US1818705A - Method of and means for propelling ships - Google Patents

Description

Aug. 11, 1931. F. w. GAY

METHOD OF AND MEANS FOR PROPELLING SHIPS Filed April 15,- 1928 ATTORNEYS Patented Aug. 11, 1931,

v UNITED STATES P ENT- OFFICE FRAZER w. GAY, or NEWARK, new JERSEY METHOD OF Am) MEANS l Application filetl April 13,

h It is well known ,that'ships ordinarily are propelled by paddle Wheels or by screw propellers. The screw propeller method is the most common and is attended with many disadvantages of which the following are the most important; The over-all efficiency expressed in ratio of tow-rope power to indicated engine room power, is seldom great: v er than fifty per cent. The driving mechanism, if direct, is large and heavy. If high speed turbines are used as a source of power, mechanical and electrical speed reducing means are required in transmitting this power to the necessarily relatively slowrevolving propellers. i I

Furthermore, it is known that ships like any other object forced through Water, moving at high speeds produce waves which in crease the pressure orresistance on'the bow of the ship and impede movement thereof. Such waves travel at the speed of-the ship, and at distances from crest to crestwh-ich increase rapidly with the speed fromapproximately eighty feet at twelve knots to five hundred feet at thirty knots.

Calculations show that a pressure equal to six inches of water head at the stern of a cargo boat in excess of' the pressure at the bow'issufficient 'to drive such boatat its usual speed of ten totwelve knot sper hour,

while in the case of lar e high speed passenger ships, like the aum'tomz'a, 'a differ- 'ence inpressure equal to a head of three feet "of water or even'more would be required; One object of my invention is to provide a noveland improved method ofship propul sion consisting in creating such a difference between the pressures of the water at the bow and the stern of a ship and'utilizing said 40 pressure difference for propelling the-ship thereby eliminating the. above-mentioned disadvantages of screw-propeller propulsion;

1 Another object is to provide a method of propelling ships which consists in producing a pressure wave at a point in advance of the bow of the ship sov that the ship may 7 take entrance in the trough following such pressure wave. It'is evident at once, that if the ship takes its. entire entrance in; the

FOR PROPELLING srrrrs 1928. Serial No. 269,688.

anotherwave which will counteract on the,

previous pressure. wave. It is necessary, therefore, to produce a pressure Wave of sufficient magnitude that after a part of its trough has beenneutralized by the wave of entrance of the ship, there remains enough trough to balance the skin friction of the ship and stern cavitation.

Another object is to provide novel and improved means for reducing thehydrostatic pressure at the bow of a ship.

ther objects are to provide novel and im- I proved means for producing such pressure waves in advance of the ships bow; to provide such means whereby the distance ahead of the bow at which such pressure waves are produced may be varied; to provide a method of ship propulsion consisting in imparting energy to the water at a point in advance of the stern or exit portions of a ships hull to increase the hydrostatic pressure or head at the stern; to provide means for so imparting energyto the water ahead of the exit portions ,7 of'a ships hull, and to obtain other advan-' tages and results as will be brought out by the following description.

' In the accompanying drawings I have schematically illustrated my method of and means for propelling ships, but it should be understood that this is primarily for'explain- 'ing the principles of the invention and that many modifications thereof may be made by those skilled in theart without departing from the spirit or scope .of the invention.

Referring to said drawings in which corresponding and like parts are designated throughout the several views by the same reference characters, 9 Figure 1 is a schematic plan view of a ships hull showing the principles of one form of my method and means; V

FigureQ is a longitudinal sectional view taken on the line of Figure 1; i a 5 Figure 3 is a plan view of a modified form of the invention; and a I Figure 4 is a similar view of a further modification. Specificallydescribing'the form of the invention shown in Figures 1 and 2, the reference character 1 designates the hull of a ship having sides of entrance 2, 2 and a projection 3, a pipe in the form shown extending forwardly from the bow below the normal water level 4, and formed with a downwardly directed opening 5. This pipe is connected at 6 to any suitable source of compressedair. In operation initially slow motion is imparted to the hull in any suitable manner by a screw propeller, and compressed air is eject-ed in a continuous stream from the opening 5. This creates a pressure waves 7, 7 at each side of the hull and at a point ahead of the bow and following troughs 8, 8 which extends throughout the length of the entrance sides 2, 2. The ship therefore takes its entrance in said trough the surface of the water in which is so low that only slight impedance by the water to forward movement of the ship is produced. The resistance by the water .to movement of the ship is thus materially less than it would be according to known practice. This pressure wave gradually flattens out or decreases in height shown by dotted lines 921-1111 10, and as the ship travels forwardly is influenced forwardly by the pressure of the wave on the stern 11 as indicated at 12.

The invention may be utilized as an auxiliary to ()I'dlILdI'y screw propeller n'opulsion, the reduction in hydrostatic pressure at the bow caused by the air emitted from opening 5 decreasing the resistance by the water to the force exerted by the propeller; but the air may be ejected from the opening 5 in such volume and at such ruessure that the pressure Wave when the stern reaches it as at 12, has

sufiicient head in excess of the pressure at the bow to exert a propelling force on the ship.

In Figure 2, Thave shown further means to increase the energy in the wave ust before the stern reaches it, said means comprising an opening 13 in the shlps hull connected to the an supply pipe 6. By this means the height .or pressure head of the wave at point 14 is increased and the pressure thereof imparted to the stern at 12. If this increase in pressure head is only slight, it will serve only to reduce the retarding effects on the hull of stern cavitaltion, but the pressure may be so great as to exert 'a propelling force on the stern and drive the ship. The distance between the openings 5 and 13 must be so correlated to the length and the speed of travel of the ship, that the air pressure will be applied at the proper point 14.

It may be desirable to provide means for varying the distance ahead of the entrance surfaces 2, 2 at which the pressure wave 7 is produced so that the pressure wave is located in advance of the hull of the ship, a distance proportional to the square of the speed of travel of the hull which will vary at different times, and for this purpose I may make the pipe 3 slidably adjustable through the bow, or the projection may be made in tegral with the hull and the opening 5 formed at different distances from the entrance surfaces 2, 2, as shown in Figure 8, or a plu rality of openings any one of which may be used, can be provided.

It is also possible to provide for the hull. taking entrance in a plurality of stages, as shown in Figure 41-, where two projections 15 and 16 of different widths connected by entrance surfaces 17, 17 are provided. The projections 15 and 16 have respective openings 18 and 19 to eject compressed air. The pressure wave 20, produced by the air from opening 19 is partially neutralized by the first stage of entrance taking by the surfaces 17, 17, and the pressure of said wave is then increased by the air from opening 18 to form a trough in which the second stage of entrance is taken by the surfaces 2, 2.

I do not desire to be understood as limiting myself to the precise form of taking entrance illustrated, as it is possible. to make the bow of the hull shallow and take entrance in the direction of draft only in the:

wave troughs.

By moving the openings 5, 13, 18 and 19 forwardly-or astern, I may compensate for the changes in wave length i. e., distance be tween the crests of the wave, which varies after it has once been started by other means] I do not wish to be limited to the use of compressed air for creating the above-mentioned pressure waves. I may for instance discharge a mixture of air and gas or air and oil vapor in the form of, a succession of huge.

bubbles and explode these bubbles immediately after their emission, thereby creating a series of closely spaced points or zones of pressure. Such a succession of zones of pressure willgive substantially the same effeet as the jet of air.

Having thus described my invention, what I claim is:

1. A ships hull having a forward projection from its bow submerged in the water, and means carried by said projection to produce a pressure wave in advance of the bow, and means for adjusting the last-named means to vary the distance between the crest of said wave and the bow of the hull.

2. A ships hull having a forward projection from its bow submerged in the water and exit surfaces, means carried by said projection to produce a pressure wave in advance of the bow, means for imparting energy to the water ahead of said exit portions to increase the hydrostatic pressure on said exit portions, and means for adjusting said means relative to each other and the sh1p in accordance with the speed of travel of the ship.

3. A ships hull having entrance surfaces, and means for producing a, pressure wave at a point ahead of said entrance surfaces of said hull a distance proportional to the square of the speed of said hull so that said entrance surfaces take entrance in the trough following said pressure wave.

4. The method of propelling ships consisting in establishing a pressure wave at a point ahead of the hull and adjusting thedistance of said Wave in advance of the hull in proportion to the square of the speed of travel of the hull. v

FRAZER W. GAY.

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