Improvements in Screw Propellers, Rudders, and Stern Posts for Ships or Vessels.
Year: 1897

page_text: COMPLETE SPECIFICATION.
Improvements in Screw Propellers, Rudders, and Stern Posts for
Ships or Vessels.
I, ALBERT VIERT, of 110 Fullerton Avenue, in the City of Chicago, State of Illinois,
United States of America, Manufacturer, 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 a novel construction in a propeller, the object being to
provide a device of this kind which will act upon the water with the greatest power
compared to its size, and consists in the features of construction and combinations of
parts hereinafter fully described and claimed.
One feature of my invention consists in so forming the hub of my propeller that the
portions thereof which require to be of greatest strength project beyond the weaker
portions in such a manner as to produce spiral shoulders which are adapted to act as
propellers while the ship is being propelled forward, and in the conical shape of said
hub whereby its resistance in passing through the water is greatly diminished.
Another feature of my invention consists in the shape of the blades whereby a large
amount of water is caught thereby at their forward ends or points at which it may be
said, they first engage the water.
Another feature of my invention cousists in bending the blades so that at the point
where they first engage the water their angle of inclination to the plane of revolution
is very small and gradually increases to a spiral curve of about forty-five degrees to the
longitudinal axis of the hub.
Another feature of my invention consists in bending the blades so that at the points
at which they first engage the water their planes extend at an angle of about live
degrees forward of the perpendicular radii of the hub and gradually incline rearwardly
therefrom so that their rear ends extend at an angle of about forty-five degrees
rearwardly of said perpendicular radii of said hub.
In the accompanying drawings illustrating my invention:
Figure 1 is a side elevation of the stern end of a vessel provided with my propeller
and showing the latter in side elevation. Fig. 2 is a side elevation of my propeller
looking at same when turned about forty degrees from the position shown in Figs.
aud 3 in the direction of the arrow shown in Fig. 3. Fig. 3 is a perspective view of
my propeller. Fig. 4 is a rear elevation of my propeller. Fig. 5 is a section of the
same on the line 5-5 of Fig. 4. Fig. 6 is a sectional view of the hub on the line 6—6
of Fig. 4. Fig. 7 is a sectional view on the line 7-7 of Fig. 1. Fig. 8 is a perspective
rear elevation of a propeller constructed in accordance with my invention provided
with three blades.
Referring now to said drawings, A indicates the hub of my propeller which is
preferably hollowed out as at 1. Said hub is of conical form having its greatest
diameter at its rear end and is reduced at its forward end. The blades B are spirally
mounted upon said hub, being cast integral therewith, and immediately rearward of

page_text: and parallel with the lines of juncture between said hub and said blades, said bub is
cut away so as to form spiral shoulders facing the rear end of said hub, which obviously
provide additional propelling surface without weakening the hub.
As shown in Fig. 6 the forward end of the hub (as shown by the lines x and y)
gradually increases in diameter toward the blades, while immediately to the rear
thereof it appears to decrease in diameter. This, however, is not the case but appears
to be so, for the reason that said portion of the hub is cut away to form the spiral
shoulders above referred to, and which give the rear end of said hub the form of a
double eccentric or cam as shown in Fig. 4, in which the line indicates the
forward corner of the hub and the corners & the points of greatest diameter at the rear
end of the hub. In Fig. 5 I have shown another sectional view of the hub in which
it will be p'ainly seen that the hub is of greatest radius at the point & and that at the
point the radius decreases. Suid shoulders are, however, cut down to a greater
extent than the difference between the radial distances of the points & and so that
the smallest diameter of the rear end of the hub is smaller than the diameter of the
forward end. This in Fig. 5 makes the hub appear to have the shape of a portion of a
cone whose base is adjacent the forward end of the hub, and very slightly reduced
forward of the same.
By means of my manner of forming the hub I am enabled to make the same very
short and thus save considerable space and weight without decreasing its strength.
The said blades B3, when only two in number, are mounted upon said hub
diametrically opposite each other and extend spirally around the same at an angle of
about forty-live degrees to the longitudinal axis thereof. The planes of said blades
extend at varying angles to the perpendicular radii of said hub at consecutive points
from their forward to their rear ends, said variations being always in one direction.
At their forward ends 2 it will be seen that said blades incline at an angle of about
five degrees to the perpendicular radii of said hub forward thereof. From this point
the inclination is gradually rearward so that at about the points 3 the said blades are
perpendicular to the longitudinal axis of the hub, at the points 4 the inclination is
about ten degrees rearward, at the points 5 twenty degrees rearward and so on in
regular gradation to the rear ends 6 where the inclination is about forty-five degrees.
The outermost edges of said blades B lie in what may be termed a "cylindrical
plane," that is to say in the periphery of an imaginary cylinder as shown in Fig. 4,
but owing to the gradually increasing inclination of said blades to the perpendicular
radii of said hub from their forward to their rear edges, said outermost edges follow
said "cylindrical plane" in a spiral curve whose angle of inclination to the longitudinal
axis of the cylinder (which coincides with the longitudinal axis of the hub) gradually
decreases, that is, at their rear ends said blades follow said cylinder in a spiral curve
at an angle of about forty-five degrees to such longitudinal axis and this angle
gradually decreases to about thirty degrees at the rear ends of said blades. Thus
while said blades appear to be of equal radial extent from their front to their rear
ends, they actually increase, such increase representing the difference in length
between a perpendicular radius of the cylinder and a radius extending at an angle of
forty-five degrees to the longitudinal axis of the hub. To make this clear it might
be well to state that the difference in radial extent between the forward and rear ends
of the blades is equal to one-half the difference between the diameter and diagonal of
a square.
I do not wish to be limited to the exact extent of the rearward inclination
of the blades to the perpendicular radii of the hub as I contemplate varying this angle
as in practice I may find most advantageous. As far as I am at present advised,
however, I do not believe that said inclination will be other than thirty to forty-five
degrees.
From the above description it will be seen that the blades B gradually increase in
area from their forward to their rear end portions so that they present a greater
surface to the water at their rear end portions than at their forward end portions. This
tends to force the water inwardly and overcome the centrifugal force applied to the
water during its contact with said propeller or during the time that the body thereof
is acted upon. Thus I overcome the detrimental centrifugal force and in consequence

page_text: my propeller throws the water to the rear in a cylindrical columu laving a diameter
equal to the diameter of said propeller.
In Fig. 8, I have shown a perspective rear elevation of a propeller constructed in
accordance with my invention provided with three blades. I have found in practice
that it is best to increase the number of blades in accordance with the diameter of my
propelloras in very large sizes the strain upon two blades is very great. I contemplate
increasing the uuinber still further for maximum sizes without departing from the
spirit of my invention.
In Figs. 1 and 7 I have illustrated a rudder which is particularly adapted for use in
connection with my propeller.
This rudder is constructed on the theory that the column of water thrown by the
propeller will seek to pass in the direction in which it meets with the least resistance
and, hence, will pass toward the surface as the water there is not so dense as at a
greater depth.
To this end I have constructed ny rudder so that tongue or blade 10 thereof will
lie in the path of the water column thrown by the propeller thus giving it an upward
incline. In the instance illustrated I have shown the said tongue or blade 10 mounted
upon a shaft 11 journalled in a frame 12 on the stern, such as is generally used on
ships of high tonnage. The rearmost upright or post 12 of said frame 11ª is concave
to receive said shaft 11 and give the same further support. Said upright or post 12*
is provided with a forwardly extending triangular projection 13 having sharp outer
edges, the apex of which is preferably about in alignment with the uppermost
portion of the propeller shaft. The side b of said projection 13 practically forms a
continuation of the edge c of said blade 10. Said projection 13 serves to divide the
water column and throw one half on cach side of said rudder so as to ensure equal
pressure on each side thereof. Said projection 13 also serves to relieve the post 12"
of the full pressure of the water column.
To cause said rudder to catch the water to a greater extent I provide a series of
grooves 14 therein on each side, which gradually decrease in depth and width from the
forward to the rear end of said blade 10. In this manner the resistance offered by said
rudder is increased and it is thus acted upon with greater force.
Having now particularly described and ascertained the nature of iny said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
"
1. A propeller for vessels comprising a plurality of blades having spiral outer edges
lying in a cylindrical plane" said blades being spirally mounted upon a hub and set
at a gradually increasing incline to the perpendicular radii of said hub from the
forward to the rear end portion of said hub.
2. A propeller for vessels comprising a plurality of blades having spiral outer edges
lying in a cylindrical plane," said blades being spirally mounted upon a hub of
conical shape and provided with spiral shoulders adjacent said blades.
"
3. A propeller for vessels comprising a plurality of blades having spiral outer edges
lying in 8 cylindrical plane," and spirally mounted upon a hub, said blades gradually
increasing in extent from their forward edges to thoir rear edges, said blades being set
at a gradually increasing incline to the perpendicular radii of said hub from the forward
to the rear end portion of said liub.
4. A propeller for vessels comprising blades of spiral outline spirally mounted upon a
hub provided with spiral shoulders parallel with said blades.
5. A propeller for vessels comprising blades of spiral outline spirally mounted upon
a hub provided with spiral shoulders parallel with said blades, said blades being set
at a gradually increasing angle to perpendicular radii of said hub from the forward to
the rear end portions of said hub.
6. In a propeller, a hub having blades spirally mounted thereon, and having its
outer surface cut away to form spiral shoulders extending practically parallel with said
blades.
7. In a propeller, a hub having blades spirally mounted thereon, said hub being cut

page_text: away to form spiral shoulders thercon corresponding in number and parallel with said
blades, and facing the rear end of said hub.
8. In a propeller, a hub of conical form gradually increasing in diameter from its
front to rear end and cut spirally away to form spiral shoulders thereon facing the
rear end of said hub.
9. In a propeller, a hub of conical form gradually increasing in diameter from its
front to rear end and cut spirally away to form spiral shoulders thereon gradually
increasing in depth from the front to the rear end of said hub and facing said rear
end.
10. A rudder comprising a blade or tongue mounted upon a shaft and extending
rearwardly therefrom at an upward incline, substantially as described.
11. A rudder comprising a blade or tongue provided with longitudinal grooves or
recesses mounted upon a shaft and extending rearwardly therefrom at an upward
incline, substantially as described.
12. The combination with a rudder frame provided with a concave rearward upright
having a forwardly extending triangular projection, of a rudder mounted in said frame
and comprising a blade or tongue mounted upon a shaft and extending rearwardly
therefrom at an upward incline, the upper edge of said blade being in aligninent with
the upper edge of said projection, substantially as described.
13. The combination with a rudder frame provided with a concave rearward upright
having a forwardly extending triangular projection of a rudder mounted in said frame
and comprising a blade or tongue provided with lougitudinal grooves or recesses
mounted upon a shaft and extending rearwardly therefrom at an upward incline, the
upper edge of said blade being in alignment with the upper edge of said projection,
substantially as described.
Dated Guis 27th day of January 1091.
ALBERT VIERT.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.