CERTAIN IM- PROVEMENTS IN CONSTRUCTING AND PROPELLING SHIPS OR OTHER VESSELS
Year: 1849

page_text: DUGDALE AND BIRCH'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
DUGDALE and EDWARD BIRCH, both of Manchester, in the County of
Lancaster, Tool and Machine Makers, send greeting.
WHEREAS Her present most Excellent 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 Thirty-first day of May now last
past, did, for Herself, Her heirs and successors, give and grant unto us, the
said John Dugdale and Edward Birch, our exors, admors, and assigns, Her
especial license that we, the said John Dugdale and Edward Birch, our
exors, admors, and assigns, or such others as we, the said John Dugdale and
Edward Birch, our exors, admors, 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 also in
the Islands of Guernsey, Jersey, Alderney, Sark, and Man, and in all Her
Majesty's Colonies and Plantations abroad, our Invention of "CERTAIN IM-
PROVEMENTS IN CONSTRUCTING AND PROPELLING SHIPS OR OTHER VESSELS;" in
which said Letters Patent is contained a proviso obliging us, the said John
Dugdale and Edward Birch, by an instrument in writing under our hands
and seals, or under the hand and seal of one of us, particularly to describe and
ascertain the nature of our 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
Court of Chancery within six calendar months next and immediately after the
date of the said recited Letters Patent, as in and by the same Letters Patent,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
John Dugdale and Edward Birch, do hereby declare the nature of our said
Invention to consist, first, in so constructing ships and other vessels that a
channel or channels of peculiar forms for containing the screw propeller or
propellers is or are left in the lower part of their hull; secondly, in placing
two or more screw propellers of the same pitch, and of different diameters, on
the same shaft.
And in order that our Invention may be fully understood and readily
carried into effect, we will proceed to describo the Drawings hereunto an-
nexed, in the various Figures of which the same letters indicate similar parts.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents a side elevation of a vessel constructed according to our
improvements, and to which our improved propellers are applied; Fig. 2 is a
plan view of the vessel shewn in Fig. 1 with the propellers removed; Fig. 3
is a sectional elevation of Fig. 1; Fig. 4 is a side elevation of part of a vessel
constructed according to another modification of our improvements; and
Fig. 5 is a sectional elevation of Fig. 4.
In Figs. 1, 2, and 3, A is the channel placed in a line with the keel of the
vessel, and of sufficient dimensions to contain our improved propellers
marked B, B, and B³. The propellers are all mounted on the same shaft C,
and they are protected from injury by the guard D, which also answers the
purpose of a keel. The shaft C revolves near the stern in a bearing E, which
is bolted to a cross stay reaching from one side of the channel A to the other.
The other end of the shaft revolves in the bearing F, and it is connected to
the diagonal shaft G by the universal joint H. The shaft G is put in motion
by a steam engine or any suitable motive power driving the pinion G' fixed
near the top of the shaft G. It will be seen, on referring to Fig. 1, that the
propeller B is placed near the centre or midships of the vessel, and the pro-
peller B is placed near the stern, while the propeller B' is situated about
half-way between the two. The leading propeller B is less in diameter than
the centre one B', and this again is less in diameter than the stern one B.
They are, however, in the example shown on the Drawing all of the same
pitch, although it may be found advantageous to make the propellers of
different pitches. The channel A is wider near the stern than it is near the
midships, to suit the different diameters of the propellers; and it is bent
upwards near the bows of the vessel, to prevent the unnecessary displacement
of water by the advancing of the vessel; and on referring to Fig. 3 it will be
seen by the red lines that we place the centres of our propelling blades at
equal distances apart, to obtain a more equal application of the power.

page_text: In Figs. 4 and 5 we have shewn part of a vessel constructed with two
channels for containing our improved propellers; and in some cases, where it
-is necessary to have a large vessel in shallow water, we would apply three or
even more channels to contain the propellers, thereby obtaining a large
surface of the propelling power without increasing the draught of the
vessel.
Although we have shewn the channels in which the propellers revolve to
extend from the bows to the stern of the vessel, because we consider this to
be the most advantageous method of constructing ships or other vessels, wo
would remark that channels extending part of the length of the vessel might
be substituted in their stead, provided they be long enough to conduct the
water to the propeller; and we wish it to be distinctly understood that we do
not limit ourselves to the number of screw propellers placed upon one shaft,
nor to the relative diameters they bear to each other, as these may be varied
to suit the particular purpose for which they are intended; nor do we wish
to limit ourselves to the method of communicating motion to our screw pro-
pellers, as shown in Fig. 1, as they may be driven in various other ways.
Having thus described the nature of our Invention, and the manner in
which the same is to be performed, we do hereby declare that we claim, as of
our Invention in constructing ships and other vessels, the peculiar formed
channel or channels which are shown in the Drawings for containing the
propellers; and we also claim as of our Invention in propelling ships and
other vessels the placing of two or more screw propellers, each being of a
different diameter to the rest on the same shaft with each other. And such
our Invention being, to the best of our knowledge and belief, entirely
new within that part of Her said Majesty's United Kingdom of Great
Britain and Ireland called England, Her Dominion of Wales, and Town of
Berwick-upon-Tweed, and the Islands of Guernsey, Jersey, Alderney, Sark,
and Man, and in all Her Majesty's Colonies and Plantations abroad, we do
hereby declare this to be our Specification of the same, and that we do verily
believe this our said Specification doth comply in all respects, fully and without
reserve or disguise, with the proviso in the said herein-before in part recited
Letters Patent contained: wherefore, we do bereby claim to maintain
exclusive right and privilege to our said Invention.
In witness whereof, we, the said John Dugdale and Edward Birch, have
hereunto set our hands and seals, this Twenty-eighth day of November,
One thousand eight hundred and forty-nine.
JOHN (L.S.) DUGDALE.
EDWARD (L.S.) BIRCH.

page_text: AND BE IT REMEMBERED, that on the Twenty-eighth day of November,
in the year of our Lord 1849, the aforesaid John Dugdale and Edward
Birch 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 Twenty-ninth day of November, in the year of our Lord
One thousand eight hundred and forty-nine.