Improvements in the Construction of Steamships and similar Vessels.
Year: 1891

page_text: Date of Application, 7th July, 1891
Complete Specification Left, 7th May, 1892-Accepted, 2nd July, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Steamships and similar
Vessels.
I, HENRY GEORGE DUNSTAN of Pillgwenlly, Newport, in the County of
Monmouth Preferenco Outdoor Officer (Customs) do hereby declare the nature
of this invention to be as follows:-
The object of this invention is to construct steamships and similar vessels in
such a manner that the propellor never leaves the water thereby preventing the
racing of the engines as frequently happens in a heavy sea with the steamships as at
present constructed. The position of the propellor also is such that it is immersed in
comparatively still water.
In vessels as at present constructed the propellor is generally arranged to work
in bearings at or near the stern post and in all cases in close proximity to the rudder.
The arrangement of the propellor in this position has its disadvantages especially
in rough weather as when the vessel pitches forward in a heavy sea the propellor
is often thrown right out of the wator thus causing the engines to race or overrun
their proper speed whereby there is great risk of their breaking down or of the
propellor itself being wrenched from its bearings which also in most cases
causes serious damage to the steering gear thus leaving the vessel in a helpless
condition.
According to this present invention I arrange the engines amidships and instead
of having the propellor shaft running from the centre of the vessel to the end
thereof shorten the same considerably, by connecting the propellor to its shaft
as near as possible to the engines, a suitable cavity being made underneath the
vessel for the reception thereof. When constructing a vessel according to this
invention sufficient room should be allowed for the propellor to work entirely-
olear of the keelson in order to. obviate the danger of the propellor coming into
contact with any obstructions when in shallow water.
By arranging the engines and propellor in the position already referred to, I am
enabled to gain considerable cargo space by not having the propellor shaft running
down the centre of the vessel to the stern thereof, at the same time the propellor is
entirely protected from the dangerous effect of heavy seas and the racing of the
engines and loss of, or damage to the propellor is entirely obviated. I also construct
the vessel with the water tight ballast tanks surrounding the amidships cavity in
which the propellor works instead of arranging the ballast tanks fore and aft as
heretofore. By this means I provide greater stability to the vessel and leave
more room for cargo in the fore and aft holds.
To prevent the vessel sticking in the mud when at low tide in shallow waters
I provide one or more pipes through which air is conveyed to the amidship
cavity in which the propellor works.
CASTLE SMITH,
"Invention" Office, 54, Fleet Street, London, E.C.,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION:
Improvements in the Construction of Steamships and similar
Vessels.
1, HENRY GEORGE DUNSTAN, of Pillgwenlly, Newport, in the County of
Monmouth, Preference Outdoor Officer (Customs), 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 object of this invention is to construct steam-slips and similar vessels in
such a manner that the propeller never leaves the water, thereby preventing the
racing of the engines as frequently happens in a heavy sea with the steam-ships
as at present constructed. The position of the propeller also is such that it is
immersed in comparatively still water.
In vessels as at present constructed the propeller is generally arranged to work
in bearings at or near the stern post and in all cases in close proximity to the
rudder. The arrangement of the propeller in this position has its disadvantages
especially in rough weather as when the vessel' pitches forward in a heavy sea the
propeller is often thrown right out of the water thus causing the engines to race
or over-run their proper speed whereby there is great risk of their breaking down,
or of the propeller itself being wrenched from its bearings which also in most
cases causes serious damage to the steering gear thus leaving the vessel in a helpless
condition.
According to this present invention. I arrange the engines amidships and instead
of having the propeller shaft running from the centre of the vessel to the end
thereof, I shorten the same considerably by connecting the propeller to its shaft as
near as possible to the engines, a suitable cavity being made underneath the vessel
for the reception thereof. When constructing a vessel according to this invention
sufficient room should be allowed for the propeller to work entirely clear of the
keel in order to obviate the danger of the propellor coming into contact with any
obstructions when in shallow water.
By arranging the engines and propeller in the position already referred to I am
enabled to gain considerable cargo-space by not having the propeller-shaft running
down the centre of the vessel to the stern thereof, at the same time the propeller
is entirely protected from the dangerous effect of heavy seas, and the racing of
the engines and loss of damage to the propeller is entirely obviated. I also construct
the vessel with the water-tight ballast tanks surrounding the amidship cavity in
which the propeller works, instead of arranging the ballast tanks fore and aft as
heretofore. By this means I provide greater stability to the vessel, and leave
more room for cargo in the fore and aft holds. To prevent the vessel sticking in
the mud when at low tide in shallow waters I provide one or more pipes
through which air is conveyed to the amidship cavity in which the propeller
works.
.
And in order that iny invention may be more fully understood and carried into
practice I will now proceed to describe the same with reference to the accompanying
two sheets of drawings.
Figure 1 shews a longitudinal vertical section of the central portion of a steam-
ship constructed according to this invention;
Figure 2 is a sectional plan taken at the line 1, 1, Figure 1;
Figure 3 a transverse vertical section taken at the line 2, 2, Figure 1, and
looking aft;
Figure 4 is a section at the same line looking forward;
Figures 5 to 7 illustrate the invention applied to a vessel with twin screws,
Figure 5 being a longitudinal vertical section, Figure 6 a sectional plan, and
Figure 7 a transverse vertical section.
The cavity A is formed in the hottam of the contual
1
1

page_text: the propeller B, which may be supported at the extremity by a wedge-shaped
part of the hull C (Figs. 1 to 4) projecting into the said cavity A. The said
projecting part C forms part of the engine room so that the length of the propeller-
shaft D may be reduced to a minimum. Air tubes E open into the upper part of
the cavity A and communicate with the deck in order to establish communication
with the atmosphere and so prevent the creation of a vacuum at low tide within
the said cavity.. By this means it will be impossible for the vessel to stick in the
mud in shallow waters.
Water tight ballast tanks are arranged within the spaces F surrounding the
amidship cavity. This arrangement gives greater stability to the vessel and leaves
more room for cargo in the forward and aft holds.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
alaim is:-
The construction of ships' hulls with an amidship cavity or cavities for the
reception of the propeller in the case of steam-ships substantially as and for the
purpose hereinbefore set forth and described and illustrated in the accompanying
CASTLE SMITH,
"Invention." Office, 54, Fleet Street, London, E.C.,
Agent for the Applicant.