CERTAIN IMPROVEMENTS IN THE MACHINERY FOR PROPELLING VESSELS BY STEAM, BY WHICH THEIR SPEED WILL BE MUCH ACCELERATED WITH A DIMINISHED POWER, AND WITH A DIMINISHED ACTION IN THE WATER
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
EDOUARD FRAISSINET, of Covent Garden Square, in the City of Westminster,
Gentleman, send greeting.
'
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-sixth day of July, in the second year of Her reign,
and in the year of our Lord One thousand eight hundred and thirty-eight
did for Herself, Her heirs and successors, give and grant unto me, the said
Frederic Edouard Fraissinet, Her. especial license, full power, sole privilege
and authority, that I, the said Frederic Edouard Fraissinet, my executors,
administrators, and assigns, or such others as I, the said Frederic Edouard
Fraissinet, my executors, administrators, 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 mentioned, should and lawfully might make, use, exercise, and
vend, within England; Wales, and the Town of Berwick-upon-Tweed, an
Invention of "CERTAIN IMPROVEMENTS IN THE MACHINERY FOR PROPELLING VESSELS
BY STEAM, BY WHICH THEIR SPEED WILL BE MUCH ACCELERATED WITH A DIMINISHED
POWER, AND WITH A DIMINISHED ACTION IN THE WATER," being a communication
from a foreigner residing abroad; in which said Letters Patent is contained
a proviso obliging me, the said Frederic Edouard Fraissinet, by an instru
ment in writing under my hand and seal, particularly to describe and ascer-
tain the nature of the said Invention, and in what manner the same is to
be performed, and to cause the same to be enrolled in Her Majesty's High

page_text: 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
Frederic Edouard Fraissinet, do hereby declare that the nature of the said
Invention, and the manner in which the same is to be performed, is parti-
cularly described and ascertained in and by the following description thereof,
reference being had to the Drawings hereunto annexed, and to the letters and
figures marked thereon (that is to say):-
This Invention consists in the construction of a rotary propeller, in the form
of a screw, and its application to the purpose of propelling ships, boats, and
other vessels upon the water. This improved propeller is somewhat similar in
construction to the Archimedes screw, the application of which to a similar
purpose has already been attempted, but without entire success.
The pre-
viously proposed construction, however, differs from the present Invention in
some very essential particulars, which I shall now proceed to point out. Upon
examining the thread of an Archimedes screw, constructed upon the true prin-
ciples, it will be found that the thread or surface, from the commencement to
the end, consists of an uniform helical curve, the thread of the screw being
álways perpendicular to the axis. Now the Inventor has discovered that helical
surfaces placed exactly parallel to each other, (as is the case in the Archimedes
screw,) when employed in place of paddle wheels for propelling boats or other
vessels, is liable to as great an inconvenience as the common paddle wheel,
because, in order to obtain a continued pressure against the water, the thread
of the screw ought to increase in its obliquity in a greater proportion than the
ship advances. To obviate therefore the inconvenience of the parallel Archi-
medes screw propeller, the Inventor has substituted a parabolic curve, of which
he makes the thread of the screws to consist, instead of the parallel curve; the
inclination of this parabolic curve must be such, that the anterior extremity of
the thread may enter the water without creating a shock, which would have
the effect of counteracting the power of the engine, and the progressive increase
of inclination of the thread as the screw revolves must be such, that the
whole of its surface, from the commencement to the end of the thread, will
continue pressing against the water, and also receive from the water that con-
tinued resistance which is necessary to cause the vessel to advance. In the
Archimedes screw also, the helical surface which forms the thread is joined to
the axle or central shaft, so as to form one entire helical surface, extending
from the axle to the outer edge of the thread; but the present Inventor has

page_text: discovered that the propeller will work with greater facility if he leaves a vacant
space between the central shaft and the thread or propelling surface of the
screw, so that the thread is only attached to the shaft by a number of supports,
thereby allowing the water to flow out near the axle after it has exerted its
resistance against the surface of the thread. It may here be observed, that in
all the schemes at present known for propelling vessels, and in which the
Archimedes screw is employed as a mover, the thread has been made to consist
of too great a number of spirals. In the present Invention only one or two
spirals are used, as a greater number would not only be useless, but really dis-
advantageous, by the great friction that would be occasioned from the rapid
rotation of the propeller against the water. This is a fact that has not hitherto
been noticed. The distance between the two extremities of the spiral is nearly
equal to the external diameter of the screw; and the diameter will of course
depend upon the size of the ship or other vessel. For example, a ship of one
hundred and twenty feet in length, and thirteen feet in breadth, the screws
to be adapted to the two sides should be about five feet in diameter.
I will now proceed to describe the Drawing hereunto annexed, in which I
have shewn the improved propeller adapted to both sides of a vessel. Fig. 1
is a side elevation of a vessel, and Fig. 2, a plan view, with the propellers
properly mounted in connection with gear work, intended to be driven by a
steam engine in the ordinary manner; Fig. 3 represents a front view of one of
the screw propellers. a is the main shaft; b, b, the thread or propelling surface
which acts upon the water; c, c, c, c, are arms, made of wood, iron, or other
suitable material, supporting the thread of the screw; d, d, d, d shows the
vacant space between the thread and the central shaft of the screw, intended to
allow the water to flow through to prevent the screw from choking. In con-
clusion, I would wish it to be understood, that I claim the right of placing the
screw above described in whatever situation I may deem desirable, according
to the circumstances; for instance, I may either partially or totally immerse it
in the water, or I may place it either behind, before, or on cach side of the
vessel. For vessels that are intended for navigating the sea, it is preferable
totally to immerse the propeller in the water; the speed of the vessel will of
course depend upon the rapidity with which the screw is made to revolve.
In witness whereof, I, the said Frederic Edouard Fraissinet, have here-
unto set my hand and seal, this Twenty-fifth day of January, in the
year of our Lord One thousand eight hundred and thirty-nine.
FREDERIC EDOUARD (L.S.) FRAISSINET.

page_text: AND BE IT REMEMBERED, that on the Twenty-fifth day of January, in
the second year of the reign of Her Majesty Queen Victoria, the said Frederic
Edouard Fraissinet came before our said Lady the Queen in Her Chancery;
and acknowledged the instrument 'aforesaid, and all 'and' every thing therein
contained "and specified; in form above written. And also the instrument
aforesaid was stamped according to the tenor of 'the Statute made in the
fifty-fifth year of the reign of His late Majesty King George the Third. >
Inrolled the Twenty-sixth day of January, One thousand eight hundred
and thirty-nine.