US1875629A

US1875629A - Propulsion of ships

Info

Publication number: US1875629A
Application number: US499585A
Authority: US
Inventors: Marconnet Georges
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-12-06
Filing date: 1930-12-02
Publication date: 1932-09-06
Anticipated expiration: 1949-09-06

Description

Spt. 6, 1932. G MARCQNNET 1,875,629

PROPULSION OF SHIPS Filed Dec. 2, 1930 Patented Sept. 6, 1932 i 1:11;;

UNITED STATES enonens MARCONNET, or rears, rnANoE;

rnorurisron or snrrs Application filed December 2, 1930, Serial No. 499,585, and in France December 6, 1929.

The present invention relates to the propulsion of ships, and aims at reducing the resistance oflered to their progress by the friction of the hull in the water.

To this eflect, the invention consists of blowing a great number of air bubbles into the water along the sides of the hull, more particularly at the frontof the ship. These air bubbles are meant to form a kind of emul- 10 sion with the water which has a lower friction coefficient than water.

In order to put this procedure into practice, one can, for example, build the front part of the ship on a length of several yards and as far as it is under water, with a double hull. The space between the two walls is supplied with compressed air under suitable pressure, and the outer wall is perforated by a great number of small holes which give escape to air bubbles without interruptlon while the ship moves. 7

Since the latter advances, while the bubbles rise to the surface, the bubbles will slide along the oblique outlines of the hulls surface, and thus they will form a coat of emulsion starting at the bows, which will cover a great part of the surface of the hull.

If necessary, other perforated walls can be arranged on the sides of the shi for instance near the middle of its lengt so as to extend as much as possible the advantage of the reduced friction in the water.

Calculations show that a slight reduction of the coefiicient of friction is sufficient to obtain a marked reduction in the fuel consumption, the speed remaining the same, or to in.- crease the speed of the ship with the same consumption of fuel; this, taking into conby a second wall 2 which forms together with the outer shell a narrow chamber which is connected by a system of pipes to a blower. (not shown) which is fed by any kindof compressor. The outer wall is perforated by a great number of little holes 3 spread over I the whole immersed surface of the hull, and over a length, which can be, for example, equal to one tenth of the length of the vessel, there being, for instance 250 holes per square meter. 1 These holes can have a diameter of 4 millimeters in the upper parts, and 6 millimeters in the lower parts. When the ship moves, air will be com- 1 pressed in the chamber 1/2 at a pressure slightly in excess of the water pressure at the level of the keel, so much so that a great a 1 number of bubbles will escape from all the '65 perforations in the ships side. Y These bubbles will rise along the hull and form against its walls an emulsion layer which will extend aft to a greater or lesser extent according to the speed of the ship, for 7 a instance covering the trapezoidal surface a b c d. If one wishes to covera greater .sur-- face of the sides of the ship, the chamber 1/2 can be extended backwards, especially in its lower parts, or one can arrange perforations along the keel, for instance, in order to inject compressed air at all suitable spots.

If necessary, one can also subdivide the chamber 1/2 by longitudinal partitions, and supply the superposed. compartments thus formed with air at a pressure corresponding to the depth of each below the water line.

In applying the present procedure to a ship already built, the actual hull would be used for theinner wall of the air chamber, .85 and one would fix onto the outside of the hull a perforated wall kept at a slight distance from the former by suitable means.

The invention is, of course, not limited to this practical form, and the means of inject ing compressed air into the water along the hull can be arranged in another form, perforatedtubes, flat nozzles, etc. a

One could also use in the place of air such gaseous fluids as may be available on board.

I claim:

In a ship, means for reducing the resistance offered to its advance by the friction of the water comprising double walls disposed at: the front part of the ship so as to form a chamber for the reception of compressed gaseous fluid, means for introducing such fluid into said chamber, and a plurality of apertures formed in theouter Wall of said chamher for permitting the escape of the compressed fluid, the cross-sectional area of which apertures increases with their depth of ime mersion in the Water as and for the purpose described; i In testimony whereof I have signed my name to this specification. p 7 r H GEORGES MARGONNET.