Improved Combination with Floating Bodies, of Fins Adapted to Effect their Propulsion.
Year: 1895

page_text: Date of Application, 1st Aug., 1895
Complete Specification Left, 30th Apr., 1896-Accepted, 18th July, 1896
PROVISIONAL SPECIFICATION.
Improved Combination with Floating Bodies, of Fins Adapted to
Effect their Propulsion.
I, HERMANN LINDEN, of the Zoological Station, Naples, in the Kingdom of
Italy, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved combination with floating bodies, of fins
adapted to effect their propulsion; and consists in making such fins of flexible
plates, the flexibility of the latter being due to a diminution in thickness, in the
direction from the line of fixation of the fin to the floating body, to the rear or to
all the outer edges of the fin; or to a substitution of a material naturally more
flexible, in the same direction or directions. The fin in question is a flat plate
projecting aft from the stern of the floating body. It is either made fast thereto,
or pivotted thereon rudder-wise.
The present invention does not limit me in respect of any material particular
for the improved fin.
The plates may be multiple and the diminishing rigidity secured by decreasing
the length of them towards the external sides of the fin.
The fin is held to the stern of the floating body in any suitable way. It may be
held in slotted arms projecting aft from the stern; the arms being, preferably,
tapered in the same direction.
The fin may occupy a vertical, a horizontal, or an oblique position. It is actuated
by the undulatory motion of the waves or by the roll of the floating body, or by
both, according to the circumstances of the case.
Dated this 1st day of August 1895.
PHILLIPS & LEIGH,
Agents for the Applicant.
Improved Combination with Floating Bodies, of Fins Adapted to
Effect their Propulsion.
I, HERMANN LINDEN, of the Zoological Station, Naples, in the Kingdom of
Italy, Naturalist, do hereby declare the nature of this invention and the manner
in which the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
My invention relates to an improved combination with floating bodies, of fins
adapted to effect their propulsion; and consists in making such fins of flexible
plates, the flexibility of the latter being due to a diminution in thickness, in the
direction from the line of fixation of the fin to the floating body, to the rear or to
all the outer edges of the fin, or to a substitution of a material naturally more flexible,
in the same direction or directions. The fin in question is a flat plate projecting
alt from the stern of the floating body. It is either made fast thereto, or pivotted
thereon rudder-wise.

page_text: In the case of small vessels which are propelled by means of flexible fins placed
in the water so as to be moved up and down by the action of the waves, it has
been shown that it is advantageous to construct the said fins, with a view to
increase the flexibility, not as heretofore of a plate equally rigid throughout, but in
such a way that the resistance to flexure decreases from the point of fixation to the
boat, outwards towards the free edges of the fin or decreases gradually in the direction
of the back edge of the fin.
The rear free edge is represented as being the most flexible part of the fin.
The accompanying figures illustrate different examples of my improved fin.
The mode of fastening the plate A to a vessel, is shewn in Figures 1 and 2.
The former is a side elevation and the latter, a plan of a boat with a plate attached.
A is the plate which can be immoveably fixed to the boat but is generally attached
so as to be moved to port or starboard for steering purposes.
The floating body need not be a boat for carrying persons or cargo. It may be
a plaything, such as a toy duck, fish, or the like.
Further, the plates are not necessarily placed in the horizontal position. they are
shewn in Figures 1 and 2 as occupying. They may be placed in a vertical position,
in which case the rolling movement only of the vessel can be used for its propulsion.
Further, the plates may be so fixed that they may be brought into any desired
position, for example into an oblique one, in which position they will steer by
making the water streaming upwards veer to one side as well as astern.
Figure 3 shows an example of the plate in question. a is the arm to which it is
fixed. As shewn in the figure, the plate forms a slender wedge the head of which
is near a.
Figure 4 is a longitudinal section of a similar construction.
The free end of the
plate is made extra flexible, whereby the rowing effect is increased.
Figure 5 is a section of a plate built up of thin metal plates. In this con-
struction, the longest plate may be made very flexible, its sternwards projection
producing the flexible strip b.
Figure 6 is also a section of a plate in which the flexible strip is rivetted to the
main piece A of the plate. This main piece may be wedge shaped or may be of
equal thickness throughout. In the latter case it is fixed in slotted bars c, c, which
are tapered sternwards. To regulate the flexibility of the plate, the plate A can
be made interchangeable with another of a different gauge.
Figure 7 is a plan of a further modification according to which the plate consists
of a plate or sheet A made fast by one side and two end edges to a twice bent
bar d, d. The said plate A may be either of equal thickness, or tapered sternwards
as already described with reference to Figures 3 and 6. When the plate A is of
the same thickness throughout, the bent arms of the bar are so made that they
decrease in thickness and rigidity steruwards. Thus, the plate A may be of flexible
material such as india rubber, sail cloth or the like, which may be bent to the bar
in the same way as a sail to a spar or yard.
Figure 8 is a plan corresponding with Figure 4. The trapezoidal outline
illustrated may be replaced by any other.
Figure 9 is a plan corresponding with Figure 5.
Figure 10 is a plan corresponding with Figure 6.
As the invention consists in the gradually diminished rigidity sternwards, it does
not limit me in respect of the shape of the plate.
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 combination with a floating body of a plate acted upon by the undulatory
motion of the sea or the rolling of the body, the maximum resistance of the said
plate to flexure being in or near the line of its fixation to the said body and gradually
diminishing from that line towards the stern edge.
2. A modification of the combination claimed in Claim 1 according to which the

page_text: diminution in resistance to flexure is towards both top and bottom or towards both
side edges as well as to the stern edge.
3. A modification of the combination claimed in Claim 1 according to which the
plate consists of thin plates of the same or of different materials.
4. A modification of the combination claimed in Claim 1 according to which the
plate is held in slotted bars tapered so as to decrease in respect of their rigidity in
the direction of their outer ends.
5. A modification of the combination claimed in Claim 1, according to which the
plate is held in dovetails which taper from the line of fixation outwards.
6. A modification of the combination claimed in Claim 1 according to which the
three free edges of the plate are either extra flexible or consist of extra flexible
material.
Dated this 20th Jan
PHILLIPS & LEIGH,
No. 22 Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.