Year: 1887

page_text: Date of Application, 19th Feb., 1887
Complete Left, 21st Nov., 1887
Complete Accepted, 23rd Dec., 1887
I, THOMAS RIDLEY OSWALD of Woolston, in the County of Southampton, Ship-
builder and Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention has for its object improvements in twin screw ships or vessels. In
the specification of a former patent granted to me the 9th day of February 1882
No. 628 is described a type of twin screw ship or vessel having two tails each formed
in such wise that the effective acting portion of each screw blade in its lowest position
shall project below the after part of the dead wood of the corresponding tail but not
below the keel line of the vessel; also the arranging two screws in planes one behind
the other with respect to the ship or vessel. It has reference to ending the formation
lines of the vessel aft in a bearding or cutting down line, and the carrying out from
the same at suitable points projections so formed and placed as to carry the shafts of
the screws. These may be arranged as may be found desirable, the arrangement
may be such that the screws will overlap or not; and when placed one in front of the
other (as referred to in my said former specification) and cutting each others plane
the screws may be of varying or different diameters or disc areas, either the foremost
or the aftermost being the larger, or both may have the same diameter or disc area.
The screws may in some cases be arranged to work alternately, partly below the keel
line of the vessel. There is an overhung rudder aft that passes through a stuffing
box. Disc faces and a ball thrust bearing are provided for taking thrusts as well as
carry the rudder. Its travel is limited by suitable stops.
A spare rudder that may also have disc faces and a ball thrust bearing is fitted
forward of the screws and between the screw shafts to be available for use in the
event of the after rudder failing. Means are provided whereby the spare rudder can
be locked when not in use-The rudders can be connected to any suitable steering
gear.
1002

page_text: I, THOMAS RIDLEY OSWALD, of Woolston, in the County of Southampton, Ship-
builder and 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 :-
My invention has for its object improvements in twin screw ships or vessels. In
the specification of a former Patent granted to me the 9th day of February 1882,
No. 628, is described a type of twin screw ship or vessel having two tails each formed
in suchwise that the effective acting portion of each screw blade in its lowest position
shall project below the after part of the dead wood of the corresponding tail but not
below the keel line of the vessel: also the arranging two screws in planes one behind
the other with respect to the ship or vessel.
My present invention has reference to ending the formation lines of the vessel aft
in a bearding or cutting down line, and the carrying out from the same at suitable
points projections so formed and placed as to carry the shafts of the screws.
These
may be arranged as may be found desirable; the arrangement may be such that the
screws will overlap or not, and when placed one in front of the other (as referred to
in my said former specification) and cutting each others plane the screws may be of
varying or different diameters or disc areas, either the foremost or the aftermost
being the larger, or both may have the same diameter or disc area.
The screws
may in some cases be arranged to work alternately partly below the keel line of the
vessel. There is an overhung rudder aft that passes through a stuffing box. Disc
faces and a ball thrust bearing are provided for taking thrusts as well as to carry
the rudder. Its travel is limited by suitable stops.
A spare rudder that may also have disc faces and a ball thrust bearing is fitted
forward of the screws and between the screw shafts, to be available for use in the
event of the after rudder failing.
Means are provided whereby the spare rudder can be locked when not in use. The
rudders can be connected to any suitable steering gear.
Referring to the accompanying three sheets of illustrative drawings,
Fig. 1 is a side elevation of the stern portion of a twin screw ship or vessel formed
according to my invention.
Fig. 2 is a section in the horizontal plane of the centres of the two screw propeller
shafts.
Fig. 3 is an end view showing the arrangement of the bracket for supporting the
outer ends of the screw propeller shafts.
Fig. 4 represents a midship section of the ship or vessel and also half sections in
the lines A, A, and B, B, respectively of Fig. 1.
Fig. 5 is a vertical section of a stuffing box for the head of a rudder.
Figs. 6 and 7 are respectively an elevation and a part plan or-top view of a thrust
bearing and bracket for carrying and taking the thrust of an overhung rudder.
Fig. 8 is a section of a disc and ball thrust bearing for the rudder head which is
shown in elevation.

page_text: Referring to Figs. 1 to 4, it will be seen that the dead wood at the stern portion of
the vessel is removed and the formation lines are shown as ending in a bearding or
cutting down line. 1, 1* are projections carried out from the said stern portion of the
vessel and serving to carry the screw propeller shafts 2, 2ª, the outer ends of which
are carried by a bracket 3. The screw propellers 4, 4*, are shown arranged in planes
one behind the other according to the invention the subject of my former Patent
hereinbefore referred to, and overlapping, which arrangement has important advan-
tages when used in conjunction with my improved stern formation of the vessel.
5 is the after rudder which may be carried in any suitable manner but which
I prefer to carry in the manner hereinafter described with reference to the modified
form of rudder indicated by Fig. 5. 6 is a spare or supplementary rudder fitted
forward of the screw propellers and between the screw shafts. This spare or supple-
mentary rudder is locked, when not in use, by any suitable means as will be readily
understood. In Fig. 5, 7 is a stuffing box through which the head 8 of a rudder of
any suitable form may work. The stuffing box is formed with a stop 9, which in
conjunction with a stop 10 formed on the rudder head, serves to limit the travel of the
rudder through a suitable angle, say 40°.
In Figs. 6, 7. and 8, the upper part of the rudder head 8 is shown provided with a
disc, flange, collar, or annular projection 11 which is enclosed within a box 12
adjustable in a vertical sense within a bracket or frame 13. 14, 14, are screw threaded
bolts for effecting the vertical adjustment of tho box 12, and consequently the height
of the rudder. 15, 15, are anti-friction balls interposed between the upper and lower
faces of the disc, collar, or annular projection 11 and the top and bottom respectively
of the box 12, to reduce friction and enable the rudder to be more easily worked.
The arrangement described serves to hold up the rudder, and also as a thrust bearing
therefor.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The formation substantially as described of the stern of a twin screw ship or
vessel, the lines thereof ending in a bearding or cutting down line from which there
are projections for carrying the shafts of the screws.
2. A twin screw ship or vessel having its stern formed as described and its screw
propellers arranged in planes one behind the other.
3. A twin screw ship or vessel having its stern formed as described and its screw
propellers arranged in planes one behind the other and so as to overlap substantially
as hereinabove described.
4. Providing a twin screw ship or vessel with two rudders relatively arranged
substantially as described that is to say one aft of the screw propellers and the other
forward thereof with its head between the propeller shafts.
5. Hanging a rudder substantially as described, the arrangement being such that
the ball bearing will not only carry the rudder but also will take thrusts.
6. A twin screw ship or vessel having its stem formed as described, its propellers
arranged in planes one behind the other and overlapping; and provided with two
rudders one or each of which is hung substantially as described so that it is carried
by a ball thrust bearing that will take thrusts.
Dated this 21st day of Novembar 1987
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.