Method and Construction for Reducing Friction Between the Surfaces of Ships and the Water.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Method and Construction for Reducing Friction Between the Surfaces
of Ships and the Water.
I, EDUARD LINDEMANN, of Schellingstrasse 41/1, Munich, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:-
By the movement of ships through the water an essential resistance is caused
by the friction which hinders the fast movement of the same and the result is a
diminution of speed caused by the friction of the ship's bow with the water. The
greater the speed the greater will be the resistance. By the diminution of the
friction surface between the exterior of the ship and the water the friction and
resistance would be lessened. The following method and the hereinafter described
arrangement are such that the amount of friction is lessened by providing between
the outside of the vessel and the water a thin layer of air. As the skin of fishes
is provided with scales the slippery nature of the slime of the same lessens the
friction between the fish and the water, in a like manner if the ship's bows were
covered with metal plates having spaces between the friction between the ship's
bows and the water would be lessened by air escaping therefrom. For this pur-
pose so much of the surface of the ship as lies under water is surrounded with a
thin air layer in a similar manner as the skin of fishes is covered with slime.
This air layer is automatically formed by the speed of movement of the ship
without mechanical means or compressed air.
The scale formed metal plates lying one upon the other form pockets, over
which by the movement of the ship the water glides so as to draw air out of the
pockets. This produces an exterior air layer acting against the friction, lessen-
ing the effect of the friction and increasing the speed. The greater the speed in
a like manner will the air space be increas d, proportionally reducing the resist-
ence.
On the exterior of the vessel narrow vertical overlapping plates are arranged
which extend from the edge to the keel of the vessel. Each plate overlaps its
neighbour in a similar manner to the scales of a fish. Between each of these plates
a pocket is formed which from their upper part to their middle is closed and of
which the lower part coming underneath the water line is open. At the keel line
the pockets are closed. The plates are arranged so that between each of them is
a narrow opening or slit under the water line. The lower part of these plate.
pockets conforms to the outline of the ship and fits closely thereto, but the upper
part is separated from the same so that an air chamber is formed. This air
chamber is open at the bow of the ship and closed at the stern, so that by the
forward movement of the ship air is drawn into the air chamber and passes into
all the pockets. The air chamber is connected at its lower part to the pockets so
that the air by reason of the pressure will pass into the pockets rushing out of
the same through their narrow openings. When the ship is still the pockets
below the water are filled with water. The water will not remain in the pockets
so long as the speed of the ship is greater in proportion to the flow of the water

page_text: which is governed by the water pressure and the draft of the ship. Thus by the
action of the moving water air is drawn out through the openings of the pockets.
This suction of the air by the water is assisted by the entrance of the air into
the air chambers open at the bow of the ship. It results therefore that by the
forward movement of the ship the water in the pockets is formed out through the
narrow openings or slits of the same by the air pressure in the air chamber. The
slit openings of the pockets are connected together at suitable points, blocks being
interposed.
As the whole surface of the ship is covered with the over-lapping plates, the
whole surface when moving is encased as it were with a layer of air on account
of the air passing out of the pockets such outflow of air being caused by the
movement of the ship through the water. The greater the speed of the ship the
greater the air layer. The air layer thus reduces the amount of the frictional
surface and the speed is increased. The action is automatic. In order to further
increase the speed steam can be introduced into the air chamber, so that both air
and steam can pass into and out of the pockets.
Dated this 5th dow of Ini 1900
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C., London.
Method and Construction for Reducing Friction Between the Surfaces
of Ships and the Water.
I, EDUARD LINDEMANN, of Schellingstrasse 41/1, Munich, in the Empire of
Germany, Engineer, do hereby declare the nature of my invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:.
-
By the movement of ships through the water an essential resistance is caused
by the friction, which hinders the fast movement of the same. By the friction
of the water on the surface of the ship a loss of power occurs and therefore a
diminution of speed. The greater the speed, the greater will be the loss of power
caused by the frictional resistance. By diminution of the frictional. coefficient
between the surface of ship and the water the resistance and therefore the loss of
power will be smaller.
Let. Q=The water pressure on the surface of ship.
f=The frictional coefficient.
1
Qf The frictional resistance.
v=The speed of the ship.
P=Qf The loss of power caused by friction.
The less the frictional coefficient, the smaller will be the loss of power, caused
by friction; the speed will therefore increase owing to the smaller loss of power.
The present construction has for object to produce by the movement of the ship
an air layer on the whole submerged surface of the ship, in such a manner that
the resistance by friction will be less and the loss of power smaller.
For this purpose the whole surface of the ship is provided with scale shaped
overlapping plates of such a kind, that they form pockets following one upon
another, constituting an uninterrupted series of aspirating organs, like the scales
of the fish, so that by the movement of the ship, air is sucked out of the slits
between the scale shaped overlapping plates. The effect of suction of the air by
flowing water results in consequence of the curved plates, the curve of which forms
a parabola and is directed contrary to the movement of the ship, so that the rush-
ing out of air by suction, results without resistance. In the annexed drawings,

page_text: Fig. 2 is a side view of the same.
Fig. 3 is a longitudinal section on the line a b.
Fig. 4 is a longitudinal section on the line c d.
Fig. 5 and Fig. 6 show the construction of the plates above and below the water
line respectively on a larger scale.
On the exterior of the ship narrow vertical overlapping plates a, b, c, d (Fig. 3,
Fig. 4, Fig. 5) are arranged which extend from the bulwarks to the keel of the
vessel (Fig. 1 and 2).
Each plate overlaps its neighbor in a similar manner to the scales of a fish
(Fig. 5). Between each of these plates a pocket (Fig. 5, Fig. 6) is formed, of
which the part m n (Fig. 1, Fig. 2) is closed at the mouth (Fig. 5) and of which
the lower part 1 (Fig. 1, Fig. 2) coming underneath the water line is open
(Fig. 6).
At the keel line 2 (Fig. 2) the pockets are closed. The parabolic curved
plates form pockets and are arranged so that between each of them a narrow
opening or slits under the water line is formed (Fig. 1, Fig. 2, Fig. 6). The
lower part n (Fig. 1) of these pockets conforms to the outline of the ship and
fits closely thereto, but the upper part mn is separated from the same, so that an
air chamber (Fig. 1 and 3) is formed. This air chamberk (Fig. 3) is open at
the bow of the ship and closed at the stern, so that by the forward movement of
the ship, air is forced into the air chamber and passes into all the pockets. The
air chamber (Fig. 1) is connected at its lower part to the pockets, so that the
air by reason of the pressure will pass into the pockets rushing out of the same
through their narrow openings s. The plates at the openings or slits of the
pockets are connected together at suitable points t r q x y z vw (Fig. 1). When
the ship is still the pockets below the water fill with water, on the forward move-
ment, the water not being a part of the ship flows from the slits of the pockets.
In consequence of the parabolic curvature of the overlapping plates (Fig. 5, Fig. 6)
the flowing of the water out of the pockets, and the drawing out of the air by the
flowing water results without resistance. Each pocket produces a strip of air
of the length of the ship's draught and of the width of two following slits.
air strips form together an uniformly extended air layer, covering the whole
submerged surface of the ship.
All
The production of the air layer results from the movement of the ship, since
the air forced into the chamberk (Fig. 3), passes into the pockets by air pressure
and rushes out by suction of the flowing water. The whole submerged surface of
the ship is covered therefore by a uniform air layer by which the friction is
diminished and the loss of power will be smaller,
The speed therefore increases.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:
A construction for the hull of ships, vessels or boats for lessening the friction
between their surface and the water, consisting of curved plates, preferably para-
bolic, overlapping each other, covering the ship's surface and forming an un-
interrupted series of pockets closed above the water line and open below the same
forming a slit between every two plates, for the purpose to produce by the move-
ment of the ship, an uniform air layer over the submerged surface, substantially
as described.
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C., London.