Kitchen's 1914 British Patent #869,051 ( USA patent #1,186,210) described a clever mechanism consisting of two clamshell like deflectors that encircled a boat's propeller. These can be opened or closed in unison. When closed, all of the propeller stream is reversed and then acts in a forward direction causing the boat to move backwards. The engine usually operates at one speed, always in forward rotation. Although this reversing capability was the main objective of the invention, it is soon discovered that a boat fitted with a Kitchen Rudder can be maneuvered even better compared to boats with twin screws
Clamshells are opened and closed by a tiller-mounted mechanism. The Coxswain rotates a crank that turns a screw. The screw operates a linkage that rotates two concentric shafts. The shafts open and close two clamshells.

One hand usually the left moves the tiller from side to side for Port / Starboard steering.
At the same time, the other hand rotates the crank at the end of the tiller to change
forward / backward direction and to adjust speed. All of this occurs with the engine operating under load, constant speed, and forward rotation.

This is a harmonious relationship of mind and hand function, opposite to the discordant relationship typical of conventional boats. However it is not a natural process, rather it requires practice to be able to manipulate the mechanism in a subjective manner without requiring an awareness of a specific action that will result in a specific result. This is very similar to the process of learning a new sport such as skiing, tennis, sailing. During the learning process individual actions are identified and practiced but it is only when these separate actions are accomplished as one natural mind/ body connection that a level of competence is attained.

At "1" clamshells are open so that vessel can move at maximum speed forward.

At
"2" clamshells are full open, turned to Port which deflects propeller stream This acts to push the stern to Starboard. Thus the vessel will respond to the helm and turn to Port at full speed forward.

At
"3" clamshells are closed. The full thrust from the propeller is deflected outward and forward. This is the position for moving in reverse. If closed when moving at full speed forward, the vessel stops abruptly in less distance than with conventional reverse gearing.

At
"4" clamshells are partially closed, part of the propeller thrust is deflected forward, part directed backwards. When the two are balanced, the vessel is stationary. If the backwards thrust is greater, the vessel proceeds forward at slow speed.

At
"5" clamshells are closed and turned so that most of the propeller thrust is directed laterally toward the starboard side. This acts as a stern thruster. The vessel swivels rapidly clockwise on its center axis.



Kitchen Reversing Rudder

Inventor - John George Aulsebrook Kitchen of Lancaster, England

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Gertrude a "go slow boat" is powered by a single cylinder 3HP
St Lawrence two-cycle marine engine without transmission. Owner designed/built Kitchen Rudder provides neutral, reverse and stern thrust.
goslowboat@gmail.com
Gertrude and her Kitchen Rudder featured in Woodenboat Magazine number 185, July/August 2005, pages 86 -89