IMPROVEMENTS IN PROPELLING VESSELS
Year: 1841

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
NAPIER, of Millwall, in the County of Middlesex, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain bearing date at West-
minster, the Twenty-second day of March, in the fourth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said David
Napier, Her especial licence, full power, sole privilege and authority, that
I, the said David Napier, my exors, adñiors, and assigns, or such others as I,
the said David Napier, my exors, adññiors, and 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, my
Invention of "IMPROVEMENTS IN PROPELLING VESSELS;" in which said Letters
Patent is contained a proviso, that I, the said David Napier, shall cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be. 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
proviso, I, the said David Napier, do declare the nature of my Invention,
and the manner the same is to be performed, are particularly described and

page_text: ascertained in and by the following description thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thereon
(that is to say):
One part of my Invention consists in placing two wheels or propellers of equal
diameter at the stern of the vessel, the axes of both to be above the level of
the water, and one wheel farther aft than the other, so as to admit the blades
or float boards of one wheel to work nearly up to the axle of the other wheel,
and so that the float boards or blades of one wheel works clear of the blades
or floats of the other wheel, as is represented in Figures 1 and 2. I would
remark, I am aware that it has before been proposed to use two propellers at
the stern of a vessel, the blades or floats of each of which work in the spaces
of the other, in a somewhat similar manner to cogs of two cog wheels; but I
believe such mode has or will prove unsuccessful. My mode of employing two
wheels with oblique blades or floats in such manner that the one wheel will be
before the other, and not working one into the other, as is clearly shown in
Figures 1 and 2.
Another part of my Invention is represented in Figures 3 and 4, and
consists in connecting all the floats A to a metallic frame B, the weight of
which is sufficient to keep the floats in a nearly vertical position, the floats
being fixed on axles C, on the ends of which are cranks D, to which the
metallic frame is suspended, such frame B being unsupported by any eccentric
collar or bearing.
In witness whereof, I, the said David Napier, have hereunto set my hand
and seal, this Twenty-second day of September in the year of our
DAVID (L.S.) NAPIER.
AND BE IT REMEMBERED, that on the Twenty-second day of September,
in the year of our Lord 1841, the aforesaid David Napier came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and everything 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.
Inrolled the Twenty-second day of September, in the year of our Lord
One thousand eight hundred and forty-one.