US2223562A

US2223562A - Antirolling device for ships

Info

Publication number: US2223562A
Application number: US255843A
Authority: US
Inventors: James V Giliberty
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-02-11
Filing date: 1939-02-11
Publication date: 1940-12-03
Anticipated expiration: 1957-12-03

Description

Dec. 3, 1940.

J. V. GILIBERTY ANTIROLLING DEVICE FOR SHIPS Filed Feb. 11, 1939 3 Sheets-Sheet l INVENTOR James V. Gili bari- Y ads (10% 2;

ATTORNEY Dec. 3, 1940. J. v. GILIBERTY ANTIROLLING DEVICE FOR SHIPS Filed Feb. 11, 1939 3 Sheets-Sheet 2 INVENTOR JamesV. Giliberi ATTORNEY Dec. 3, 1940- J. v. GILIBERTY ANTIROLLING DEVICE FOR SHIPS Filed Feb. 11, 1939 3 Sheets-Sheet 3 INVENTOR JAMESVGILIBERTY BY 3 ATTORNEY Patented Dec. 3, 1940 UNITED STATES PATENT OFFICE 2,223,562 ANTIROLLING DEVICE FOR SHIPS James V. Giliberty, Hempstead, N. Y. Application February 11, 1939, Serial No. 255,843

-2 Claims.

I'his invention relates to antirolling devices for ships of the type in which stabilizing fins projecting laterally from the side of the ship are turned about an axis perpendicular to the longitudinal axis of the ship in such a direction as to oppose the rolling movements of the ship.

When such fins are located a substantial distance either forward or aft of the ships center of gravity, they oppose the pitching movements of the ship as well as its rolling movements.

It has been proposed to change the angular positions of such fins by hydraulic or mechanical means located inside the ship and controlled by i a gyroscope. While such means are Very efiicient,

' pitching movements of they are expensive to construct. They are also quite complicated and are therefore more susceptible to mechanical derangement.

The principal object of the present invention, therefore, is the provision of simple, inexpensive means for automatically changing the angle of attack of such fins in such a direction that the flow of water past the fins due to the ships longitudinal movement through the water exerts pressure on the fins to oppose the rolling-and/or the ship.

Where gyroscopic control is used the angular movement of the ship relatively to a horizontal plane is employed to change the position of the stabilizing fins. According'to the present invention the angular movement of the ship relatively to the water is employed for that purpose, thereby greatly simplifying the construction and operation of the stabilizer.

Broadly speaking, the invention involves controlling the angular position of the fin by means of a plate, which will hereafter be called the control plate, mounted on the outside of the ship in such a way that it can move upwardly relatively to the adjacent part of the ship as such part moves downwardly through the water as the result of the upward pressureof the water on such plate.

On a large ship the lateral angular movement of its sides through the water due to rolling may be a considerable number of feet. The movement of the control plate relatively to the ships side, may not be in excess of a few inches. As a result the total movement of the plate is downward, although there is a simultaneous movement ofv the plate upwardly with respect to the adjacent part of the ships side. It follows, therefore, when reference is made to such plate moving upwardly, that it would be more accurate to say that it does not move downwardly as rapidly or asfar as it would had it been rigidly secured to the ships side. However, for convenience, movements of such plate and the other parts of the stabilizer will hereafter be referred to as upward or downward when such parts move up 5 ward or downward with respect to the adjacent side of the ship.

The control plate mentioned above is used to control the direction in which the fins are inclined with respect to the horizontal and also the magnitude of their angle of attack. It may control the angular position of the fins by controlling the application of motive power from the ships power plant to the stabilizing fins. A simpler method is to connect each plate to an adjacent fin in such a way that the force exerted against the plate, resulting from the rolling and/ or pitching of the ship, is transferred to the stabilizing fin in such a day that the angle of attack of the latter is changed in sucha direction that the pressure of the water on the fin opposes the rolling and/ or pitching movement of the ship. In either case, the rolling and/or pitching movement of the ship acting through the control plate controls the angle of attack of the fin both as to direction and also as to magnitude with respect to the fore and aft flow of water.

Where the stabilizing fin is turned as'the result of a direct connection between the stabilizing fin and the control plate, the stabilizer units are self-contained and positive in action. This results in greatly simplifying the construction and operation of the stabilizer and thereby contributes to greater reliability.

Another simple, and the preferred, method is to use the control plate to throw into operation fin deflecting means which derive their deflecting force from the forward motion of the ship. It is advantageous to use the pressure created by the forward movement of the ship through the water to turn the stabilizing fin for the reason that, per unit of area, it is so much greater than the pressure due to rolling movement. For example, one large ship has a maximum circumferential rolling movement of around 1.8 feet per second. On the other hand, the same ship at full speed travels at 30 knots or more, which is equivalent to a speed of over 50 feet per second.

With either of the last two mentioned arrangements, the angle of attack of the stabilizing fins is controlled by the controlplates independent of anyv motive power for said control; other than the forces resulting from the ships angular movement and. the ships forward velocity.

j thefin to produce allel to, or coincident with, that of the stabiliz-- ing fin, or second, about an axis at right angles stabilizing finand to the longitudinal axis Ofthe to the axis of rotation of the usually parallel ship.

In all cases, the normal or neutral "position of the control plate is such that its plane isparallel to the direction of fore or aft movementof the ship. Ifthe control plate is mounted so as ,to turn about an axis which. is also parallel to such direction of movement, its plane is always parallel to the fore and aft water fiow. ,If, on the other hand, the control plate is arranged to turn about an axis parallel to, or coincident with, that of the stabilizing fin, its plane does not maintain this parallelism. The extent. to which parallelism is departed from for any given lateral movement of the-center of pressure of the, control, plate depends on how far suchcenter of pressure is from the axis about which such plate swings.

Any angular velocity of roll produces a strong reaction on thecontrol plate. This reaction is utilized to actuate the stabilizing fin, through gears, links, levers, or through the medium of a pilot rudder attached to the stabilizing, fin. The connection provided between ,the stabilizingfin and the control plate is such that movement, of ,thecontrol plate causes the leading edge of the .stabilizingfin to move in the same direction as the control plate, thereby producing a force on the hull tending to checktherolling motion of the ship.

As the stabilizing fin moves edgewise through the water as. theresult of the forward movement of the ship,

,of the-'shipdepends on how well the fin is balanced. The nearer the turning axis is to the balance pointthe less the force required.

If the fin were perfectly balanced hydrodynamically, the force required to turn it would be only that required to overcome the friction of the support. In practice, perfect balance is impossible as the position of the turning axis of perfect balance varies with the speed of the ship; the higher the speed the nearer such axis would have tobe to the leading edge of thefin. The important point is that two forces have to be overcome to cause the leading both reduced by mounting the fin on edge of the fin to incline upwardly as the fin 'duetofthe rolling motion of the ship and that due to the "turning movement required to give thefin a correct angle of attack. Both these forces are in the same direction and they are the balanced rudder principle. To prevent the fore and [aft flow of water turning the fin broadside on or completely Jaround through 180, the fin should be mounted with its axis of rotation forward of thebalance point of the fin at the maximum speed of-the ship.

the force required to turn the fin out of parallelism with the direction of movement the force On the other hand, it is desirable that the control plate should be not only wholly unbalanced but also mounted so that, as it moves upwardly as the adjacent side of the ship moves downwardly, it does not move markedly out of parallelism with the fore and aft flow of water. Any marked angular movement of the control plate away from parallelism with the fore .and aft flow means an unnecessary checking of the forward movement of the ship and ,usually also exerting a thrust laterally inopposition to that produced by the stabilizing fin when turned so as to oppose the rolling motion of the ship. A close "approach to constant parallelism is obtained by mounting the, control plate on the end of a long .arm so that over a considerable range of vertical or lateral movements there is only a slight change in the angle of attack with respect to the fore and aft flow of water, or by mounting the control plate so that its axis of rotation is ap' proximately parallel to the longitudinal axis of theship. v

A fin freely rotatably mounted on a shaft proaxis of rotation forward of the balance point of the fin would be deflected by the rolling action of the ship in such a direction that such fin would accentuate the rolling, i. e. give it an angle of attack in the wrong direction. In order to prevent this, it becomes necessary by auxiliary means to a'pply'forces which not only overcome the above. mentioned inherenttendency to produce the wrongangle of attack, but also to produce a deflection of the fin in the tion, so that the desired angle of attack in the right direction to resist roll is. produced.

Various embodiments of myinvention are illustrated, by Way of example, in the accompanying drawings, wherein:

Fig. 1 is a plan view'of my stabilizer Fig. 2 is asection on the line 2-2 of Fig. 1;

Fig. 3-is a diagrammatic sectional view of the stabilizer of Fig. 1, showing the position of the parts as the stabilizer is pushed upwardly through the water by the rolling of the ship;

Fig.4 is a view similar to Fig. 3 showing the position of the parts as the stabilizer is moved downwardly through the water by the return roll of theship;

Fig. 5 is a side'elevation of a ship equipped with my stabilizers in place of the usual bilge keels;

Fig. 6 is a front elevation Fig. 7 is a perspective view of the form of stabilizer shown in Fig. 1; and

Figs. 8 to 12, inclusive, are perspective views of modified forms of my stabilizer.

In the preferred form Figs. 1 to 7, inclusive, l5 represents the stabiliz-' ing fin, l 6 the control plate, and pivotally connected to both the stabilizing fin and control plate.

The stabilizer as a whole is rotatably mounted on a stub shaft 20 having a. flange 2| at one end the preferred form of of the same; I

jecting laterally outwards from the hull with its opposite direcof stabilizer shown in v I! a pilot rudder by which it may be secured to the side 22 of the 25 the mid-portion of which is attached to the front end of the fin by a screw 26, while the ends of the spring are coupled together by

tension adjusting screws

21 and 28. On the stub shaft 20 is mounted a cam 30 attached to a set-screw 3|. This cam has fiat sides against which the two halves of the spring press. As the fin turns either way from the position shown in .Fig. 2, the two halves of the spring are forced apart.

The construction shown has the advantage that the fin can be turned vso that it can operate as a stabilizer when the ship is going astern as well as when it is going forward.

Rotatably mounted on the shaft 20 between the flange 2| and the cam 30 is an arm 35, slotted at 35 (Fig. 7) at its rear end to slidably receive one edge of the control plate H5. The control plate I5 is coupled to the fin l5 by a pilot rudder H. The latter is pivotally connected to the fin I5 by

lugs

31, 38 and to the control plate l6 by a lug 39 and a pin 40.

When the ship rolls, the fin [5, control plate l5 and pilot rudder I! assume the positions shown in Figs. 3 and 4 alternately. When the ship rolls in the direction of the arrow A (Fig. 3) so as to push the stabilizer .as a whole upwards through the water, the control plate is pushed downwardly in the direction of the arrow B. As shown, this downward movement of the control plate has moved the rear edge of the pilot rudder downwardly into the path of movement of the water flowing longitudinally of the ship in the direction of the arrow C, due to its forward movement. The pressure on the pilot rudder so produced has restricted the downward movement of the control plate and at the same time pushed the rear part of the fin l5 upwardly. This last mentioned effect is the important one, as it is the one which results in the deflecting of the stabilizer fin in such a direction as to counteract the rolling movement of the ship. When the return roll takes place, the movements are all reversed, as indicated in Fig. 4.

It may be said that the control plate is floating, that is, it has complete freedom of movement in either direction from its central position. It follows then that a lateral movement of the fin unit which is equivalent to the movement of the ship in the direction of arrow A results in the movement of the control plate in the direction of arrow B. This relatively opposite movement is caused by the resistance offered by said plate to lateral movement through the water. Since the control plate is pivotally connected to the pilot rudder it follows that the movement of the control plate causes the pilot rudder to assume an angle of attack relative to the normal streamlines. Through the medium of the pivot connections 31 and 38 (Fig.1) the resultant force on the pilot rudder due to forward ship velocity then acts to give the stabilizing fin proper, its correct angle of attack. This last mentioned effect is the important one, as it is the one which results in the deflecting of the stabilizer fin in such a direction as I to counteract the rolling movement of the ship. It will be noted that the pilot rudder is balanced, i. e. the axis about which it turns is well aft of its leading edge. As a result it is readily turned by the control plate.

It will be noted that the magnitude of the angle of attack of the stabilizing fin proper is also automatically controlled. When a ship is in a calm sea there is no angular velocity and therefore the stabilizing fin, pilot rudder, and control plate assume their neutral or central movement.

position. A slight angular velocity resulting ment of the control plate with a corresponding slight movement of the pilot rudder and stabilizing fin. A large angular velocity resulting from a heavy seaway will cause a corresponding greater movement of the control plate, with a consequent greater movement of the pilot rudder and stabilizing fin. It follows then that the corrective moment is automatically controlled, and its magnitude is proportional to the angular velocity.

It will be further noted that the action of the fins is such that they produce a force in a direction opposite to that in which the stabilizing unit as a whole is oscillating. Therefore, the location of said fins on a ship may be such that they can produce forces to oppose rolling and or pitching.

In a mixed sea where intermittent rolling and pitching exists, the stabilizing fins herein described automatically adjust themselves to those conditions. The fins respond immediately to any roll or sequence such roll or pitch may be or regardless of what combination of roll or pitch may exist.

It is possible to do without a pilot rudder, and Figs. 10, 11 and 12 show three forms of construction in which it' is not used. Further, it is not essential that the control plate swing about an axis perpendicular to the ships side. The

control plate may be mounted so as to turn about a horizontal axis parallel to the ships side, as shown in Figs. 8, 9, 11 and 12. These modifications are illustrated to show in what diverse ways the general principles of my invention may be carried into practice.

In the form shown in Fig. 8, the stabilizer fin 50 is mounted to turn about a shaft (not shown) projecting outwardly from the ships side. Journaled on this shaft and rigidly secured to the fin 55 is a sleeve 51 carrying a bevel gear 52. The control plate 53 is rigidly mounted on a shaft 54, journaled in

bearings

55 and 55 secured to the ships side. Non-rotatably secured ,to the forward end of the shaft 54 is a bevel pinion 51 inmesh with the bevel gear 52. If the stabilizer is pushed downwardly through the water by the rolling of the ship, wardly, turning the shaft 54 and thereby turning the fin 59 so that the water flowing longitudinally along the ships side strikes the under side of the fin and produces an upward thrust on the stabilizer which counteracts the rolling On the return roll the control plate swings downwardly and presents the top surface of the fin to the longitudinal flow of water. By reason of the fact that the control plate is wholly unbalanced and the stabilizer fin is largely balanced, a comparatively small upward force on the control plate will produce a very much greater upward force on the fin 50, and vice versa.

If desired, the turning of the stabilizing fin 50 may be aided, as shown, by a pilot rudder 6U pivotally mounted at BI and 62 in a recess in the rear edge of the fin. This rudder has an arm 63, slotted at 64 for the reception of a pin 65 extending from the outer margin of the control plate 53. This pilot rudder 60, although somewhat smaller, acts in the same way as the pilot rudder I! in the form of construction shown in Figs. 1, 2 and 7.

The form of stabilizer shown in Fig. 9 is simithe control plate swings up;

from a moderate sea will cause a slight movepitch movement regardless of what lar to that of Fig. 8 except that the fin 70 is turned by the control plate 1| solely through the intermediary of the pilot rudder 12. In this case, therefore, the pilot rudder is a necessity, not merely an optional accessory, as in theform shown inFig. 6. The stub shaft 68 andspring 69 in this stabilizer is similar to the corresponding parts of Fig. 1.

Figs. 8, 9 and 10 show various forms of stabilizer in which no pilot rudder is used. In Fig. 10 the stabilizer fin is rotatablymounted on a shaft 16. The control plate 71 is rotatably mounted on a stub shaft 18, so that it swings about an axis parallel to. but spaced apart from that about which the fin 15 turns. To cause the rear part of the fin 15 to move downwardly while the control plate moves upwardly and vice versa, the control plate is provided with a forwardly extending arm 79, slotted at 80 for the reception of a pin 8| projecting from the inner edge of the fin I5.

In Fig. 11 the control plate 85 is hingedly connected to the ships side. The fin 86 has a forwardly extending arm 81 slotted at 88 to receive a pin 89 projecting from the outer edge of the plate 85.

The stabilizer of Fig. 12 comprises a fin 96 rotatably mounted on a shaft 91 and provided with leaf springs 94 which cooperates with a fiat sided cam 95 in exactly the same manner as the spring and cam of the form shown in Figs. 1, 2 and 7. The diiference in this case, however, being that said springs, cam and adjusting screws 93 are placed inside the hull, and secured thereto. Extending rearwardly from the inner part of the fin 96 is a shaft 98 on whicha control plate 99 is pivotally mounted. Leaf springs I09 attached to the fin and extending rearwardly, one each side of the controlplate, serve to yieldingly hold the latter in substantially the same plane as the fin, until rolling or pitching commences.

The forward edge of the plate 99 is enlarged at its outer end so as to provide a surface HH having area sufiicient to offer considerable resistance to the longitudinal flow of water along the ships side. In the beginning of a downward roll, the control plate 99 is deflected upwardly while fin 96 is yieldingly held neutral by means of the springs 94. Having moved upwardly, the force due to forward ship motion acting on the surface of NH, causes the trailing edge of fin 96 to move downwardly, thus causing it to be in the correct position to oppose the rolling movement.

In the preferred form of stabilizer shown in Fig. 1, the cam 39 and leaf spring 25 is shown outside the hull. It is to be understood that the arrangement of the cam and spring inside the hull as shown in Fig. 12, can also be applied to Figs. 1, 7 and 9. This arrangement has the advantage in that it enables the fin to be set to its neutral position at any point along the hull. Thus, if a fin is placed at a point where the streamlines are out of parallelism with the lonhind its trailing edge to produce gitudinal axis ,ofthe ship dueto eddy currents or to the Wave making eifect of the ships hull, adjustments of the fin to suit those conditions can easily be made. Having the cam and spring on the inside of the hull also has the advantage in that the spring tension can be adjusted While the ship is underway.

What is claimed is:'

1. An'antirolling device for water-borne ships comprising a stabilizing fin having leading and trailing edges pivotally attached to the side of the ship, the axis of said pivot being substantially perpendicular to the axis about which the ship rolls and also at a substantial angle to the vertical central plane of the ship, said .fin being mounted on its pivot so that said pivot is a substantial distance ahead of the geometrical center of said finand a substantial distance bea balanced rudder action, a control plate pivotally mounted on the side of the ship to turn about an axis fixed with respect to the ship, the axis of the pivot of saidplate being outside the body of but in'the same plane as said plate so that the latter is unbalanced, the last-mentioned axis also lying in the plane which includes the rolling axis of the ship and that part of the side of the ship to which the control plate is attached to permit the latter to be moved by the water with respect to the ship with rolling movements of the ship, and means interconnecting the control plate and fin for turning the stabilizingfin so constructedand arranged that the trailing edge of the fin moves about the axis of the fin in the same direction as that in which the adjacent side of the ship is moving as the result of such rolling movement.

2. .An antirolling device for water-borne ships comprising'a stabilizing fin having leading and trailing portions pivotally attached to the side of the ship, the axis of said'pivot being substantially perpendicular to the axis about which the ship rolls and also" at a substantial angle to the vertical central plane of the ship, said fin being mounted on itspivot so that said pivot is a substantial distance ahead of the geometrical center of said fin and a substantial distance behind its trailing edge to produce a balanced rudder action, a control plate located to the rear of said fin, said control plate having leading and trailing portions, a supporting arm connected to said plate and pivotally connected to the side of the ship at the same point as said fin but movable independently of the latter, a pilot rudder having leading and trailing portions, located between the leading portion of the control plate and the trailing portion of the fin and having its leading portion connected to the trailing portion of the fin and its trailing portion connected to the leading portion of the control plate whereby movement of the control plate resulting from lateral pressure of the water due to rolling moves both the pilot rudder and stabilizing fin.

- JAMES v. GILIBERTY.