Improvements in or connected with Rudders.
Year: 1896

page_text: Date of Application, 8th Feb., 1896
Laminate Crocification loft 0th Nov 1806 Accented 9th lon
1807
Improvements in or connected with Rudders.
I, JOHN ABERNETHY COGHILL, of 3 Dorset Street, Southampton, in the
County of Hampshire, Passenger Agent, do hereby declare the nature of this
invention to be as follows:-
My invention relates to improvements in and or connected with rudders by
means of which certain advantages are obtained.
As usually constructed a rudder consists of a stem with a blade or feather
extending on one side of its geometric axis. A drawback to this form of rudder
is that the strain taken up by the blade or 'feather coming upon one side of the
stem tends to break it. The object of my invention is to obviate or diminish the
said tendency to breakage and for this purpose instead of having a single blade or
feather on one side of the said geometric axis I make my rudder of such form that
it consists of a central stem, turning in suitable bearings, with two. blades or
feathers at diametrically opposite sides of the axis of the stem with the view of
having the strain taken up by one blade or feather neutralized or compensated for
by the strain thrown upon the other blade or feather. The two blades or feathers
When
thus balance one another on the two sides of the geometric axis of the stem.
placed in position the rudder turns pivotally on the lower horizontal of the rudder
frame whilst the stem passes up through the counter as is usual.
On each side (preferably fore and aft) of the rudder and at a distance apart
slightly greater than the width of said rudder are two shafts hereinafter termed
the auxiliary shafts lying parallel with the rudder stem. These auxiliary shafts
also turu pivotally on the lower horizontal of the rudder frame and pass upwards
through the counter. At the extremities or at one or more points intermediate
between the extremities of the auxiliary shafts, and in corresponding planes I cut
or mount cogs or cog wheels: and in the same plane I mount fast upon the rudder
annular cog wheels, the cogs borne by the rudder engaging with the cogs borne by
the auxiliary shafts. In the stern of the vessel a cog wheel is concentrically
mounted upon the stem and the cogs of which engage with cogs cut or mounted
upon the auxiliary shafts. These auxiliary shafts may be angularly rotated by
steering gear of any desired construction.
The operation of my invention is as follows: Let us assume that the rudder is
in its normal position, that is to say in the position which it occupies when the
vessel to which it is attached is travelling in a right line. Let us assume now that
it is desired to actuate the rudder so as to turn the vessel in one direction or in
another. To do this the two auxiliary shafts are angularly moved in opposite
directions the effect of which is, through the engagement of the cogs as aforesaid,
to angularly move the rudder so that the latter will now occupy a vertical plane
It will then be seen that
cutting the vertical longitudinal plane of the ship.
whereas one of the blades or feathers of my rudder will extend in one direction the
other blade or feather will extend in the other direction. That is to say if the
after blade or feather is put to starboard the fore blade will extend to port or
vice versa.
I have hereinbefore spoken of the auxiliary shafts as actuating the rudder. I
however also contemplate the case wherein the rudder stem, or cog-wheel mounted

page_text: Or the
thereon, is operated by steering gear so that the auxiliary shafts then serve not as
actuating devices but as steadiers and strain-takers for the rudder.
auxiliary shafts may combine both functions.
I contemplate placing the rudder in a frame of rectangular or approximately
rectangular shape situated forward of the stern post.
Having now briefly described the nature of my invention with reference to a
contemplated construction thereof, I desire it to be understood that I do not limit
myself to the structural details herein before set forth, as, the principle of my
invention being understood, persons skilled in the art to which it appertains will be
able to modify the details to an indefinite extent.
Dated this 8th day of February 1996
J. G. LORRAIN, M. Inst. E.E., M.I. Mech. E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.
1, JOHN ABERNETHY COGHILL, of 3 Dorset Street, Southampton, in the
County of Hampshire, Passenger Agent, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-.
My invention relates to improvements in or connected with rudders by means of
which certain advantages are obtained.
As usually constructed a rudder consists of a stem with a blade or feather
extending on one side of its geometric axis. A drawback to this form of rudder
is that the strain taken up by the blade or feather coming upon one side of the
stem tends to break it.
The object of my invention is to obviate or diminish the said tendency to
breakage and for this purpose instead of having a single blade or feather on one
side of the said geometric axis I make my rudder of such form that it consists of
a central stem, turning in suitable bearings, with two blades or feathers at
diametrically opposite sides of the axis of the stem with the view of having the
strain taken up by one blade or feather neutralized or compensated for by the
strain thrown upon the other blade or feather. Such a rudder is illustrated in
Figure 1 in which the two blades or feathers 1, 1 a, thus balance one another on the
two sides of the geometric axis of the stem 2. When placed in position the rudder
turns pivotally on the lower horizontal 3 of the rudder frame whilst the stem passes
up through the counter 4 as is usual.
On each side (preferably fore and aft) of the rudder and at a distance apart
slightly greater than the width of said rudder are two shafts 5, 5 a, hereinafter
termed the auxiliary shafts, lying parallel with the rudder stem. These auxiliary
shafts also turn pivotally on the lower horizontal 3 of the rudder frame and pass
upwards through the counter 4. At one or more points of the auxiliary shafts,
and in planes corresponding with one another, I cut or mount cogs or cog
wheels 6, 6 a, 66, 6c and in the same plane I mount fast upon the rudder annular
cog wheels 7, 7 a, the cogs borne by the rudder engaging with the cogs borne by
the auxiliary shafts. In the stern of the vessel a cog wheel 8 is concentrically
mounted upon the stem 2 and the cogs of which engage with the cogs 9, 9 a, cut or
mounted upon the auxiliary shafts. These auxiliary shafts may be angularly
rotated by steering gear of any desired construction.

page_text: Figure 2 is a diagrammatic plan section showing one of the annular cog wheels 7
mounted on the rudder and showing also the cog wheels on the auxiliary shafts
which gear therewith.
The operation of my invention is as follows:-
Let us assume that the rudder is in its normal position that is to say in the
position which it occupies when the vessel to which it is attached is travelling in
a right line. Let us assume now that it is desired to actuate the rudder so as to
turn the vessel in one direction or in another. To do this the two auxiliary shafts
are angularly moved in opposite directions (the same direction of rotation) the
effect of which is through the engagement of the cogs as aforesaid, to angularly
move the rudder so that the latter will now occupy a vertical plane cutting the
vertical longitudinal plane of the ship. It will then be seen that whereas one of
the blades or feathers of my rudder will extend in one direction the other blade or
feather will extend in the other direction. That is to say if the after blade or
feather is put to starboard the fore blade will extend to port or vice versa.
I have spoken of the auxiliary shafts as actuating the rudder. I however also
contemplate the case wherein the rudder stem, or cog wheel mounted thereon, is
operated by the steering gear so that the auxiliary shafts then serve not as
actuating devices but as steadiers and strain takers for the rudder.
In practice I place the rudder in a frame of rectangular or approximately
rectangular form situated forward of the stern post.
In Figure 3 I show a modified form of my invention which differs from that shown
in Figure 1 mainly in that the auxiliary shafts are housed within the frame except
at the parts where the cogs or cog wheels are situated and that the said auxiliary
shafts instead of passing downwards all the way to the lower horizontal of the
frame pass to the bearings situated but a short distance below the lowest cogs or
cog wheels. In this figure I show only one anuular cog wheel on the rudder, but
I may of course vary this according to circumstances. In some cases I may
employ only a single auxiliary shaft.
I desire it to be understood that I do not limit myself to the structural details
herein before set forth, as, the principle of my invention being understood, persons
skilled in the art to which it appertains will be able to modify the details to. an
indefinite extent.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The double bladed rudder substantially as set forth.
2. The combination of a double bladed rudder and an auxiliary shaft or shafts,
the said parts having co-operating cogs or cog wheels substantially as set forth.
Dated this 7th day of November
For the Applicant,
J. G. LORRAIN, M.I.E.E., M.I. Mech. E.,
Norfolk House, Victoria Embankment, London, W.C.,
Chartered Patent Agent.