorage or other confined area, but the more difficult it is to stop in a narrow channel when it is necessary to keep the ship's heading within reasonable limits. Depending on the ship's configuration, and especially the location of the house and any large objects such as containers on deck or an exceptionally high freeboard, the backing and filling maneuver can be significantly distorted by the wind. If you think ahead though, this wind effect can be used advantageously when maneuvering in tight quarters. Since the ship moving forward usually wants to head up into the wind once the rudder's effectiveness is lost, and to back into the wind once sternway develops, the twisting effect that occurs when backing the engine can be used to the shiphandler's advantage: plan to back when the wind will amplify or dampen this twisting effect to your advantage.
