Improvements in and relating to Subaqueous Torpedo and Gun Boats, and the Armament thereof.
Year: 1892

page_text: Date of Application, 20th Apr., 1892-Accepted, 2'st May, 1892
COMPLETE SPECIFICATION.
Improvements in and relating to Subaqueous Torpedo and Gun
Boats, and the Armament thereof.
I, JOHN PHILIP HOLLAND, of 185, Court Street, Newark, in the County
of Essex and State of New Jersey, United States of America, (rentleman, 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 relates to that class of torpedo or gun boats commonly termed
subaqueous boats; its object being to provide a torpedo or gun boat in which the
maximum of protection for both boat and crew is combined with the necessary
accuracy in steering, the greatest allowable speed, destructiveness and steadiness;
whereby it is possible to begin the attack at a distance of from one to two thousand
yards, and then for the boat to be brought near enough to a man-of-war to apply
or discharge a submerged torpedo with little risk of injury.
In the accompanying drawings, which illustrate the present invention,
Fig. 1 is a longitudinal section of the boat, the section being taken centrally,
except as regards the stern-portion, where it is taken on the line a a in Fig. 2.
Fig. 2 is a view partly in plan and partly in horizontal section; the plane of the
section being just below the deck of the boat or crown-plate of the shell.
Fig. 3 is an end elevation of half the boat shewing the form of the bow; Fig. 4
being a similar view of the stern of the boat.
Fig. 5 is a side elevation of the stern.
Figs. 6, 7, 8, 9, 10) and 11 are cross sections of the boat in the several planes
indicated respectively by the lines b, c, d, e, f and in Fig. 2.
Fig. 12 is a section, drawn to an enlarged scale, representing a detail hereinafter
more particularly referred to.
The form of the shell or body of the boat is sufficiently explained by the
drawings. The means of propulsion comprise twin screws 1 driven by the
engines 2, which are supplied with steam from the boilers 3. The steam-boiler
furnaces are provided with a smoke-stack 4; the same being arranged amidships.
The boat is furnished, for ordinary lateral steering, with a rudder 5. The arma-
ment of the boat comprises a submerged gun 6 placed at the bow, a submerged
gun 7 located at the stern and arranged between the screws 1, two inclined
over-water guns 8 directed fore and aft respectively, and a light quick-firing gun 9
with a shield mounted on a platform near the stack and always above the
water-level.
10 is the forward gun-room, 11 the aft gun-room and 12 the central gun-room
and cabin. In the bow there is a water-ballast chamber 13. On the deck or
upper part of the shell of the boat is mounted an armoured caisson 14, which
embraces the lower portion of the smoke-stack + and the air-shaft 15 adjacent to
the latter. The forward part of the caisson 14 is fitted up as a conning tower 16
for the steersman, and the aft part of the same constitutes a protected companion-
way 17. Around the top of the companion-way is placed a platform 18, on which
the quick-firing gun 9 is pivoted centrally.
On the deck of the boat, and extending fore and aft, is a narrow hollow super-
structure 19, which is tapered laterally toward the bow and stern to form a
cut-water when the boat is submerged; the resistance to the motion of the boat
being thus reduced. In the ballast-chamber 13 are placed the compressed
air-reservoirs 20.
In Fig. 1, the line W. L. 1. indicates the normal water-line when the boat is not
in action. The line W. L. 2. denotes the water-line when the boat is submerged

page_text: and prepared for action. Ine line w. L. 5. snows the water-fine when the boat 5
rapidly advancing to the attack.
After this brief description of the general construction of the boat, I will procced
to describe the manner in which the boat is submerged and controlled.
The buoyancy of the boat is such that, normally, the water-line is at W. L. 1.
To submerge the boat, water is admitted to the chamber 13 at the bow, which sinks
it gradually to W. L. 2.; the water entering the superstructure 19 through
apertures 21 placed close to the deck or crown-plate of the boat. The apertures 21
near the bow of the boat are provided with valves or hinged covers opening
outwardly, which prevent the water from entering when the boat is running ahead
and not submerged, but allow the water to flow freely out of the superstructure
when the boat rises on the pumping out of the water-ballast from the chamber 13.
The superstructure is built higher at the centre adjacent to the caisson in order
that such part may remain empty and buoyant for a longer time than the end
portions during the submerging operation, so that the boat may preserve an even
keel while sinking. When rising, the central part is first emptied. The vessel,
being thus lightened over the centre of buoyancy, will rise on an even keel.
The boat, having been submerged to the line W. L. 2., is ready to attack.
Advancing rapidly, the bow is depressed through the medium of a pair of vertically-
operating rudders 22 placed on cach side of the stern, as seen in Fig. 2. These
rudders are fixed to a horizontal shaft 23, which has a crank 24 placed over the
stern gun 7. Coupled to this crank is a rod 25, which extends forward and is
connected to a lever 26. To the upper end of this lever is jointed a rod 27, which
is attached at its forward end to an operating lever 28 in the conning tower 16.
There are a series of peep-holes, as usual, in the walls of the conning tower, which
enable the steersman to direct the course of the boat through the medium of the
ordinary steering apparatus. When he has headed the boat for the ship or other
object of attack, he uses the lever 28 to deflect the rudders 22, whereupon the
forward motion of the boat causes it to sink to the line W. L. 3. The maximum
degree of deflection of the rudders 22 having been determined beforehand, a stop
is provided which prevents the operating lever from being moved too far.
The over-water guns 8 may, of course, be fired at a greater range than
the subaqueous guns 6 and 7, but the range or distance depends in a great degree
on the size and character of the respective guns. The projectiles may contain high
explosives, and any suitable explosive, or compressed air, etc., may be used for
projecting them. The quick-firing gun 9 may be of any approved pattern, and is
intended for a protection against attacks by torpedo or other boats.
The boat depends on the buoyancy of the armoured caisson, particularly the
large portion thereof enclosed by the superstructure, to prevent it from sinking to the
bottom when submerged. In order for the caisson to be effective, its volume must
be considerable, say from four to five per cent, of the total volume of the hull, and
it must be placed over or slightly in advance of the centre of displacement of the
submerged hull. A smaller proportionate volume, one or two per cent. for example,
would be wholly ineffective for the purpose, as the vertical motion caused by
passing waves of considerable:ize would be apt to cause the vessel to founder by
submerging the top of the air-shaft and of the smoke-stack. A much larger
proportionate volume for the caisson is also inadmissible, for the reason that
the extra weight of the armour could not be carried, and also because the
augmented bulk and width would increase correspondingly the width of the
superstructure. In a horizontal plane, the caisson must have sufficient area for a
pilot-house, an air-shaft and a smoke-stack, and, as the roof of the pilot-house must
be armoured and immovable, companion-ways must also be provided in the caisson.
The caisson should be as narrow as possible in order that the cross section of the
surrounding superstructure which opposes itself to the progress of the vessel may
be as small as possible. I prefer to arrange the pilot-house, air-shaft, smoke-stack
and companion-way in the order named, the pilot-house and conning tower being in
front. As the function of the superstructure is in part to provide a cut-water in

page_text: front of the caisson, which latter would otherwise offer too great a resistance to the
movement of the boat through the water, it is inadmissible to enlarge the cross
section of this superstructure for the reason that this would make the resistance
above the axis of the boat too great and thus increase the tendency of the boat to
lift forward when under way.
In order that the boat may run steadily when submerged to the line W. L. 2.,
equal moments of resistance to forward or backward motion are provided above
and below the axis of the boat, which is in the plane of the screw-shafts and
submerged guns. The upper moments of resistance are calculated from this axis
up to W. L. 2.
When the boat is submerged to W. L. 3., thus putting five feet of water over its
body or shell, the resistance offered by the submerged portion of the caisson
between W. L. 2. and W. L. 3. to movement through the water produces a force
which tends to turn the boat about a transverse axis passing through the centre of
buoyancy and so lift its forward end. This tendency is counterbalanced by the
inclined rudders 22. Should the boat happen to reach a greater degree of sub-
mergence than to W. L. 3., the moment of resistance above the axis will be
increased and the added pressure acting on the caisson near its top will cause an
increased tendency in the boat to rise at its forward end. As it is important that
this lifting force in case of excessive submergence shall be effective, the part of the
caisson exposed above W. L. 3. should be made as large as possible without undue
increase of weight, and the exposed part should be placed at a distance above the
centre of buoyancy which is approximately equal to the depth of the boat. In the
design shewn, the transverse section of the part exposed above W. L. 3. is eight
per cent. of the entire transverse section of the boat at this point, and this I deem
the minimum to be effective. This exposed portion is at a distance above the
centre of buoyancy which is about equal to the depth of the boat.
As a further protection against excessive submergence, the air-shaft and the
smoke-stack above the top of the caisson are made square or oblong in cross section,
so that, if submerged while the boat is advancing, their flat surfaces may offer such
resistance to movement through the water as will serve instantly to raise the
forward part of the boat and prevent the boat from foundering. The lower portion
of the boat, of the smoke-stack and of the air-shaft are built of metal strong
enough to withstand the impact of the waves.
The weight of the armoured caisson 14 and the superstructure 19 are counter-
balanced by a corresponding weight of ballast 29, which is placed at the bottom of
the boat.
The air-shaft 15 and the smoke-stack 4 are strong enough to withstand the
buffeting of the waves, and their stanchness may be increased by a triangular
brace 30, which connects the said shaft with the superstructure.
It is possible that in action a shot may perforate both the air-shaft 15 and the
smoke-stack 4, in which case the smoke and products of combustion would be drawn
through the shot-holes and down the shaft into the boat. To obriate this
difficulty, I leave a narrow space 31 between the shaft and the stack, and arrange
therein a slide or screen in the nature of a thin metal plate, which is adapted to be
pushed up from the cabin 12 far enough to close the shot-hole in the stack and
prevent the escape of gases thereat to any injurious extent. This slide may be
constructed and operated in any convenient manner. In Fig. 1, I shew the screen
or slide 32 provided with a stem 33, which extends through the deck of the boat
down into the cabin or gun-room 12; preferably passing through a packed opening
or gland therein to prevent leakage.
On the superstructure, in front of the conning tower, there may be placed
a wave-cutter 34, which may be in the form of an angular plate designed to
cut or break the waves and prevent them from dashing into the sight-holes of the
tower.
I have stated that one function of the superstructure 19 is to serve as a
cut-water; but it has another important function. The apertures 21 in the

page_text: superstructure are so small, and so few in comparison with the capacity of the
superstructure, that the latter fills and empties slowly, and thus the submergence
or lifting of the boat is effected gradually. When the superstructure is above the
water-level, very little water from the dashing of the waves over the body of the
boat can enter at these apertures.
In Fig. 12, I have shewn the valves 35 which close two of the forward
apertures 21 in the superstructure.
As a bow-depresser, instead of the rudders 22, a shifting ballast-weight arranged
over the keel amidships, and adapted to be moved forward so as to depress the bow
when the boat is going into action, may be employed.
I have not deemed it necessary to illustrate or describe the mechanism for
pumping or blowing the water from the chamber 13 for steering, for ventilating,
etc., as this may be of the usual or any kind.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
:-
1. A torpedo or gun boat provided with means for completely submerging its
hull, and having mounted thereon, near or at the centre, a hollow armoured air-
tight caisson surrounding the smoke-stack, the air-shaft and the companion-way,
and an enclosed superstructure provided with comparatively small apertures for the
admission or escape of water, the caisson serving by its buoyancy to suspend the
submerged boat, and the superstructure to gradually retard the sinking of the hull
while the same is being submerged.
2. A torpedo or gun boat provided with means for completely submerging its
bull and having erected thereon, near or at the centre, a hollow armoured air-tight
caisson, capable of being nearly submerged, and which provides the necessary
buoyancy for suspending the hull in the water at the proper depth.
3. A torpedo or gun boat provided with means for completely submerging its
hull, and having a hollow air-tight caisson on its deck over the centre of volume,
which by its buoyancy suspends the submerged hull, and also companion-ways and
air-tight doors in the deck leading from the caisson to the various compartments in
the hull.
4. A torpedo or gun boat provided with means for submerging its hull, and
having a hollow air-tight caisson over the centre of volume whereby it is suspended
in the water, and also air-tight doors in its deck leading from the caisson to the
compartments in the hull, and on its deck a hollow covered superstructure with
pointed ends and relatively small apertures to admit water or allow water to escape,
the superstructure enclosing the lower part of the caisson.
5. A torpedo or gun boat having mounted on its deck a hollow air-tight caisson
arranged over the centre of volume, a covered superstructure which encloses the
lower part of the caisson, a water-chamber within its hull of sufficient capacity to
submerge the bull and superstructure and to nearly submerge the caisson, and
means for filling and emptying the water-chamber.
6. A torpedo or gun boat provided with means for submerging its hull and with
vertically-operating rudders for depressing its bow while in motion, and also
having mounted on its deck a hollow air-tight structure which projects upward
and regulates the degree of enforced submergence of the hull by its resistance and
buoyancy.
7. A torpedo or gun boat having a smoke-stack and an air-shaft arranged side
by side and provided with a screen to close a shot hole if made therein, the screen
being provided with means, substantially as described, for operating it from the
inside of the boat.
Dated the 00h 1
11000
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.