Improvements in Screw Propellers.
Year: 1895

page_text: Date of Application, 22nd Aug., 1895-Accepted, 28th Sept., 1895
Improvements in Screw Propellers.
I, ALEXANDER VOGELSANG, of 3, Bollwerk, Stettin, in the German Empire,
Engineer, 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 :-
This invention relates to improvements in ships' screw propellers.
According to my invention I form each blade at the root with a single part
or surface which branches into two or more parts or surfaces towards the periphery
in such a manner that the said parts lie in different planes along the axis of the
propeller..
The object of this arrangement is to cause the blades at the circumference to
force away the water in a direction nearly opposite to the direction in which
the ship is moving, whereby the pressure for causing the ship to move forward
is increased, instead of imparting a high velocity of rotation to the water as in
ordinary propellers.
The blades may be made of any suitable material and they may be attached to
the boss or propeller shaft in any suitable manner. The number of the blades can
be varied as desired and they may be arranged in similar or different planes along
the axis of the propeller. I prefer to make the pitch of the screw vary peripherally
and radially but it can also be arranged in any other suitable manner whilst the
blades can be made adjustable if desired.
In the accompanying drawing,
Figure 1 is an end view of a left handed screw propeller made according to my
invention, and having three separate blades or surfaces lying along the axis at the
root each branching towards the periphery into two surfaces or parts making six
surfaces in all.
In Figure 2 a is the projection of one of the above blades and the circum-
ferential limit of the path of the same: b is a side view of the blade and can end
view of the same: d shews the angle at which the blade enters the water when the
propeller is revolving in the direction of the arrow and the ship is moving in the
direction of the arrow f, and e shews the angle at which the same leaves the water.
In this arrangement the blades act similarly for both the forward and backward
motion of the ship, the edges d and e exchanging their functions.
Figure 3 represents a two bladed right handed screw propeller adapted for
torpedo boats.
Figure 4 shews a four bladed propeller adapted for heavy slow going freight
ships, tugs and river boats in which the propeller is only partially immersed.
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. In a screw propeller forming the blades with a single surface or part at the
root and with two or more surfaces or parts towards the periphery, the said surfaces
Iving in different planes, as hereinbefore described.

page_text: 2. The improved screw propellers hereinbefore described and illustrated in the
accompanying drawing.
Dated the 22nd day of August 1895.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.