Year: 1899

page_text: I, MAURICE BOUCHET, of 22, Rue Alphonse de Neuville, Paris, France Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the hulls of vessels whereby the speed
will be largely augmented when the motive power is increased. With hulls of
ordinary form the motive power absorbed in propelling a vessel varies as the cube
of the speed and is moreover sensibly proportionate to the area of the immersed
midship section.
My invention has for object to enable an increased speed to be obtained with a
less amount of power than is required by the law above cited, that is to say so
that the motive power required shall increase in a lesser proportion than the cube
of the speed, this increase of speed being due to the lifting of the vessel which
reduces the area of the immersed midship section. The effect of thus raising the hulls
at very high speeds which is due as is known to the vertical reaction of the masses
of water set in motion by the hull has often been verified in the case of torpedo
boats for example, and the coefficient of utilization of the vessel has been thereby
increased, this coefficient being at a minimum which corresponds precisely to the
critical speed at which the lifting action commences. These facts are prefectly
well known but my invention consists in a special construction of the vessel's hull
which tends to cause the lifting of the vessel as soon as the speed increases, at
same time considerably reducing the area of the immersed midship section and
reducing to the utmost degree the critical speed, that is to say the speed at which
the lifting action commences.
According to this invention the hull presents at its lower part two walls merging
with the external form of the hull so as to form under the hull a sort of channel
of decreasing internal cross section which is constantly immersed and entirely
open at the underside and at the ends, the with diminishing from the bow end
to a given point in the length of the vessel in such manner that the vertical com-
ponent due to the reactions of the masses of water set in movement by the reduc-
tion of the sectional area of the channel shall act on the bottom of the hull and
exert a lifting action.
Reference is to be had to the accompanying drawings which illustrate by
way of example the construction of my improved kull. Figures 1, 2,
and 3 respectively represent al longitudinal section, underside plan,

page_text: and end elevation of a vessel. Figures 4, 5, and 6 respectively represent a plan,
longitudinal section, and end elevation of the immersed part of a hull whereof the
midship section is at mid-length. Figures 7 and 8 are transverse sections repre-
senting respectively the section at 3 (Figure 4) and the midship section MS.
Figures 9, 10, and 11 represent longitudinal sections of the immersed part of a
hull in three positions illustrating the lifting action; Figure 12 being a trans-
verse section shewing the diminution of area of the immersed midship section
when the vessel passes from the position shewn in Figure 9 to that of Figure 10.
Figures 13, 14, and 15 shew a modified form of vessel having the outer sides
inclined; Figure 13 being a longitudinal section, Figure 14 an underside plan, and
Figure 15 an end view shewing the forward sections F at one side and the aft
sections A at the other side of the vertical centre lines. Figures 16, 17, and 18
shew another modification of this type of vessel in which the external form, which
is constant, is constituted by curves terminating at two keels which limit the
water channel; Figure 16 being a longitudinal section, Figure 17 an underside
plan, and Figure 18 an end elevation shewing the forward and aft sections F
and A. The same letters of reference denote like parts in all the figures.
Referring to Figures 1, 2, 3, and 4, 5, 6, the hull has longitudinal side walls a
presenting at the inner side a longitudinally curved form such that the breadth of
free space left between the walls diminishes progressively from the bow end to a
given point in the length of the vessel and then again widens out to its original
dimensions at The stern, the sectional area of the channel thus formed by the two
sides and bottom of the hull thus varying continuously from a maximum to
a minimum amidships. The external water lines of the hull are absolutely recti-
linear lines and consequently the external form of the hull is constant and hence
all external displacement of masses of water by bow pressure and the throwing up
of a swell will be avoided. The external water lines of the walls a are therefore
right lines whereas their internal water lines are curves.
The midship section is placed at the middle of the vessel and the longitudinal
section of the bottom is either a right line joined to the bow and stern by curves
or is a continuous curve. Comparing two transverse sections the one 3 F (Figure 7)
and the midship section MS (Figure 8) it will be seen that the cross-section of
the channel at c, Figure 8, is less than that at d, Figure 7.
In the progress of the vessel the water confined between the two walls a and
the bottone of the hull must pass from space d to space c as the walls are per-
fectly rigid, the diminution in the sectional area from that shewn at d to that
shewn at e having the effect of exerting a pressure on the water so that the reaction
of the latter produces a vertical resultant which tends to lift the vessel. This
lifting action which increases with the speed diminishes the immersed midship
section and consequently the coefficient of utilization of the vessel increases. It
is to be understood that the speed of the vessel must be sufficient to exceed the
speed of transmission of pressures in the water.
The horizontal components of the pressures upon the internal surfaces of the
walls are symmetrical and mutually counteract each other. Under these con-
ditions the whole of the pressures upon the internal surfaces of the walls of the
water-way formed in the bottom of the hull have the effect of lifting the vessel.
In Figure 9 the vessel being stationary the displacement is represented by l
and when it has exceeded its critical speed (which is very low compared with that
which corresponds to ordinary forms of vessels) the displacement will be reduced
to (Figure 10) and the diminution of area of the immersed midship section will
be represented by (h-h¹) b; b Figure 12, being the breadth of said midship section.
The displacement may even be reduced to zero, as shewn in Figure 11, in which
case only the portions a a remain immersed.
Hence the cause producing the lifting effect persists after action and the parts a
remaining immersed the lifting gives rise to great stability. The stability is
very great since the breadth 6 of the midship section may, owing to the form of
the vessel, be made very considerable. This construction of hull is capable of

page_text: being carried out in many forms while the constant external form of the hull may
be that of a trapezium or rectangle with curved joining surfaces.
In the example shewn in Figures 13, 14, and 15, which as before represents
only the immersed portion of the hull, the external lateral surfaces are inclined so
that the external form of the vessel which is constant presents the form of a
trapezium. I, II, III, IV, WI, are the water lines up to the load water line;
1, 2, 3, 4, etc., are transverse vertical sections from amidships to the perpen-
diculars PP and PP, and MS the midship section which is at mid-length of
the vessel. The side walls may only commence in rear of the bottom proper
of the hull or they may project beyond the superstructure both at the bow and
stern.
The midship section which in the previous figures of the drawings corresponds
to the minimum area of the channel, may be situated at any point in the length of
the hull and may extend over a certain length. The bottom of the hull may merge
with the sides a in any suitable manner and may depend on the mode of pro-
pulsion. The lower profile of the sides a may vary according to the type of vessel
and they may be increased in depth by keels or extensions f (Figures 16, and 18)
so as to increase the section of the liquid vein confined.
In the type of vessel illustrated in Figures 16, 17, and 18 the external contour
of the hull which is constant, is formed of curves terminating in two keels f form-
ing the boundary of the water channel on either side, said channel being thus
limited solely by curved surfaces. The midship section is placed at one-third of
the length from the bow and the curve of the bottom has its maximum ordinate at
one-third the length from the bow but it is to be understood that the maximum
draught of water at the bottom of the water channel need not always correspond
to the midship section. The lines I, II, III, IV, V W L indicate the curves of
intersection of the various water levels.
Any means of propulsion may be adopted with this improved type of vessel such
as paddle wheels, screws, hydraulic propellers, etc., and where screws are employed
they would work with great efficiency if situated between the side walls a. The
vessel may also be steered in any suitable manner by the means ordinarily employed
with the aid of one or more rudders placed at any suitable point and either balanced
or not.
My invention may be applied to ordinary forms of vessels and I therefore reserve
the combination of my form of bottom with an ordinary vessel for the purpose, for
example, of improving certain conditions of navigability, reducing the diameter
of the turning circle, etc. The capacities limited by the walls a a having an
important relation to the total tonnage of the vessel, may be increased in certain
cases by giving the external water lines a curved form similar to the ordinary form
without altering the internal water lines. In this case the external form of the
vessel would no longer be constant throughout as in the preceding cases,
consequently the midship section may no longer correspond to the minimum
sectional area of the water channel.
It is to be understood that the hull may vary in form and dimensions and be
applied to all kinds of vessels and that the accessory arrangements may be modified
to suit the different applications.
T
J 1 l
سمل
Lunnam. 1000

page_text: to be performed, to be particularly described and ascertained in and by the
following statement;―
1
This invention relates to improvements in the hulls of vessels whereby the speed
will be largely augmented when the motive power is increased. With hulls of
ordinary form the motive power absorbed in propelling a vessel varies as the cube
of the speed and is moreover sensibly proportionate to the area of the immersed
midship section.
My invention has for object to enable an increased speed to be obtained with a
less amount of power than is required by the law above cited, that is to say so
that the motive power required shall increase in a lesser proportion than the cube
of the speed, this increase of speed being due to the lifting of the vessel which
reduces the area of the immersed midship section. The effect of thus raising the hulls
at very high speeds which is due as is known to the vertical reaction of the masses
of water set in motion by the hull has often been verified in the case of torpedo
boats for example, and the coefficient of utilization of the vessel has been thereby
increased, this coefficient being at a minimum which corresponds precisely to the
critical speed at which the lifting action commences. These facts are prefectly
well known but my invention consists in a special construction of the vessel's hull
which tends to cause the lifting of the vessel as soon as the speed increases, at
same time considerably reducing the area of the immersed midship section and
reducing to the utmost degree the critical speed, that is to say the speed at which
the lifting action commences.
According to this invention the hull presents at its lower part two walls merging
with the external form of the hull so as to form under the hull a sort of channel
of decreasing internal cross section which is constantly immersed and entirely
open at the underside and at the ends, the width diminishing from the bow end
to a given point in the length of the vessel in such manner that the vertical com
ponent due to the reactions of the masses of water set in movement by the reduc-
tion of the sectional area of the channel shall act on the bottom of the hull and
exert a lifting action. The decrease in the internal sectional area of the channel
may also be obtained by inclining the bottom of the vessel from bow to stern,
the width between the walls of said channel being either constant or diminishing
from bow to stern.
Reference is to be had to the drawings accompanying my Provisional Specifica-
tion which illustrates by way of example the construction of my improved hull.
Figures 1, 2, and 3 respectively represent a longitudinal section, underside plan,
and end elevation of a vessel. Figures 4, 5, and 6 respectively represent a plan,
longitudinal section, and end elevation of the immersed part of a hull whereof the
midship section is at mid-length. Figures 7 and 8 are transverse sections repre-
senting respectively the section at 3 (Figure 4) and the midship section M S.
Figures 9, 10, and 11 represent longitudinal sections of the immersed part of a
hull in three positions illustrating the lifting action; Figure 12 being a trans-
verse section shewing the diminution of area of the immersed midship section
when the vessel passes from the position shewn in Figure 9 to that of Figure 10.
Figures 13, 14, and 15 shew a modified form of vessel having the outer sides
inclined; Figure 13 being a longitudinal section, Figure 14 an underside plan, and
Figure 15 an end view shewing the forward sections F at one side and the aft
sections A at the other side of the vertical centre lines. Figures 16, 17, and 18
shew another modification of this type of vessel in which the external form, which
is constant, is constituted by curves terminating at two keels which limit the
water channel; Figure 16 being a longitudinal section, Figure 17 an underside
plan, and Figure 18 an end elevation shewing the forward and aft sections F
and A. The same letters of reference denote like parts in all the figures.
Referring to Figures 1, 2, 3, and 4, 5, 6, the hull has longitudinal side walls a
presenting at the inner side a longitudinally curved form such that the breadth of
free space left between the walls diminishes progressively from the bow end to a
given point in the length of the vessel and then again widens out to its original

page_text: dimensions at the stern, the sectional area of the channel thus formed by the two
sides a and bottom e of the hull thus varying continuously from a maximum to
a minimum amidships. The external water lines of the hull are absolutely recti-
linear lines and consequently the external form of the hull is constant and hence
all external displacement of masses of water by how pressure and the throwing up
of a swell will be avoided. The external water lines of the walls a are therefore
right lines whereas their internal water lines are curves.
The midship section is placed at the middle of the vessel and the longitudinal
section of the bottom is either a right line joined to the bow and stern by curves
or is a continuous curve. Comparing two transverse sections the one 3 F (Figure 7)
and the midship section MS (Figure 8) it will be seen that the cross-section of
the channel at e, Figure 8, is less than that at d. Figure 7.
In the progress of the vessel the water confined between the two walls a and
the bottom of the hull must pass from space d to space e as the walls a are per-
fectly rigid, the diminution in the sectional area from that shewn at d to that
shewn at e having the effect of exerting a pressure on the water so that the reaction
of the latter produces a vertical resultant which tends to lift the vessel. This
lifting action which increases with the speed diminishes the immersed midship
section and consequently the coefficient of utilization of the vessel increases. It
is to be understood, that the speed of the vessel must be sufficient to exceed the
speed of transmission of pressures in the water.
The horizontal components of the pressures upon the internal surfaces of the
walls a are symmetrical and mutually counteract each other. Under these con-
ditions the whole of the pressures upon the internal surfaces of the walls of the
water-way formed in the bottom of the hull have the effect of lifting the vessel.
In Figure 9 the vessel being stationary, the displacement is represented by h
and when it has exceeded its critical speed (which is very low compared with that
which corresponds to ordinary forms of vessels) the displacement will be reduced
to h¹ (Figure 10) and the diminution of area of the immersed midship section will
be represented by -- ; b (Figure 12) being the breadth of said midship section.
The displacement may even be reduced to zero, as shewn in Figure 11, in which
case only the portions a a remain immersed.
Hence the cause producing the lifting effect persists after action and the parts a a
remaining immersed the lifting gives rise to great stability. The stability is
very great since the breadth of the midship section may, owing to the form of
the vessel, be made very considerable.
This construction of hull is capable of being carried out in many forms while
the constant external form of the hull may also vary and may be that of a
trapezium, or rectangle with curved joining surfaces.
In the example shewn in Figures 18, 14. and 15 which as before represents
only the immersed portion of the hull the external lateral surfaces are inclined so
that the external form of the vessel which is constant presents the form of a
trapezium. I, II, III, IV, W L are the water lines up to the load water line:
1. 2, 3, 4, etc., are transverse vertical sections from amidships to the perpen-
diculars P, P and P1, P and MS the midship section which is at mid-length of
the vessel. The side walls a may only commence in rear of the bottom proper
of the hull or they may project beyond the superstructure both at the how and
stern.
The midship section which in the previous figures of the drawings corresponds
to the minimum area of the channel, may be situated at any point in the length of
the hull and may extend over a certain length. The bottom of the hull may merge
with the sides a in any suitable manner and may depend on the mode of pro-
pulsion. The lower profile of the sides a may vary according to the type of vessel
and they may be increased in depth by keels or extensions f (Figures 16 and 18)
so as to increase the section of the liquid vein confined.
In the type of vessel illustrated in Figures 16, 17 and 18 the external contour
of the hull which is constant is formed of curves terminating in two keels f form-

page_text: ing the boundary of the water channel on either side, said channel being thus
limited solely by curved surfaces. The midship section is placed at one-third of
the length from the bow and the curve of the bottom has its maximum ordinate also
at one-third the length from the bow, but it is to be understood, that the maximum
draught of water at the bottom of the water channel need not always correspond
to the midship section. The lines I, II, III, IV, V, W L indicate the curves of
intersection of the various water levels.
Any means of propulsion may be adopted with this improved type of vessel such
as paddle wheels, screws, hydraulic propellers, etc., and where screws are employed
The
they would work with great efficiency if situated between the side walls a.
The vessel may be steered in any suitable manner by the means ordinarily employed
with the aid of one or more rudders placed at any suitable point and either balanced
or not.
My invention may be applied to ordinary forms of vessels and I therefore reserve
the combination of my form of bottom with an ordinary vessel for the purpose, for
example, of improving certain conditions of navigability, reducing the diameter
of the turning circle, etc. The capacities limited by the walls a a having an
important relation to the total tonnage of the vessel, may be increased in certain
cases by giving the external water lines a curved form similar to the ordinary form
without altering the internal water lines. In this case the external form of the
vessel would no longer be constant throughout as in the preceding cases,
consequently the midship section may no longer correspond to the minimum
sectional area of the water channel.
It is to be understood that the hull may vary in form and dimensions and le
applied to all kinds of vessels and that the accessory arrangements may be modified
to suit the different applications.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
-
1. A vessel's hull having two lateral downward extensions merging externally
with the upper part of the hull and forming between them a water space or channel
beneath the bottom of decreasing sectional area which is constantly immersed and
open at bottom and at both ends, the sectional area of said water channel con-
tinually diminishing from bow to stern either by varying the width between the
walls the bottom of the vessel being flat-or by inclining the bottom from bow
to stern, the width between the walls being constant or diminishing from bow to
stern, in such manner that the vertical component due to the reactions of the
masses of water set in motion by the diminution of area of the channel shall act
on the bottom of the hull and thus produce a lifting movement of the same as and
for the purpose specified.
2. The application of this special form of bottom to the hulls of existing vessels
as specified.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.