IMPROVEMENTS IN PROPELLING VESSELS
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, We, JAMES
LOWE, late of No. 4, Charlotte Place, Upper Grange Road, Bermondsey, in
the County of Surrey, but now of No. 9, Union Place, East Greenwich, in
the County of Kent, Mechanist, and THOMAS EYRE WYCHE, of No. 13, George
Street, Mansion House, in the City of London, Gentleman, send greeting.
WHEREAS Her present Majesty Queen Victoria, by Her Letters Patent
under the Great Seal of the United Kingdom of Great Britain and Ireland,
bearing date at Westminster, the Nineteenth day of August, in the sixteenth
year of Her reign, gave and granted unto us, the said James Lowe and
Thomas Eyre Wyche, our exors, adñiors, and assigns, Her especial licence,
full power, sole privilege and authority, that we, the said James Lowe and
Thomas Eyre Wyche, our exors, adñiors, and assigns, should and lawfully
might, during the term of years therein mentioned, make use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and
also in the Islands of Guernsey, Jersey, Alderney, Sark, and Man, and in
all Her said Majesty's Colonies and Plantations abroad, our Invention of
"IMPROVEMENTS IN PROPELLING VESSELS;" in which said Letters Patent there
is contained a proviso that if we, the said James Lowe and Thomas Eyre
Wyche, shall not particularly describe and ascertain the nature of our said
Invention, and in what manner the same is to be performed, by an instrument
in writing under our hands and seals, and cause the same to be enrolled in
Her said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said Letters Patent, then those Letters
Patent, and all liberties and advantages whatsoever thereby granted, should
utterly cease, determine, and become void, as in and by the same will more
fully appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
James Lowe and Thomas Eyre Wyche, do hereby declare that the nature of
our said Invention, and the manner in which the same is to be performed,
are particularly described and ascertained, reference being also had to the
Figures in the Drawing hereunto annexed, as follows (that is to say):-
Our Invention consists in the construction and application of an instrument
for propelling vessels free from many of the defects of the screw propeller now
in use, and producing a greater effect in the propulsion of vessels than any
other propeller with which we are acquainted. The propellers now generally
in use are blades, being sections or portions of a screw, either of a uniform or
increasing pitch, affixed to an axis below the water-line of the vessel, or cast
in solid therewith, as described in-the-Specification of Letters Patent granted
to me, James Lowe, on the Twenty-fourth day of March, in the year of our
Lord One thousand eight hundred and thirty-eight, and which have now
expired. Such propellers are subject to several defects.. First, there is con-
siderable slip," as it is technically termed; secondly, there is a churning of the
water at the lower part of the blade next the axis; thirdly, there is a vibration
or tremulous motion in the ship during the rotation of the blades; fourthly,
there exists some resistance to complete freedom of action in the said propellers
at the outer edge of the blade, and at the axis or boss of the said propellers.
"
Now, our Invention relates, first, to the surfaces of the blades; secondly, to
the position of the blades in reference to the axis of motion; thirdly, to the
shape or configuration of the boss in relation thereto.
In the ordinary screw propeller, to take for illustration the well-known
instance of a propeller with two blades, each blade has a curved surface,
which, if continued, would form a portion of such a screw as would be gene-
rated by winding a plane round a cylindrical or conical axis, the blades being
cast solid with or affixed to a cylindrical boss on the axis, the lines of junction
of the blades making nearly the same angles with the axis of motion; and
the blades are so set with reference to each other that the outer edges of the
two opposite blades may, for all practical purposes, be regarded as on the same
line. In the propeller constructed according to our Invention of two blades
the surfaces of the blades are no portion of a screw, the lines of junction with
the boss and the surfaces of the blades are in planes crossing each other, and
the outer edges are not in a line with each other, but the central portions of
each blade are in the same line, and a straight line may be drawn passing
through each blade, and the centre of the boss or axis when the blades are
opposite and transverse to each other.
We will now explain in detail, by reference to the Figures in the accom-
panving Drawing, the peculiarity of the construction of our propeller.

page_text: Fig. 1 is a view or elevation of our propeller with two blades on an oval
boss, as seen from opposite the end of the axis of rotation.
Fig. 2 is a view of the same propeller as seen looking down from above the
outer edge c, a, e, of the blade.
Fig. 3 is a view or elevation of the same propeller as seen sideways of the
boss or axis of rotation. The lines O, a, O, y, O,, in the Figures represent
geometrical axes or lines in spaces passing through the centre of the propeller
to the planes passing through which it may be convenient to refer the
propeller.
Fig. 4 is a sectional plan of the boss taken horizontally or in a plane at
right angles to the plane of the paper, that is, in the plane of a, y, through
the centre of the axis, as on the line O, y, in Fig. 3. The lines g, h, and i, j,
shew the intersections of the blades with the boss, or more properly the lines
in which the central planes of the parts next the boss of the upper and lower
blades would intersect if produced.
Fig. 5 is a view of a propeller with four blades on an oval boss seen from
opposite the end of the axis.
Fig. 6 is a plan shewing the direction of the junction lines and of the outer
edge of the blades on the boss.
Fig. 7 is a view in perspective with two blades as seen obliquely.
In the propeller above described the two halves of cach blade are a counter-
part of each other if reversed, and the upper is a counterpart of the lower
blade set on lines crossing each other at angles with the axis varying with the
velocity at which the propeller is to be driven, and the vessel to which it is to
be applied, and the power of its engines, as is now well understood in the
construction and application of the ordinary screw propellers. The surfaces of
the blades are curved from the base or diagonal line on the boss and the
middle line of the face towards the outer corners, so as to present a curvature
on each half of each blade. The result of this peculiar conformation of the
surface is, that if a straight edge be laid on the line c, d, it will rest on
the points c and d. The blade will be concave under such edge; and if a
straight edge be laid on the line e, f, it will rest on a convex elevation,
the blade falling away towards the points e and f, or being convex to such
straight edge. Also the portions of the blade on either side of the middle
line a, b, are bent or twisted, so that the extreme portion of the blade, as on
the line c, e, does not deviate sensibly from a plane surface. The propeller so
constructed may be driven either way with equal velocity. We chamfer off
the outer edges of the blades so as to form a species of "cutwater" for the
direct and reverse action, and to diminish the resistance on the edges of the
blades. A cylindrical or spherical boss may be used, but we find the oval

page_text: form of boss facilitates the motion of the blade and the passage of the water,
so that the churning action and the vibration of the ordinary screw propeller
do not exist to any appreciable extent in our propeller. In the description
above given the blades are supposed to be cast with or affixed to the axis, so
as to be exactly opposite each other; for instance, so that there should be one
straight central line through the opposite blades, and that the middle line on
the face of cach opposite blade should be in the same straight line. This
theoretical accuracy may be difficult to attain in practice; and, provided the
blades are set so as to balance each other, a slight departure from the central
lines will not destroy the beneficial effects resulting from the arrangements
herein described. It will also be obvious that three of our blades, with concave
and convex surfaces or twisted planes, as above described, may be employed,
arranged in such manner as to balance each other, their planes and central
lines intersecting the axis of the boss. The precise dimensions of the propeller
will depend on the vessel and the power of the engines, and the required
speed, all which is now well understood by persons conversant with the screw
propellers as at present in use.
In order to afford the fullest information in our power, we will proceed to
describe the dimensions of two of our propellers, which for distinction we
will call the Miskin and the Argus, which have been used and applied,
and found superior to the screw propellers previously in use under similar
circumstances:-

page_text: Having now described the nature of our Invention, and in what manner the
same is to be performed, we hereby declare that we claim as our Invention a
propeller with two or more blades, concave and convex on each surface, set on
an oval boss, or cast in solid therewith, in lines or planes, as above described.
In witness whereof, we have hereunto set our hands and seals, this
Eighteenth day of February, in the year of our Lord One thousand
eight hundred and fifty-three.
AND BE IT REMEMBERED, that on the Eighteenth day of February,
in the year of our Lord 1853, the aforesaid James Lowe and Thomas Eyre
Wyche came before our said Lady the Queen in Her Chancery, and acknow-
ledged the Specification aforesaid, and all and every thing therein contained
and specified, in form above written. And also the Specification aforesaid was
stamped according to the tenor of the Statute made for that purpose.
Enrolled the Eighteenth day of February, in the year of our Lord