AN IMPROVEMENT IN SADE DRADELIERS BARU PART OF REDUCING THE SLIP OF THE SAME
Year: 1869

page_text: LETTERS PATENT to Mathias Kolb, of the City and State of New
York, United States of America, but now residing in No. 13, Robert
Street, N.W., London, for the Invention of "AN IMPROVEMENT IN
SADE DRADELIERS BARU PART OF REDUCING THE SLIP OF THE SAME."
Sealed the 1st February 1870, and dated the 8th December 1869.
PROVISIONAL SPECIFICATION left by the said Mathias Kolb at the
Office of the Commissioners of Patents, with his Petition, on the
8th December 1869.
I, MATHIAS KOLB, of the City and State of New York, United
States of America, but now residing in No. 13, Robert Street, N.W.,
London, do hereby declare the nature of the said Invention for "AN
IMPROVEMENT IN SCREW PROPELLERS FOR THE PURPOSE OF REDUCING THE SLIP OP
THE SAME," to be as follows:-
I use in my propeller one or several screw threads which may be
attached to the propeller shaft, I prefer however to attach them to a
cylinder of a larger diameter than the shaft. The whole. I surround by
a case or cylinder open on both sides. I submerge my screw. but
partly, and consider it best to submerge it less than one half. (Screw

page_text: propellers which are encased and but partly submerged have been used
before.)
The object of my Invention is to reduce the slip of the screw by
hindering the water to move in any other direction than a direction
parallel to the line of the ship's motion. To attain this object I produce
the thread or threads of my screw to a much larger extent than has
heretofore been done in screw propellers, which are both encased and
but partly submerged. If I use a single screw thread I produce it to as
much more than a full turn as the screw is submerged. Therefore if the
screw is submerged one half I produce the single screw thread to one
turn and a half. If I use several screw threads I produce them to such
an extent that if a part equal to the extent to which the screw is sub-
merged was taken away from each screw thread, and all the remaining
sections of threads were joined together, the sum of these remaining
sections would be equal to one full turn. Therefore if the screw is
submerged one half, and I use two screw threads, I produce each of
them to one full turn. If I use three screw threads, the screw being
submerged one half, I produce each of them to five-sixth part of a turn,
and so further.
The object of my Invention may be partly attained by merely pro-
ducing the thread or threads of my screw to a large extent, the least
extent that, I consider of advantage being one quarter of a turn for each
thread, but the propeller will be the more perfect the nearer the extent
of its thread or threads approaches to the extent given in the above
rules.
My screw propeller may be applied to any part of the ship to which
screw propellers have been heretofore applied, it being only necessary
that the axis of the screw be arranged parallel to the line of the ship's
motion
SPECIFICATION in pursuance of the conditions of the Letters Patent, 3
filed by the said Mathias Kolb in the Great Seal Patent Office
on the 26th February 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MATHIAS
KOLB, of the City and State of New York, United States of America,
but now residing in No. 13, Robert Street, N.W., London, send 3
greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of December, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Mathias Kolb, Her special licence, that I,
the said Mathias Kolb, my executors, administrators, and assigns, or
such others as I, the said Mathias Kolb, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "AN IMPROVEMENT IN SCREW PROPELLERS
FOR THE PURPOSE OF REDUCING THE SLIP OF THE SAME," upon the condition
(amongst others) that I, the said Mathias Kolb, my executors or ad-
ministrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Mathias Kolb, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
I use in my propeller one or several screw threads which may be
attached to the propeller shaft, I prefer however to attach them to a
cylinder of a larger diameter than the shaft. The whole I surround by
a case or cylinder open on both sides. The inner as well as the outer
cylinder may be either revolving or stationary. If one or both are
revolving I connect it or them to the screw thread or threads; if one or
both are stationary I fit it or them as close to the screw thread or
threads as may be done without incurring friction. I prefer to make
the inner cylinder revolving and the outer case stationary. If the outer
case is stationary it is not exactly necessary that it should fit to the
screw thread or threads all around, but it should fit to it or them at least
so far as the water rises; its form may consequently be another than a
cylindrical. As it is only necessary that the screw is enclosed as high
as the water rises it would even be sufficient if the encasing only ex-

page_text: tented so far. I submerge my screw only so far that the shaft or inner
cylinder rise to such an extent above the water that the water does not
rise above them when the propeller is in motion. Screw propellers
which are encased and but partly submerged have been used heretofore.
The object of my Invention is to reduce the slip of the screw by
hindering the water to move in any other direction than a direction
parallel to the line of the ship's motion. To attain this object I produce
the thread or threads of my screw to a much larger extent than has
hertofore been done in screw propellers which are both encased and but
partly submerged. If I use a single screw thread I produce it to as
much more than a full turn as the screw is submerged. Therefore, if
the screw is submerged one half I produce the single screw thread to
one turn and a half. If I use several screw threads I produce them
to such an extent that if a part, equal to the extent to which the screw
is submerged, was taken away from each screw thread and all the
remaining sections of threads were joined together the sum of these
remaining sections would be equal to one full turn; therefore, if the
screw is submerged one half and I use two screw threads I produce cach
of them to one full turn. If I use three screw threads the screw being
submerged one half I produce each of them to five-sixth part of a turn,
and so forth. If the water in which the ship floats is agitated the im-
mersion of the screw will at times be larger than what it is in calm
water. I therefore in computing the extent of the screw threads add
about a foot to the immersion of the screw in calm water. As regards
the number of threads I consider it best to produce as many of them
as the submerged part of a vertical diameter of the screw is contained in
the whole diameter, omitting fractions. Therefore if the screw is sub-
merged about one half I use two threads, if submerged about one-third
I use three threads, if submerged about one-fourth I use four threads,
and so forth. The pitch admits of as great variation as the pitch of the
common screw propeller, I consider it, however, best to make it large;
in the annexed Drawings I have represented it as equal to one diameter
and a half of the screw.
The object of my Invention may be partly attained by merely pro-
ducing the thread or threads of my screw to a large extent, but the
propeller will be the more perfect the nearer the extent of its thread
or threads approaches to the extent given in the above rules.
My screw propeller may be applied to any part of the ship to which

page_text: screw propellers have heretofore been applied, it being only necessary
that the axis of the screw is arranged parallel to the line of the ship's
motion. The screw must, however, under all circumstances, protrude as
far above the level of the water as I have explained above.
In the annexed Drawings I have represented the screw as applied to
the stern of a vessel. The outer cylinder 6 is stationary while the inner
cylinder c is revolving with the screw threads. That this inner cylinder
may not act as an obstacle to the motion of the ship the lines of the
ship form for a small extent a continuation of this cylinder as has been
represented at d in the different Figures. To serve the same purpose,
at the other end of the cylinder a conical elongation e is attached to
the framework of the propeller. f represents the rudder of the ship.
The screw is submerged about a foot less than one half; each of its two
threads is produced to one full turn. In Fig. II. the outer cylinder
is represented as being partly broken away so as to expose the screw.
By referring to Fig. II. of my Drawings it will be seen that the
thread A, A¹, forms a perfect partition between the water in front and
behind of it. By the outer cylinder the water is also confined at the sides.
As the screw turns the water must therefore either rise or move in the
direction of the arrow. Rise it can only to a very small extent when
its weight will balance the pressure that caused it to rise. The water
has consequently no other egress than in the direction of the arrow,
that is, in a direction parallel to the line of the ship's motion. Before
the screw has turned so far that the end A¹ of the thread A, A' is sub-
merged in the water, the end B¹ of the thread B, B', has emerged from
the water and the thread B, B', has so formed a new partition. In
this manner there will always be perfect partition, and the water can
therefore never move in another direction than a direction parallel to
the line of the ship's motion. The same applies to any other number
of threads if they are produced to the extent given in the rules.
It will at once be perceived that if the thread or threads were produced
to a smaller extent than that given in the rules, the partition between
the water would not always be perfect, the water could, therefore, at
times assume a lateral motion, and the object of my Invention would
only be partly attained. By making the threads larger the efficiency of
the propeller would also be reduced since the frictional surface would
be enlarged without deriving any advantage of the enlargement.

page_text: Having completed my description, I wish to state that I do not
claim screw propellers which are encased, nor such which are but partly
submerged, nor such which are both encased and but partly submerged;
but I claim, the mode of producing the thread or threads of screw
propellers, which are both encased and but partly submerged to an
extent within the limits of one-third and one and three-quarters of a
turn; and I wish it to be distinctly understood that the propeller which
I claim unites these three characteristics,-1, it must be encased as
described; 2, it must only be partly submerged as described; and,
3, its thread or threads must be produced to an extent within the limits
of one-third and one and three-quarters of a turn.
In witness whereof, I, the said Mathias Kolb, have heretofore set
my hand and seal, this Twenty-sixth day of February, in the
year of our Lord Eighteen hundred and seventy.
(L.s.) MATHIAS KOLB.