IMPROVEMENTS IN APPLYING MEANS AND APPARATUS TO SHIPS AND VESSELS TO IMPROVE THEIR SPEED;
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
BOWES STEVENS, of Hoboken, in the County of Hudson, in the State of New
Jersey, in the United States of America, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of June,
One thousand eight hundred and forty-seven, in the tenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Francis Bowes Stevens, my exors, adiñiors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Francis Bowes Stevens,
my exors, admors, and assigns, or such others as I, the said Francis Bowes
Stevens, my exors, adiñiors, or assigns, should at any time agree with, and no
others, from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, and the Islands of
Guernsey, Jersey, Alderney, Sark, and Man, and in all Her said Majesty's
Colonies and Plantations abroad, the Invention of "IMPROVEMENTS IN APPLYING
MEANS AND APPARATUS TO SHIPS AND VESSELS TO IMPROVE THEIR SPEED;" partly
invented by myself, and partly communicated from Robert Livingston Stevens
a foreigner resident in the City, County, and State of New York, in the United
States of America, Engineer; in which said Letters Patent is contained a
proviso that I, the said Francis Bowes Stevens, shall cause a particular
description of the nature of the said Invention, and in what manner the same
is to be performed, by an instrument in writing under my hand and seal, to be

page_text: inrolled in Her said Majesty's High Court of Chancery within six calendar
months next and immediately after the date. of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Francis Bowes Stevens, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, reference being had
to the Drawings hereunto annexed, and to the figures and letters marked
thereon, that is to say :-
It has long been known that the resistance that hinders or impedes the
motion of vessels through the water arises from three causes, viz., the displace-
ment of the water by the vessel; the suction (as it is termed) at the stern,
produced by the motion of the vessel from the water; and, lastly, the friction
produced by the immersed surface of the vessel passing through the water. I
have not noticed the inertia of the mass to be propelled, as that when once
overcome is no longer a resistance, and the propelling machinery is always
constructed with a view to act regularly, and keep up the acquired momentum.
It has also long been known that the resistance, caused by the displacement,
as also that caused by the suction, could be reduced by making the vessel
sharper and of greater length, in proportion to the breadth, so that the water,
as the vessel, moves through it, could be displaced by the bow more easily, and
fill up at the stern more gradually. The friction produced by the immersed
surface of the vessel in passing through the water, has frequently been looked
upon as too trifling to be considered an element in calculating the resistance
to the motion of vessels,, and hence but, few efforts have been made to reduce
or. modify a resistance generally supposed to be much less than it actually is.
Although the experiments made in seventeen hundred and ninety-six, &c., by
Col. Beaufoy, upon the subject of the resistance, of fluids, have been considered.
as the, basis of all other investigations upon this subject, still his experiments
upon the subject of friction have not generally attracted that attention which
they deserve.. The amount of the, friction of water. (against a surface of wood
planed smooth, and painted) for each square foot of, surface immersed in the
water, and the general.law of its increase, were given. by him at a speed of from
two to ten miles per hour. These experiments on friction have been corro-
borated and continued by another series carefully..conducted by myself and
others on the Delaware and Raritan Canal,.,in New Jersey, with various
substances and qualities of surface, and at speeds of from one mile per hour to
upwards of forty. By these experiments I have proved that the resistance

page_text: due' to friction increases as the squares of the velocities, and I have found that
in the sharpest steam boats of the present day, that which has been frequently
deemed too inconsiderable to enter into a calculation is the largest element of
resistance: In vessels where the length is small in proportion to the breadth,
and where the angles of the bow and stern are obtuse; the resistance caused by
the friction of the water against the sidės and bottom of the vessel is very
small compared with the resistance caused by the displacement and the suction;
but in vessels where the length is very great in proportion to the breadtli, and
where the angles of the bow and stern are exceedingly sharp, the resistance
caused by the friction of the water is greater than the resistance caused by the
displacement and the suction: I have found that in a vessel two hundred and
twenty feet long, sixteen feet wide at the water line, moulded verry round, or,
as it is technically termed, "much cut up," drawing three feet water; and the
angle of the bow six degrees, that more than three quarters of the resistance to
the motion of this vessel was due to the friction of its immersed surface-
passing through the water. The means coinmonly used to diminish this:
friction have been to render that part of the surface of the vessel which passes"
through the water as smooth and even as possible. But I have become
satisfied by the experiments made with various substances and qualities of
surfaces, that even the most 'highly polished surfaces cause much friction. I
have been 'particular in stating the existance of this friction, its magnitude,
and the law of its increase, as it is the object of the principal part of my Inven-
tion for improving the speed of vessels, to diminish this friction, and this I do'
by the interposition of atmospheric air between the immersed surface of the.
vessel and the water, which I find greatly reduces the resistance due to this:
friction. The air is to be applied and supplied continuously while the vessel
is in motion; and over the whole or as large à portion of the immersed surface
as possible, and to be introduced by bellow's or other blowing apparatus,
through pipes, channel ways, or other conductors leading to apertures made in
the sides and bottom" of vessels, or by means of pipes or other conductors'
running over the sides 'and 'hows of vessels, and terminating in apertures or'
orifices distributed' over the immersed surface of vessels. It has been a maxim
among iaval architects and constructors that, to prevent as much as possible
the friction of the immersed 'surface of vessels against the water, it (the surface:
of vessels) must be made siiooth. But to: interpose air between the surface of
the vessel and the water, with the view to reduce friction, I depart from this.
maxim, and in departing. from it. I make over the entire immersed surface to
be supplied with air, certain irregularities consisting of projections and recesses;"
which produce 'two useful effects, viz,-first, they make the interposition of

page_text: the air more perfet by distributing it equally over the entire surface, and
by retaining it more perfectly, and for a longer time than would other-
wise be done; and, second, they produce, by a well-known physical law,
a suction in the apertures, tending to supply the air, by which less pres-
sure is required to supply the air to be interposed between the surface of
the vessel and the water. The most effectual way of making the projections
and recesses is, to put them on in manner somewhat resembling the scales
of a fish, or the shingles or flat tiles on the roof of a house, that is, a series of
inclined planes, forming a slight angle with the plane of the vessel's surface,
and arranged in the direction of the length of the vessel, so that the summit of
all the planes will be towards the stern, that when in motion, the water shall,
by the direction of the motion, pass from the tip of one scale to the tip of the
next succeeding one, the air on the inclined surface of the recesses formed by
the series of planes or scales having the effect to prevent the water from being
forced by the pressure of the column into the recesses. The air will thus lie
sheltered in a measure in these recesses, and the vessel will be in contact with
the water only at or near the tips of the scales, and will thus pass with a
stratum of air interposed between its surface and the water, and therefore
prevent that amount of friction which constitutes so large an element in the
resistance to the motion of vessels. The air is to be supplied to the recesses
formed by the series of inclined planes, through apertures at the lowest part of
each planc, and conducted there from channel ways, pipes, or other conductors,
by holes made in the vessel, or by branch pipes passing through the holes, so
that the air may issue at the lowest part of the planes, and pass along and
spread over the entire surface of the planes. The recesses formed between the
summits of the series of planes should be divided into cells by longitudinal
partitions, to prevent the escape of the air at the sides. The use of recesses
for the purpose above specified constitutes the second part of my Invention.
The air applied as above described, besides reducing the friction, will have the
effect to diminish the suction at the stern of the vessel, and I have found by
experiment, that if apertures are made at the stern large in size, and placed
closely together, and communicating with the atmosphere by tubes, that the
pressure of the atmosphere through the tubes will reduce the suction of
the vessel in its passage through the water. I place these apertures as closely
together as possible, without weakening too much the structure of the vessel,
or reducing in too great degree the buoyancy at the stern; the tubes or con-
ductors leading to the atmosphere must terminate at such distance from the
water as may be deemed requisite to prevent the water from overflowing them.
The use of these apertures at the stern to diminish the suction constitutes the

page_text: third part of my Invention. I will now proceed to describe, by reference to
Drawings, how the surface of a vessel is to be constructed with the view to
the application of my Invention.
In the accompanying Drawings, Figure 1 is a face view of a portion of the
surface of a vessel on my improved plan; Figure 2, a horizontal section
taken at the line X, X, of Figure 1; and Figure 3, a vertical section, taken at
the line Z, Z, of the same Figure. On the ordinary planking (a) of a vessel
constructed in any desired manner, which planking is here represented secured
to the timbers (6), are attached wedge-like projections (c), the outer surfaces
of which are inclined to the plane of the planking, with the summits of each
inclined plane towards the stern of the vessel. These wedge-like projections,
which I term the scales, because of their resemblance to the scales of a fish, over-
lap one another, leaving a space (d) under the after part of each scale, and the
spaces between the summits constitutes the recesses named in the preceding part
of this Specification. And these recesses are further divided into cells by longi-
tudinal partitions (e), to prevent the escape of the air at the sides. Holes (ƒ)
are made in the planking of the vessel, to which pipes (9) are fitted leading to
main pipes (h), or channel ways, or other main conductors for the supply of
air, and the holes (f), one or more for each cell, should be made under the
projecting or after part of each scale, so that the air in issuing from these holes
may diffuse itself, and cover the entire surface of each cell. Instead of making
the scales to overlap, their after ends may be perpendicular to the plane of the
vessel, as shewn in section, Figure 4; or, instead of this, the recesses may be
made of double and reversed inclined planes (i, k) as shown in section, Figure 5;
or the recesses may be formed between ribs, (1, 1,) the edges of which may be
rounded off, as shown in section, Figure 6. In these various modifications the
holes for the supply of air should be made in the most depressed part of the recesses.
It has not been deemed necessary to represent an entire vessel, as a portion is
deemed sufficient. I have used the inclined planes of various dimensions, and
have found the proper inclination to be of more importance than the length.
I have used them at inclinations of from one in twenty-five to one in sixty,
with a beneficial effect. These projections and recesses can be formed out of
the solid material of the vessel, or made separate and attached thereto. If it
were judged inexpedient to make the apertures through the bottom of a vessel,
tubes could be run over the sides, and introduced in the intervals between the
planking and the projections or scales, or the vessel may be built with two
thicknesses of planking, and the air introduced into an interval left between
them, this space being separated into divisions by ribs running from the bow
towards the stern. The air as above mentioned can be applied to a vessel's

page_text: I
But when
bottom without the intervention of these projections, but excepting at very low
velocities, and where the nature of the construction may render it necessary,
prefer the application of it by means of projections and recesses.
applied without the recesses, I should recommend that the apertures be
covered with plates, and the air be made to issue from under the after part of
these plates. In respect to the quantity of air required, I have, at the speed
of fifteen miles per liour, used one and a half cubic feet per minute for each
square foot of the immersed surface of the vessel, and have found it to produce
a beneficial effect, and, at a speed of twenty-eight miles per hour, I have used
five cubic feet of air per minute; for each square foot, with beneficial effect,
the scales being sixteen inches long, and having an inclination of one in sixty.
I have given no directions as to the blowing apparatus, by which the air must
be supplied, as this would of course vary according to circumstances, the
subject of forcing air under different pressures being well understood. Care
must be taken that the air be delivered at different pressures to the orifices
that are at different depths, or perpendicular distances from the surface of the
water, so that the greater portion of the air shall not escape from a few of the
apertures. In respect to the suction produced in the recesses, I would remark
that at a speed of twelve miles an hour, with scales one foot long, having an
inclination of one in twenty-five, the water was all drawn out of a tube six
inches deep, and this suction increased with the velocity, so that I found that
where the draught of water was one foot, and the speed thirty miles an hour,
sufficient air was drawn under the sides and bottom of the vessel to produce a
beneficial effect without the intervention of blowing apparatus. If it should
be judged inadvisable, from the want of sufficient power to force the air,
or from other causes, to supply the air over the whole immersed surface of the
vessel, the projectionis and recesses could be supplied to a portion only of the
surface. I have found in a scow-shaped vessel, or in a vessel where the sides
are inclined outwards, that in supplying the recesses with air at the bow and
stern, a large portion of those in the centre need not be supplied, and still a
beneficial effect produced, as the air introduced in the recesses at the bow is
carried from thence under the bottom of the vessel towards the stern, and
forced up by the surrounding water into the recesses not otherwiso supplied.
1 would observe that when there is no air in the recesses, I have always found
these projections and recesses detrimental, causing more resistance to the
motion of the vessel than a plain, surface would do. This method of dimi
nishing the friction is applicable to all vessels, but it is more peculiarly adapted
to vessels when the length is great in proportion to the breadth, where the
angles of the bow and stern are sharp, and where the draught of water is light,.

page_text: so that a sufficient supply of air can be readily obtained. By the method
above described, the friction of the water against the whole inummersed surface
and the suction at the stern is diminished, but the resistance cau-ed by the
displacement at the bow remains a fixed quantity, the way of reducing which
is by giving the vessel greater length in proportion to the breadth, and by
reducing the angle of the bow. This angle I recommend to be as sharp as
the construction of the vessel, and the purposes for which it is adapted, will
allow. It will be obvious that if any of 'the permanantly elastic gasses be
substituted in whole or in part for atinospheric air, that the same effect will
be produced. I am aware that it has been proposed to surround the bottom of
a vessel with ledges, making the bottom like an inverted box, and to introduce
air under a pressure into this box, for the purpose of raising it, to decrease the
draught of water; that air has also been forced from a vessel to act against
the water as a propelling agent. I am also aware that a Patent was granted in
England, in the year cighteen hundred and eighteen, to Thomas. Cockrane and
Alexander Galloway, which included, amongst other matters, the getting rid
of the gasses evolved from the combustion in the boiler furnaces of a steamer,
or, as they say,." to allow such gasses to escape for dissipation," by blowing
them under water, but without intention to diminish friction, and without any
description of means by which it could produce the effect; but what I claim
as my Invention is, supplying air to the immersed surface of a vessel through a
series of apertures or holes, to interpose a stratum of air between the immersed
surface of a vessel and the water, for the purpose of reducing the friction of
the water, as described.
I also clain as my Juvention the recesses on the immersed surface of the
vessel, as described, or any thing substantially the same, when combined with
the supplying of air for the purpose of distributing the air, and retaining it
more perfectly, and for a longer time, between the surface of the vessel and
the water; but it is to be understood that I do not claim these recesses in-
lependantly of their use and connection with the supply of air.
I also claim as my Invention the apertures made in the stern of a vessel,
and communicating with the atmosphere by pipes or other conductors, for the
urpose of diminishing that resistance produced by the motion of the vessel
rom the water, or (as it is cominonly called,) by the suction.
In witness whereof, I, tlie said Francis Bowes Stevens, have hereunto
set my hand and seal, this Thirteenth day of November, in the
our Lord One thousand eight hundred and forty-seven.
year of
FRANCIS BOWES (L.s.) STEVENS.

page_text: Taken and acknowledged by Thomas Bowes Stevens
(party hereto), at the City of New York, in the
United States of America, this 30th day of October
A.
This is the Specification referred to in the affidavit of Samuel Carpmael,
sworn before me, this 25 day of November 1847.
W THODEY SMITH.
Samuel Carpmael, of Old Square, Lincoln's Inn, in the County of Middlesex,
Gentleman, maketh oath, and saith that he is acquainted with the manner and
character of the handwriting of Anthony Barclay, Her Britannic Majesty's
Consul at New York, in the United States of America. And this deponent
further saith that the signature of "Anthy Barclay," set, subscribed, and
written in the margin of the Specification hereunto annexed, marked A, and
dated the Thirtieth day of October, now last past, and purporting to be
executed by Francis Bowes Stevens, of Hoboken, in the County of Hudson, in
the State of New Jersey, in the United States of America, Engineer, whereby
it is stated that the said Specification was acknowledged by him, the said
Francis Bowes Stevens, before the said Anthony Barclay, on the said Thirtieth
day of October, at New York, is of the proper handwriting of the said