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| | Screw Propellers |
 | | In the course of the two succeeding years, she was tried with a great many different screws, and numerous experiments were made to discover the length, diameter, pitch, and number of blades of the screw, most effective in all the various conditions of wind and sea. |
 | | A screw of two blades, each equal to one-sixth part of a convolution, and of a uniform pitch, was, on the whole, found to be the most efficient, and this was the screw adopted in most of the ships of all classes in the British navy. |
 | | This effect is greatly increased when the clearance given to the screw in the dead-wood is too small; for the reduction of the hydrostatic pressure at the stern-post, and the increase of it at the rudder-post, on each passage of the blades, must be followed by concussion. |
| www.globalsecurity.org /military/systems/ship/steam4.htm (4080 words) |
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