Year: 1888

page_text: Date of Application, 1st May, 1888
Specification Accepted, 1st June, 1888
A communication from abroad by WALFRID THEODOR SYLVEN, a citizen of Sweden,
residing at Washington, D.C., United States of America, Gentleman.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the County of Lancaster, and 323 High Holborn, in the County of Middlesex, Civil
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 :-
:
The aims of the invention are principally to improve the steering qualities of the
vessel, to render the action of the screws more efficient for the purpose of propulsion,
and to afford the rudder and the screws greater protection than is possible under the
ordinary modes of construction.
In twin screw vessels as usually constructed, the rudder is located at the centre
line of the hull abaft the propeller screws. In carrying the invention into effect, the
screws are located further astern than usual, and the rudder located forward of the
screws in the centre line of the hull, and in an opening formed through its stern or
stern frame.
In order that the screws and the rudder may be properly arranged and supported
in the above described relations, an improved stern-post or stern frame has been
devised, which is described in detail herein, and the use of which in substantially the
form shown is recommended; it is to be understood that any equivalent construction,
which will permit the screws and the rudder to be located in like relations to each
other, and to the hull, is included within the scope of the invention.
In building a vessel on this. plan the hull is made in approximately the form in
general use in twin screw vessels, but instead of hanging the rudder at the extreme
stern as usual, a strong rudder post or rudder frame is provided and built firmly into
the stern, having therein, forward of the transverse plane. in which the screws are
located, an opening to receive the rudder, which is thus permitted to swing through
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page_text: the stern forward of the screws from side to side. This frame is carried beneath the
rudder and rearward beyond the plane of the screws to the extreme rear end of the
under-water body, and serves as a shield or protection for both the rudder and
the screws, in the event of the vessel grounding or fouling at the stern.
In the accompanying drawings:
Figure 1 represents in side elevation the stern-post or stern-frame of a vessel
constructed on this plan, with the rudder and its connections in place, the relative
position of the screws being also shown in dotted lines.
Figure 2 is a horizontal section on a reduced scale through the stern portion of a
vessel on the line 1-1 of Figure 1, showing the stern-post, the rudder and the two
screws.
Figure 3 is a vertical transverse section on the line 2-2 of Figures 1 and 2.
Figure 4 is a cross section on the line 3-3 of Figure 1.
Figure 5 is a cross section on the line 4-4 of Figure 1.
Figure 6 is a horizontal section on the line 5-5 of Figure 1.
Figure 7 is an end elevation of the stern-post or frame, looking in a rearward
direction against its forward end.
Figure 8 is a cross section on the line 7-7 of Figure 1.
In Figures 1 and 2, A, B, C, D, E, F, G, represent the improved stern-post or
stern and rudder frame, which may be made of wrought iron, cast steel, or any
other suitable material in such form, that the part A B, form the after end of the
vessel's under-water body, and also serves as a shield for the propeller screws, which
are located forward thereof.
The part C, D, E, F, has an opening therethrough from side to side, adapted to
receive the rudder H, which is completely encircled thereby. The opening is made
of suitable size to admit of the rudder being readily shipped and unshipped. The
base portion of the frame F, G, is continued forward, and adapted like the forward
side of the portion E, F, and the top side of the portion D, E, to be built firmly into
the hull of the vessel.
When an ordinary rudder hung at its forward edge is employed, as shown in
the drawing, the portion E, F, of the frame is provided with rearwardly extending
lugs, to receive the pintles of the rudder. The top portion of the frame is suitably
enlarged, as shown at K, to admit the stuffing box as shown in Figures 1 and 3.
The frame is shaped at all points to conform to the shape of the particular hull to
which it may be applied, the frame being modified in form at the point of attach-
ment as circumstances may require in each case.
The rudder may be shipped or unshipped from either side of the vessel, and for
this purpose the hole K in the top of the frame will be suitably enlarged´athwart-
ships, as shown in Figure 3. The propeller screws will be located, as shown, one on
each side of the vessel, astern of the rudder, but forward of the extreme stern.
In place of the rudder shown, a balanced rudder having its axis of rotation at a
point between the front and rear edges, in a manner familiar to those skilled in the
art, may be employed. When the balanced rudder is employed with the axis located,
for example, in the line x-x of Figure 1, the frame will be provided at the base
with a suitable stop S', for the foot of the rudder. The lines P, P, P, indicate the
different shapes of a vessel's over-water body, which may be used in connection with
the frame.
The improved construction is attended with many advantages, among which may
be enumerated the following: The rudder head being located further forward, and
in a wider portion of the hull than usual, may be more conveniently fitted with
steering gear, and the steering devices connected at a greater distance from the axis
of the rudder-head, thus giving better command of the rudder; the rudder head as
well as the steering gear may be located further below the water line than usual, so
that in the case of war vessels they are less liable to injury, the rudder acting in solid
water, undisturbed by the screws, acts more efficiently, and thus gives greater control
of the vessel, the rudder being surrounded by the stern-frame, is protected from
injury in the event of the vessel running ashore; the stern or rudder frame extending

page_text: rearward between the screws, serves as an efficient guard or protection to prevent
the screws from being fouled or broken in case of the vessel grounding at the stern ;
the propellers being located further aft than usual, where the lines of the vessel are
finest, will act more efficiently in propelling the vessel, for the reason that the water
passes to them at a more favourable angle.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
1. A vessel having twin screws located on opposite sides of its centre line, and a
rudder located in its centre line, and in the opening therethrough forward of the
screws.
2. A twin screw vessel having the stern-frame or rudder-frame built therein, in
combination with the rudder mounted in said frame, forward of the screws, and
adapted to swing therethrough from side to side.
3. In combination with a common or balanced rudder, and two or more propellers
located astern and on opposite sides thereof, a protecting frame, A, B, C, D, E, F, G,
the forward portion having a suitable opening wherein the rudder is mounted, the after
portion serving as a shield for the propellers, and the lower portion serving as a shield
for the rudder in case of the vessel taking the ground, the whole frame forming part
and being securely connected to the hull of the vessel, as and for the purpose set
forth.
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