IMPROVEMENTS IN OR APPERTAINING TO SUBMARINE OR SUBAQUEOUS BOATS OR VESSELS
Year: 1881

page_text: LETTERS PATENT to Thorsten Nordenfelt, of No. 1, Saint Swithin's Lane, in
the City of London, Civil Engineer, for an Invention of "IMPROVEMENTS IN
OR APPERTAINING TO SUBMARINE OR SUBAQUEOUS BOATS OR VESSELS."
PROVISIONAL SPECIFICATION left by the said Thorsten Nordenfelt at the
Office of the Commissioners of Patents on the 17th February 1881.
THORSTEN NORDENFELT, of No. 1, Saint Swithin's Lane, in the City of London,
Civil Engineer.
"IMPROVEMENTS IN OR APPERTAINING TO SUBMARINE OR
SUBAQUEOUS BOATS OR VESSELS."
This Invention has for its object improvements in or appertaining to submarine
or subaqueous boats or vessels.
I construct the hull of my vessel to withstand the pressure of the water and to
pass readily through the water and attain as much speed as the engine power
admits. Preferably I construct the hull of such proportions that laterally its
section is a perfect circle, and a line drawn from bow to stern through the centre
forms a chord to any longitudinal section of the skin.
The boat is propelled by an ordinary screw propeller, which is actuated by a
steam engine. The boiler is so constructed that although the fire door, ash pit
door, and funnel can be hermetically closed yet it continues for a limited time to
supply the engine with the steam necessary to keep it in motion.
For the purpose of causing the descent of such boats or vessels below the surface
of the water I do not rely upon vertical steering apparatus, nor do I cause the
vessel to descend by gravity, as has been done heretofore, but I effect the descent
by the direct application of power to that end.
The descending apparatus which I employ consists of an upright tube or tubes
passing through the vessel and containing a screw or screws which can be driven
by shafting passing through stuffing boxes from the interior of the vessel. The
boat or vessel has a small amount of buoyancy, and consequently rises to the
surface whenever the rotation of the screws and the application of power is
suspended.

page_text: To prevent the boat or vessel from deviating far from an horizontal position
when afloat I provide automatic steering gear, which corrects any deviation from
the horizontal by steering the nose of the boat or vessel upwards or downwards.
I arrange in the bow two side rudders upon an axle which runs horizontally
through the skin of the boat or vessel. Upon the shaft within the boat or vessel
there is an arm which is controlled by a piston working in a cylinder.
Water or
fluid under pressure is admitted to the cylinder either on one or other side of the
piston as may be required by a valve governed by a plumb weight. When the
boat or vessel is upon an even keel the plumb weight holds the valve in a middle
position, in which it closes both of the passages leading to the cylinder ends, but a
deviation of the boat or vessel from the horizontal position causes the valve to
uncover one of the cylinder ports to the supply and the other to the exhaust, and
the vertical rudders are thus moved to steer the nose of the boat or vessel
upwards or downwards, as may be required, to correct the previous deviation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thorsten Nordenfelt in the Great Seal Patent Office on the
17th August 1881.
THORSTEN NORDENFELT, of No. 1, Saint Swithin's Lane, in the City of
London, Civil Engineer. "IMPROVEMENTS IN OR APPERTAINING TO SUBMARINE OR
SUBAQUEOUS BOATS OR VESSELS."
This Invention has for its object improvements in or appertaining to submarine
or subaqueous boats or vessels.
I construct the hull of my vessel to withstand the pressure of the water and to
pass readily through the water and attain as much speed as the engine power admits.
Preferably I construct the hull of such proportions that laterally its section is a
perfect circle, and a line drawn from bow to stern through the centre forms a chord
tó any longitudinal section of the skin.
The boat is propelled by an ordinary screw propeller, which is actuated by a
steam engine. The boiler is so constructed that although the fire door, ashpit door,
and funnel can be hermetically closed, yet it continues for a limited time to supply
the engine with the steam necessary to keep it in motion.
For the purpose of causing the descent of such boats or vessels below the surface of
the water I do not rely upon vertical steering apparatus, nor do I cause the vessel
to descend by gravity, as has been done heretofore, but I effect the descent by the
direct application of power to that end.
The descending apparatus which I employ consists of an upright tube or tubes
and containing a screw or screws which can be driven by shafting passing through
stuffing boxes from the interior of the vessel. The boat or vessel has a small amount
of buoyancy and consequently rises to the surface whenever the rotation of the
screws or the application of power is suspended.
To prevent the boat or vessel from deviating far from an horizontal position
when afloat I provide automatic steering gear which corrects any deviation from
the horizontal by steering the nose of the boat or vessel upwards or downwards. I
arrange in the bow two side rudders upon an axle which runs horizontally through
the skin of the boat or vessel. Upon the shaft within the boat or vessel there is
an arm which is controlled by a piston working in a cylinder. Water or fluid
under pressure is admitted to the cylinder either on one or other side of the piston
as may be required by a valve governed by a plumb weight. When the boat or
vessel is upon an even keel the plumb weight holds the valve in a middle position,
in which it closes both of the passages leading to the cylinder ends, but a deviation
of the boat or vessel from the horizontal position causes the valve to uncover one of
the cylinder ports to the supply and the other to the exhaust, and the vertical
rudders are thus moved to steer the nose of the boat or vessel upwards or down-
wards as may be required to correct the previous deviation.
In order that the said Invention may be most fully understood and readily carried
into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
On Sheet 1 of the Drawings the general construction of the boat is shewn in 6
views. Figure 1 is a sectional elevation. Within the boat are two hot water tanks.
A and A¹ and the boiler B. F is its telescope funnel; E is the condenser; and e

page_text: side screws.
K' is a tank at the sides and bottom, into which sea water can be
taken for the purpose of regulating the amount of buoyancy to be overcome by the
action of the side screws. e is the engine which operates the longitudinal stability
rudders R; T is the moveable conning tower.
Figure 2 is a plan of the boat with such parts of the skin or shell removed as to
show the two hot water tanks A and A¹, the boiler B, the condenser E, the main
engine e, the side screws or descending apparatus 8, s, and the engine e¹¹ for working
the longitudinal stability rudders R. The hot water tank A¹ is represented in
section. This figure also shows the pumps P1, P², P³. The duty of these pumps is
as follows-P¹ takes from the hot water tank A and discharges into boiler B;
P3 takes from the boiler B and discharges into the hot water tank A'; P³ takes
from A and discharges into A.
The object of these pumps is that there shall be a complete circulation of the
water over the heating surface of the boiler B, whilst a perfect control of the
quantity of water in each of these reservoirs is always maintained.
Figure 3 is a transverse section taken amidships and looking towards the bow of
the boat. It shews the side sinking or vertical propelling apparatus s, s, the
boiler B, the funnel box F, the conning tower T, and the cold water tank t.
Figure 4 is to a smaller scale an end view of the boat.
Figure 5 is an elevation of the boat when arranged for submarine work and just s
before the side screws begin to operate, a being the water line.
Figure 6 is an elevation of the boat when prepared for surface work; the
funnel F and the conning tower T being raised project from the deck.
Sheet 2 of the Drawings shows detail of the descending apparatus.
Figure 7 is a vertical section to a large scale through the tube in which one of
the descending screws S works. It is driven, as will be seen, by bevilled gear from
the shaft of its motor engine, which passes through the side of vessel by a stuffing
box.
Figure S is a plan of the descending apparatus.
Figure 9 is an horizontal section of a tank.t extending in front of and behind the
descending screw S.
Figure 10 is a vertical section of the tank t.
Sheet 3 of the Drawings shows the apparatus in connection with the how rudders,
which tends at all times when the vessel is in motion below the surface to prevent
upward or downward deviation, and to cause the forward motion to be in an
horizontal plane.
Figure 11 is a plan of the controlling cylinder.
Figure 12 is a plan of a portion of the longitudinal stability rudders R with their
cranked axis R¹. The sides of the vessel are seen in section.
'
Figure 13 is a vertical section of the controlling cylinder with its valve.
Figure 14 is a vertical section of the fore part of the vessel, and shows the
cranked axis R' and a part of the connecting rod by which it is coupled with the
piston rod of the controlling cylinder.
Figure 15 is a transverse section of the controlling cylinder and valve.
The valve V is of the rotary or plug valve class; it is fixed upon a spindle, to
which an arm is also attached, and the arm carries a weight W. The arm maintains
approximately a vertical position, and when the vessel is horizontal the valve V
occupies the position in which it is seen in Figure 13. There is a small accumulator
or air vessel kept charged by a pump, and from this water under pressure is supplied
to the chamber in which the valve works. Any deviation of the vessel from an
horizontal position causes the water under pressure to enter the cylinder and give
motion to the piston and consequently to the longitudinal stability rudders R in a
manner to correct the deviation.
In preparing the vessel to descend the water in the boiler B and in the hot
water tanks A and A has first to be heated until the pressure in them is as high
as they are constructed to bear. The vessel at this time may be steaming at the
surface when she is navigated in the ordinary_way, being propelled by the stern screw

page_text: and steered by the stern rudder. When it is wished to descend the doors of the
boiler furnace are closed and secured; the doors are made to shut gas tight. The
funnel is then lowered and closed by a tightly fitting cover, which also fits water-
tight to the side of the vessel. The conning tower also is similarly closed and
lowered down. Water is then admitted carefully to the tanks, and the descending
apparatus S, S, is set gently to work. This apparatus will take the vessel down
whilst she is still somewhat lighter than the water displaced. As soon as the
gauge indicates that the vessel is descending the admission cocks to the tanks are
closed, and they remain closed whilst the vessel is down, the depth at which she
travels beneath the surface being controlled by driving the descending apparatus a
little faster or slower as may be necessary. The vessel is propelled and steered by
the stern propeller and rudder as when at the surface.
The vessel contains sufficient air for the use of the navigators whilst remaining
down for a considerable time, and artificial means may be resorted to to maintain
its purity, as is well understood. A valve is provided (to be operated by a treddle
or otherwise) by which the hot water can be allowed to escape from the boiler and
vessels A and A' into the sea. By opening this valve the vessel can in case of
necessity be almost instantly brought to the surface at any time. This arrange-
ment ensures safety even in the case of the vessel becoming injured by collision or
otherwise so as to leak seriously.
It will be seen that by burning fuel in the vessel when she is at the surface I
store up power in the form of highly heated water, and that I employ this
power to propel the vessel when submerged and also to regulate the depth of
submergence.
Having thus described the nature of my said Invention and the manner of
performing the same, I would have it understood that I claim as my improvements
in or appertaining to submarine or subaqueous boats or vessels,-
First. Providing the said vessels with propelling engines and boiler, the latter
being so arranged that after the water has been heated by the combustion of fuel
its furnace may be closed gas tight and the steam from the heated water used to
drive the engines whilst the vessel is submerged.
Second. Providing the said vessels with descending or vertical propelling
apparatus, which whilst in motion is capable of sinking the vessel beneath the
surface whilst the vessel is lighter than the water which it displaces.
Third. Providing the said vessel with automatically acting longitudinal stability
rudders controlled by hydraulic or other motor apparatus and a plumb weight.
In witness whereof, I, the said Thorsten Nordenfelt, have hereunto set my
hand and seal, this Second day of August, in the year of our Lord One
thousand eight hundred and eighty one.
THURSTEN NORDENFELT (L.S.)