Improvements in Propelling Apparatus for Ships or Vessels.
Year: 1891

page_text: Date of Application, 3rd Oct., 1891
Complete Specification Left, 1st July, 1892-Accepted, 17th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Propelling Apparatus for Ships or Vessels.
We, JOHN ISAAC THORNYCROFT of the firm of J. I. Thornycroft & Co., of
Church Wharf, Chiswick, in the County of Middlesex, Steam Yacht and Launch
Builders, and SYDNEY WALKER BARNABY of The Hollies, Chiswick Mall,
Middlesex, Naval Architect, do hereby declare the nature of this invention to
be as follows:-
:-
In the Specifications of Letters Patent granted to one of us, viz. the said
John Isaac Thornycroft, and numbered 13:30 of 1879, and 1853 of 1881, there are
described various arrangements of propelling and steering apparatus for ships or
vessels, in which there is used a propeller having behind it and arranged in line
with its boss, a body herein called the rearward body that has a gradually
increasing diameter or width for a short distance and afterwards a gradually
diminishing diameter or width to its rearward end, and is furnished with guide
plates or blades for gradually deflecting and directing the water projected from the
propeller into a direction approximately parallel with the axis of the rearward
body, the said propeller, rearward body and guide plates or blades being surrounded
by a pipo, tube, case or hollow guide, herein called a tube.
Now this invention has for object to enable navigable vessels fitted with
propelling and steering apparatus of the kind mentioned to readily go astern when
necessary.
For this purpose there is used in conjunction with the propeller that works
within the tube, a stern way propeller or propellers the blades of which are external
to and at the forward end of the said tube. The serew blades of this stern-way
propeller, or propellers, may be carried by a boss or bosses mounted on the same
shaft as the first propeller so as to be directly in front of but separate from this
propeller. Or instead of using a separate propeller the screw blades of the first
propeller may be prolonged in a forward direction so as to extend some distance
beyond the forward end of the tube. In either case it is advantageous that the
screw blades, or the portions thereof, that are external to the tube, should be of
uniform pitch such that during the forward movement of the vessel by the first
propeller they neither assist nor retard the action of this propeller. When
however they are rotated in the opposite direction to that in which they are rotated
when going ahead, water will have free access to them and the vessel will be caused
to go astern.
To destroy or lessen the rotary movement of the annular stream of water forced
in a forward direction through the tube by the first propeller when going astern,
the forward end of the tube is or may be provided with a number of straight
guide plates or blades arranged external to or within the tube. When one propeller
only is used having its screw blades prolonged outward and forward as set forth,
hese blades must be suitably recessed or cut away near the outer edges so as to
clear the fixed radial blades or.plates.

page_text: COMPLETE SPECIFICATION.
Improvements in Propelling Apparatus for Ships or Vessels.
We, JOHN ISAAC THORNYCROFT of the firm of J. I. Thornycroft & Co. of
Church Wharf, Chiswick, in the County of Middlesex, Steam Yacht and Launch
Builders, and SYDNEY WALKER BARNABY of The Hollies, Chiswick Mall,
Middlesex, Naval Architect, 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 is designed to adapt for going readily astern (as well as ahead)
vessels fitted with propelling and steering apparatus of the kind described in the
Specifications of the English Patents No. 1330 of the year 1879, and No. 1853 of
the year 1881, both granted to one of us namely the said John Isaac Thornycroft.
The said apparatus can be constructed in various forms as is well known, and the
present invention can be applied in conjunction with various arrangements of
the said propelling and steering apparatus (hereinafter called for distinction
the "Thornycroft Propeller") of which some arrangements are illustrated by way
of example in the accompanying drawings.
Referring to these drawings,
Figs. 1, 2 and 3 shew three modifications of the present invention; each figure is
a side elevation, partly in section.
Fig. 4 is a side elevation of the after portion of a twin propeller vessel adapted
for shallow water and having this invention applied to it.
Fig. 5 is a plan of the same, and
Fig. 6 is a transverse section.
As will be seen in each arrangement the Thornycroft propeller comprises
essentially a propeller A B having behind it, and arranged in line with its boss A,
a body C (hereinafter called the rearward body") that has a gradually increasing
diameter or width for a short distance, and afterwards a gradually diminishing
diameter or width to its rearward end, and is furnished with guide plates or blades D
for gradually deflecting and directing the water projected from the propeller A B
into a direction approximately parallel with the axis of the rearward body C, the
said propeller A. B, rearward body C and guide plates or blades D, being
surrounded by a fixed pipe, tube, case or hollow guide E (hereinafter called a
"tube").
Now in order that a navigable vessel fitted with the Thornycroft propeller may
be made capable of readily going astern when necessary, according to the present
invention supplementary blades (constituting a sternway propeller or propellers)
are arranged in conjunction with, or combined with, the Thornycroft propeller and
its shaft F, and these supplementary blades are arranged so as to be outside of and
at the forward end of, the tube E. The supplementary blades G may be carried
by a boss H (or bosses) mounted on the same shaft F as the propeller A B so as to
be directly in front of, but separate from the propeller A B as shown in Figs. 1
and 2. Or, instead of forming a separate propeller G H, the screw blades of the
Thornycroft propeller A B may be formed with prolongations or extensions G*
that extend some distance beyond the forward end of the tube E as shown in
Fig. 3. In either case, it is advantageous that the screw blades G, (Figs. 1 and 2)
or the portion G* of the screw blades A B (Fig. 3) that are external to the tube E,
should be of such a uniform pitch that, during the forward movement of the vessel
caused by the Thornycroft propeller, the said supplementary blades G or part
blades G shall neither assist nor retard the action of the Thornycroft propeller.
When however the blades G or blades B G* are rotated in the opposite direction
to that in which they are rotated when going "ahead," water will have free access
to them, and the vessel will be caused to go astern.
To destroy or lessen the rotary movement of the annular stream of water forced

page_text: in a forward direction through the tube E by the Thornycroft propeller, when
going astern, the forward end of the tube E is (or may be) provided with a number
of straight guide plates or blades I, arranged within the tube E, as shown, or they
may be external to the tube. When one propeller only is used, having its screw
blades prolonged outward and forward as set forth, these blades must be suitably
recessed or cut away near the outer edges as shown at K, Fig. 3 so as to clear the
fixed radial blades or plates L.
In Fig. 7 the shaft F is prolonged to the forward end of the vessel and the
supplementary blades G are fixed upon that end of the shaft.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
For enabling a vessel to be driven astern, the use in conjunction with a
Thornycroft propeller which is adapted to drive the vessel ahead, and comprises
a rotary propeller, a rearward body, curved guide plates or blades such as D and a
tube (provided
or not with straight guide plates or blades) such as I within which
the said propeller works, of supplementary blades or blade extensions mounted on
the same shaft as the rotary part of the Thornycroft propeller, but so as to be
outside of the tube, and in front of it, and so constructed and arranged, whether
on a separate boss (or bosses) as in the examples Figs. 1 and 2; or forming
extensions of the rotary part of the Thornycroft propeller, as in Fig. 3, that when
the vessel is being driven ahead they will not retard its progress, and when the
direction of motion of the shaft is reversed they will drive the vessel astern,
substantially as hereinbefore described.
JOHN I. THORNYCROFT.
SYDNEY W. BARNABY.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.