Improvements in or relating to the Surfaces of Bodies Moving in Water.
Year: 1899

page_text: Date of Application, 28th June, 1899
Complete Specification Left, 5th Mar., 1900-Accepted, 19th May, 1900
PROVISIONAL DIECIFICATION.
Improvements in or relating to the Surfaces of Bodies Moving in
Water.
I, JAMES O'HARA, of Victoria Club, Huron Street, City of Toronto, County of
York, Province of Ontario, Dominion of Canada, Gentleman, do hereby declare
the nature of this invention to be as follows:-
My invention relates to coverings for bodies impelled through water and has
for its objects to lessen the attraction between the body and the water and the
cohesion of the latter whereby the body impelled is more effectively cleared of
what is known as dead water thus materially reducing the resistance caused by
such water and utilizing to a fuller extent the impelling force wasted in over-
coming that resistance.
Ships' skins, the surfaces of propeller blades and similar marine bodies, as now
constructed, are made as smooth and even as possible with a view to offering
the least possible resistance. With this construction it is found that the vessels
or other bodies cannot clear themselves of what is generally called dead water
but will, during their progress, carry with them at the expense of the propelling
power a large amount of the surrounding water. The dead water is not only
dragged along by the vessel or similar structure but is also pushed in front thereof
in a large body which will fail to divide until heaped forward of the bows of
the vessel or like projections or similar structures. This pushing and dragging
of the water is caused by its cohesion. The result of this is that a large part
of the propelling power must be expended in overcoming the resistance of this
pushing and dragging water. To obviate this difficulty as much as possible,
vessels are tapered, not only at the bow but from midships to stern making the
lines forward and aft as fine as possible, whereby the vessel is enabled to divide
the water more cleanly at the bows and to clear itself of the surrounding water
which is being dragged after it. But even with this construction, however fine
the lines may be, the difficulty is far from being removed.
If the
The same difficulty attends the driving of the blades of the propeller screw
through the water. In order to propel the vessel the blades must continually
pass through the water, taking in new water and forcing it to the rear.
screw is driven too fast it will carry round with it the whole body of water in
which it is moving, which will prevent its taking in new water or making much
forward movement. This condition is due to the same cause of cohesion. If
the blades could continually pass through the water and not drag it with them, the
faster the screw revolved the greater would be the propelling force obtained.
My invention is intended to meet or remove or modify these difficulties and
enable a ship to clear itself of dead water, and also to enable the screw blades,
and similar bodies better to pass through the water and free themselves of it.
I have discovered that the cohesion of the water may be counteracted and
neutralized by producing vibration in a very thin stratum of water next to the
object so passing through the water.
It is obvious that with a perfectly smooth and even surface below the water-

page_text: To
line there will be no vibration and therefore the cohesion of the water is allowed
to act with greater force, and hence the more difficult it is to propel the vessel.
It does not follow, however, that roughness or uneveness without design will
facilitate the movement of any solid body when passing through water.
accomplish this result, I make the surface of the moving body imbricated or
shingle-like, the narts corresponding to shingles being of the form and arranged
on and attached to the body as hereinafter described.
When the imbricated surface is applied to a ship's hull, the water-shed is from
bow to stern, when applied to propeller blades it is in the opposite direction to
the forward movement of the blades.
My invention is illustrated in the accompanying drawings which show the
application of the invention to the hull of a ship and in which Fig. 1 is a side
view in elevation of the ship's hull, Fig. 2 a sectional plan of three of the
imbricated segments and Fig. 3 a perspective view of one of the imbricated
segments.
Referring to the drawings A is one of the pieces corresponding to house shingles
which is fastened to the hull with the thin end toward the bow. The segments
are either secured to the hull just as shingles are put on a roof, so as to overlap
and present a series of protrusions and depressions, or they may be rolled or
moulded or otherwise formed on the plates of iron, steel, wood or other material,
which cover the sides; in either case forming an uneven surface which will pro-
duce a vibrating stratum of water around the vessel. It is not necessary that each
imbricated segment should be a whole plate. There may be many imbricated
segments on one plate, integral therewith. The rear edges of each segment are
beveled or reduced in rolling or moulding.
The segments are arranged in rows B so that they break joint, the rounded
end of one segment being opposite the junction of two adjoining segments of the
succeeding row.
In the case of a vessel the length of a segment should be from one inch to
two feet, the width of about the same dimensions, according to the size or tonnage
of the vessel and the imbrication should show at the after end a drop or fall of from
one quarter of an inch to two inches according to the length of the segment. The
dimensions of the propeller blades should vary in accordance with the above.
It is obvious that any suitable arrangement of the overlapping portions or
segments forming an imbricated surface adapted to produce a vibrating stratum
adjacent to the moving body, may be applied to the surface of the body without
departing from the principle of my invention.
From the foregoing description it will be seen that my invention will create
a vibration of the water surrounding the vessel or other body that will tend to
break up the cohesion of the water and will enable the body to pass through the
water without carrying the usual burden of dead water.
Dated thi th
1 1000
JAMES O'HARA.
COMPLETE SPECIFICATION..
Improvements in or relating to the Surfaces of Bodies Moving in
Water.
I. JAMES O'HARA, of Victoria Club, Huron Street, City of Toronto, County of
York, Province of Ontario, Dominion of Canada, Gentleman, do hereby declare
the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by, the following statement:
My invention relates to coverings for bodies impelled through water and has

page_text: for its objects to lessen the attraction between the body and the water and the
cohesion of the latter whereby the body impelled is more effectively cleared of
what is known as dead water thus materially reducing the resistance caused by
such water and utilizing to a fuller extent the impelling force wasted in over-
coming that resistance.
Ship's skins, the surfaces of propeller blades and similar marine bodies, as now
constructed, are made as smooth and even as possible with a view to offering
the least possible resistance. With this construction it is found that the vessels
or other bodies cannot clear themselves of what is generally called dead water
but will, during their progress, carry with them at the expense of the propelling
The dead water is not only
power a large amount of the surounding water.
dragged along by the vessel or similar structure but is also pushed in front thereof
in a large body which will fail to divide until heaped forward of the bows of
This pushing and dragging
the vessel or like projections of similar structures.
of the water is caused by its cohesion. The result of this is that a large part
of the propelling power must be expended in overcoming the resistance of this
To obviate this difficulty as much as possible
pushing and dragging water.
vessels are tapered, not only at the bow but from midships to stern making the
lines forward and aft as fine as possible, whereby the vessel is enabled to divide
more cleanly at the bows and to clear itself of the surrounding water
which is being dragged after it. But even with this construction, however fine
the lines may be, the difficulty is far from being removed.
The same difficulty attends the driving of the blades of the propeller screw
through the water. In order to the propel the vessel the blades must continually
If the
pass through the water, taking in new water and forcing it to the rear.
screw is driven too fast it will carry round with it the whole body of water in
which it is moving, which will prevent its taking in new water or making much
forward movement. This condition is due to the same cause of cohesion. If
the blades could continually pass through the water and not drag it with them, the
faster the screw revolved the greater would be the propelling force obtained.
My invention is intended to meet or remove or modify these difficulties and
enable a ship to clear itself of dead water, and also to enable the screw blades,
and similar bodies better to pass through the water and free themselves of it.
I have discovered that the cohesion of the water may be counteracted and
neutralized by producing vibration in a very thin stratum of water next to the
object so passing through the water.
To
it is obvious that with perfectly smooth and even surfaces below the water-
line there will be no vibration and therefore the cohesion of the water is allowed
to act with greater force, and hence the more difficult it is to propel the vessel.
0It does not follow, however, that roughness or uneveness without design will
facilitate the movement of any solid body when passing through water.
accomplish this result, I make the surface of the moving body imbricated or
shingle-like, or like the scales of a fish, the parts corresponding to shingles being
of the form and arranged on and attached to the body as hereinafter described.
When the imbricated surface is applied to a ship's hull, the water-shed is from
bow to stern, when applied to propeller blades it is in the opposite direction to
the forward movement of the blades.
5
°
My invention is illustrated in the drawings filed with my Provisional Specifica-
tion which show the application of the invention to the hull of a ship and in
50 which Fig. 1 is a side view in elevation of the ship's hull, Fig. 2 a cross section of
several segments and Fig. 3, a detail plan of one of the imbricated segments.
Referring to the drawings A is one of the pieces corresponding to house shingles
which is fastened to the hull with the thin end toward the bow. The segments
are either secured to the hull just as shingles are put on a roof, so as to overlap
55 and present a series of protrusions and depressions, or they may be rolled or
moulded or otherwise formed on the plates of iron, steel, wood or other material,
which cover the sides; in either case forming an uneven surface which will pro-

page_text: duce a vibrating stratum of water around the vessel. It is not necessary that each
seguient should be a whole plate. There may be many imbricated segments on
one plate, integral therewith. The rear edges a of each segment are beveled
or reduced in rolling or moulding.
The segments are arranged in rows B so that they break joint, the rounded
end of one segment being opposite the two adjoining segments of the succeeding
row.
In the case of a vessel the length of a segment should be from one inch to
two feet, the width of about the same dimensions, according to the size or tonnage
of the vessel and the imbrication should show at the after end a drop or fall of from
one quarter of an inch to two inches according to the length of the segment. The
dimensions of the propeller blades should vary in accordance with the above.
It is obvious that any suitable arrangement of the overlapping portions or
segments forming an imbricated surface adapted to produce a vibrating stratum
adjacent to the moving body, may be applied to the surface of the body without
departing from the principle of my invention. Instead of having the segments
overlap they may be arranged separately and in rows but with raised projecting
surfaces at the same angles as that produced by the overlapping of the segments.
Such an arrangement produces a formation like that of the scales of a tarpon,
and gives the vibrating stratum of water adjacent the vessel as in the case of
the overlapping arrangement.
From the foregoing description it will be seen that my invention will create
a vibration of the water surrounding the vessel or other body that will tend to
break up the cohesion of the water and will enable the body to pass through the
water without carrying the usual burden of dead water.
Having now particularly described and ascertained the nature of this said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
-
1. A covering for bodies impelled through water consisting of segments aranged
in rows and projecting outwardly from the surface of the body with their thin
ends in the direction of the movement of the body, substantially 'as described.
2. A covering for bodies impelled through water consisting of an imbricated
surface, the imbricated portions thereof arranged with the overlapped or thin
edges toward the direction of the forward movement of the impelled body, sub-
stantially as described.
3. A covering for bodies impelled through water consisting of imbricated seg-
ments having their thin ends pointing in the direction of the forward movement
of the body, and arranged in rows in which the segments of each row break joint
with segments of the succeeding row, substantially as described.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant,
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant,