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
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.
Gertrude and her Kitchen Rudder featured in Woodenboat Magazine number 185, July/August 2005, pages 86 -89