USEFUL HINTS RE SCREW STEAMERS.

South Canterbury Times, Issue 2807, 23 March 1882, Page 2

USEFUL HINTS RE SCREW STEAMERS.

In reversing the screw of a steam vessel it is found (o be an invariable rule that during the interval in which a ship is stopping herself by her reversed screw the rudder produces none of its usualeffects to turn the ship, but that such effect as it does'produce is to turn the ship in the reverse direction to that in which it would turn if the screw were driving ahead. The. magnitude of this reverse effect is' always comparatively feeble, and is very different for different ships and differentconditions of loading, so that the rudder had better be on shore for all the good it does when the screw is reversed to , stop the ship. And besides .this during the interval of stopping, the ship is at the mercy of any other influence other than that of her rudder, which no longer controls her. Thus the wind,. which always tends to cause tire forward end of the ship to turn up into the wind, may, when the screw is reversed, become and cause the ship to turn it may be, in the very opposite direction to that which is desired. ' Also the reversed screw will exercise an influence which increases as the way is diminished to turn the ship to starboard or port, according as the screw is right or left handed. This is particularly the case with ships of light draught. These several influences—the reversed action of .the rudder, the effect of the wind, and the action.of the screw-pdetermine fhe course of the ship during the interval of stopping. Sometimes, they balance each other, then the ship goes straight bn ; but any’ one of the three may predominate and determine the : course of the ship. •