US2969035A - Ship stabilizers - Google Patents

Description

Jan, 24, 1961 J. v. Fou. 2,969,035

SHIP sTABILIzERs Filed June 19. 1959 2 sheets-sheet 1 @1.24, 1961 H. POLL 2,969,035

SHIP STABILIZERS Filed June 19, 1959 2 Sheets-Shet 2 2,969,035 sim sr'Annii'zEns .lohn Victor Fell, Beckenham, England, assigner to Muirhead d: Co. Limited, Beckenham, Kent, England Filed rune 19, 1959, ser. No. 821,521 Claims priority, application 'Great Britain May 20, 1959 '3 Claims. (Cl. 114-126) This invention relates to devices for stabilizing' or damping the roling motion of ships' and in particular to small ships and yachts by means of fins projecting laterally, from each side o-f the ship below the' water line. Such fins are normally of hydrofoil section and their planes are parallel to the now of water past the ship when in forward motionL so that they do not react with the water, that is to say, they'present zero angle of incidence to the water now. However, in order that the tins may act to stabilize the ship the angle' of incidence of the fins may be adjusted positively and negatively, i.e. they may be tilted in such a manner that the ensuing force due to the reaction between the fin and the water continuously opposes the sea forces causing the ship to roll. In this way the rolling motion is limited to a very small degree.

A power means to actuate' the nns is provided which may be hydraulic, electric or steam operated or combinations of the same. A well' known system uses `hydraulic rams supplied by available delivery pump. The power means and hence'the iin angle is controlled by a sensing means which measures one or more of the' functions of the roll, c g. displacement, velocity or acceleration and provide a control' signal proportional to a' single function or a combination of said functions.

Such power means and sensing means are well known and do not form apart of the present invention.

The invention relates to' an' ar'rangemeritV in which a plurality of fins are provided` dde'ach side of the' ship, suitably placed and of su'cl'l dimensio'nsrtliat' 'they'no 'not materially interfere with normal operation' and vmano'e'vring. Thus, they are placed at the cirvd'sec'tion between the Vertical `sides and sensibly' horizontal bottoni, and do not extend beyond the projection of these surfaces.

in other such arrangements such fins' are erected on and held to the side of the ship by` longitudinal'nieinbers and \\Abrackets or similar stiffening arrangements to withthrough the water. v

The invention relates'tol a part ul'ar nn construction one object of which is the avoidance' of hydrodynamic inefliciency due to the use of extraneous supports'. The omission of said extraneous supports also avoids a serious ineiciency in respect of the lift of the liris which would occur due to the upwardly'and downwardly moving Water (after de'lle'xionV by tli'e'nns) striking such supports and causing an opposing liftwhich'would'subtfact from the total lift available from the whole nn assembly.

The-invention consists of a ship lstabilizer n arrangement comprising a plurality of tins' provided along the side of the ship each iin being s'lippor' 'd for rotation about a stub-axle the ns havingcranliseecure'd thereto, in which the crank'sare linked by a connecting rod for simultaneous operation.

Each nn is supported on the equivalent o'f ay stub 'axle or pintle providing either asinglelongbearing or two bearings co-'operating with bearing' surfaces internal to the lin, such bearing surfaces beingtide from a' suitable stand the forces generated by the nn's dueto their passage g'rade' of hard rubber, resin impregnated fabric or other substance which provides a suitablev bearing surfaee'with water acting as the lubricant, allowances being made in the ntting of the bearings for swelling which may take place under conditions of continuous immersion in water. A suitable resin impregnated fabric ris available, under the trade name Tufnol.

In the construction the pintle and tinv are both in the form of castings and the pintle is provided with a groove or flange which engages with a split ring of TufnoL for example, for the purpose of retaining the tin or the pintle. Access to the bolts for securing the split ring may be obtainedV through holes suitably placed in the base of the pintle. The section through'the nn may Vary from the inner to the outer portions, the inner portion beingy the deeper section in order to accommodate a larger bearing where' the bending moment of the-pintle is greater and hence, la larger diameter of pintle is required.

Since the connecting rods must operate alternately under compression and tension,r they are ypreferably made of large diameter. The rods are preferably formed of sections and ends of adjacent rod sections may beconnectedby a flexible joint nthe'form of a split moulding of tough rubber, the moulding engaging with the spherical end of a crank pin attached to the extremity of the fin crank. The flexibility of lthis joint enables the system of connecting rods to respond to flexures in the ship structure andv further, to operate a system of ns mounted on a curved surface of the ship, each connecting rod being straight in itself.

The fins are preferably spaced suniciently far apart from each other so that interference of one tin on a succeeding nn or nns is reduced. StiIl further to diminish this effect the ns subsequent to the first may be dellected through a larger angle'. By way ofexample, the second, third and fourth nns might operate through angles progressively greater than the rst, with subsequent nns all operating at the same angle.

The movement of the lins'is controlled by a controlling means and a power means as hereinbefore referred to, the mechanical motion froml -the power means being passed via a shaft through the hull to a crank on one of the connecting rodsdisposed among-the group of ns. On larger ships there may be two or' more controls per side but on small ships oneAv control' n'nit could' operate all the req'uired tins'.

The nn's may be' subjeot to'l damage fromfloatin'g'objects, or -in the caseV of s"tfrandi-'r1g',-the ship may heel over and rest on theV iins; To yavoid structural damage to the ship it isa feature of the invention to make the` pintle definitelyl weaker' than its attachment to the sidedf the ship so thatin the' event vvof' overs'tr'ining, tlieiins` will break off beforedarnge is Cn's'ed to the hull. Asi an example, wherethe normal s'tressonthe pintle is 2 tons per in.2, they breaking ystressA may be made'- l5 tons per in?.

It is desirable that'thens" and all operating parts' which are exposed to the water aremadeof non-corrosive material such Ias Monel 4metal' althoughv stainless steel may alternatively be used for all o'r sorn'e portions, for example, the connecting rods anclpintles. Alternatively, a fabricated construction by' `vv'eldin'g may be used instead of castings. The-surfacesy whichare' notoperating' or bearing surfaces may alternatively be'of other materials covered witha protective'coating suehas'- rubber or plastic having botliprotectivef andantiifoling properties.

The invention will now be further described with reference to the drawings in which:

Figure-l is apart section through a'n,

Figure .is a plan'of ann,

Figure 3 is' an elevation of afin,

Figure 4 shows a group of ns attached to a ships side,

Figure 5 is an alternative arrangement of fins,

Figure 6 is an elevation of a iin in accordance with the arrangement of Figure 5,

Figure 7 is a section olf part of a ships hull showing a fin assembly in laccordance with the arrangement of Figure 5,

Figure 8 is a flexible coupling,

Figure 9 is an alternative exible coupling,

Figure l is a detail of a crank.

Figure l shows pintle mounting plate 1 bolted to ships side 2 and supporting pintle 3 disposed within n 4. Pintle 3 is tapered and provided with a bearing surface 5 at its extremity and a further bearing surface 6 of larger diameter at the inboard end. Fin 4 is rotatively supported on pintle 3 by bearings 7 and S engaging with bearing surfaces and 6 respectively.

Shoulder 9 adjacent large bearing surface 6 together with the reduced diameter lil of pintle form a groove or slot containing split ring 11 which is further enclosed by an annular recess 12 in the inboard end of n. Bolts 13 suitably disposed round the outer edge of split ring 11 secure the latter to fin. Thus, the fin is secured to the pintle by the split ring but is free to rotate about said pintle on bearings 7 and 8. Fin 4 and pintle 3 may be of cast construction in a non-corrosive material such as Monel metal or stainless steel. Bearings 7 and S and split ring 11 are of hard rubber or resin impregnated fabric, and bearing clearances a, b, c or d are water lubricated and adjusted to allow for swelling of the bearing material due to water immersion. Hole 14 drilled concentrically in the i-nboard end of pintle 3 is provided to reduce the strength of said pintle to a degree that will allow the pintle and n to break olf in an emergency without damage to the ship structure. Holes 15 drilled Ithrough the pintle mounting plate 1 give access to bolts 13 when securing the n to its pintle. Angular motion is imparted to the lin over crank 16 terminating in crank pin 17. The crank may be formed integrally with the iin or welded or otherwise attached thereto. The end of crank pin is in the form of a sphere or knuckle l which engages with spherically formed exible joint 19 in the assembly of connecting rods and indicated in the gure by the broken line surrounding the knuckle.

Figure 2 is a plan and Figure 3 is a-n elevation of the n assembly wherein like reference characters refer to like parts in Figure l.

Figure 4 shows an assembly of fins 4 arranged along the curvature of a ships side 2 and actuated by connecting rods 20. Flexible joints or couplings 19 linking adjacent connecting rods enable said connecting rods to take up positions tangentially to the curvature of the hull without imparting undue strain. Longitudinal motion for actuating the fins is imparted to said connecting rods by shaft 22 passing through watertight gland 23 to the outside of the ship and terminating in a crank. This structure is shown in greater detail in Figure 10 in which shaft 22, operated at its inner end by the power means (not shown) passes to the outside of the ship through watertight gland 23. The outer end of shaft 22 terminates in crank 24 having a forked end. This forked end engages two abutments 25 on connecting rod 20 whereby rotary or oscillatory motion of the crank is translated into linear motion of the connecting rod.

The assembly of connecting rods around the side of the ship will cause a degree of turbulence and drag in their passage through the water tending to slow up the ship and to obviate this undesirable tendency the connecting rods may be contained in a channel within the ship. The crank pins of the various tins -associated with the assembly pass through curved slots in the ships side where they connect with their respective exible joints in the system of connecting rods in a similar manner to the construction of Figure 4. An advantage of this construction is that the channel containing the connecting rod assembly is in eifect an additional bilge stringer of a form contributing greatly to the strengthening of the ship. Details of the construction are shown in Figures 5, 6 and 7, in which like reference characters refer to like parts throughout the several views. Referring rstly to Figure 7 which is a traverse section of a part of the hull (on line A-A, Figure 5) in the region of the b-ilge, fin 4 is attached to the hull as shown and is so proportioned that its extremity does not protrude beyond the projections of the ships side and bottom as indicated by the broken lines. Crank pin 17 of fin 4 protrudes into the channel 26 with-in the hull through curved slot 27 where it connects with llexible coupling 19 uniting connecting rods 20 and 20a (Figure 5). Channel 26 may be of welded construction in steel and welded to the sides of the ship for watertightness and strength. The channel is widened at a suitable point X (Figure 5) to accommodate the watertight gland of Figure l0 associated with the n actuating shaft 22.

Figure 6 shows a part elevation of the ships hull in the region of tin 4. In the figure, the broken lines represent the channel within the hull. Slot 27 cnt in the ships side enables crank pin 17 to pass into channel 26 and connect with a flexible coupling (not shown) in the System of connecting rods located longitudinally within said channel.

Figure 8 shows a method of uniting two connecting rods by means of a flexible coupling to impart a degree of resilience between the rods so connected. The flexible coupling 19 consisting of two halves e and f is moulded in a suitable grade of hard rubber. The centre portion is preferably in the form of a hollow sphere, the internal diameter (indicated by the broken line) being a working tit with respect to the spherical end or knuckle 1S of crank pin 17 (Figure l). The spherical part is provided with two oppositely facing cylindrical extensions or stubs 28 which are a squeeze t in the ends of the tubular connecting rods 20 and 20a. ln assembly, the two halves of the flexible coupling are placed so that the central portion encloses the aforementioned knuckle on the crank pin. The cylindrical extensions are then forced into the ends of the connecting rods and secured by through bolts 29. In Figure 9 an alternative construction is shown in which slots 29 are moulded in the cylindrical extensions 28 and the ends of the hollow connecting rods 20 and 20a are turned inwardly to engage said slots as shown in the figure. The ends of the connecting rods are further provided with a number of longitudinal slots or saw-cuts (not shown) to enable the ends to be opened up or increased in diameter. To assemble the flexible coupling in this construction the ends of the connecting rods are opened out by forcing in a conical tool for example. This will allow the cylindrical extensions of the exible coupling to pass easily into th ends of the connecting rods and for the inwardly turned ends of same -to register with slots. Clamping rings 3i) are then placed round the ends of the connecting rods and tightened by means of screws 31 until the inwardly projecting ends of the rods are seated in slots 29.

I claim:

l. A ship stabilizer comprising a ships hull, a .plurality of stub axles mounted outside the hull, spaced water-lubricated bearings mounted on the stub axles, tins mounted on the bearings for rotation about the stub axles, cranks secured to the tins, a connecting rod secured to the cranks for simultaneous operation of the ns and formed of sections connected by moulded flexible joints which also engage the ends of the cranks, a watertight gland in the hull and operating means for the connecting rod extending through the gland.

2. A ship stabilizer as claimed in claim l, in which the stub axles are made only of such a strength that they will break ol in the event of over-straining before damage is caused to the hull.

Pr., .e

5 3. A ship stabilizer comprising a ships hull, a plu- References Cited inthe file of this patent raliy Of. Stub aXleS mOllIled Outside the 111111, the Stl'lb UNITED STATES PATENTS axles being made only of such strength that they w111 break off in the event of over-straining before damage gtucr ATulyl is caused to the hull, spaced water-lubricated bearings 5 u pr' d th b l n td h b 2,550,752 Allan May 1, 1951 munte On e Stu ax es, s mo'un e ont e eamngs Mar. 24

for rotation about the stub axles, actuating means mounted to form part of each fin and means extending FOREIGN PATENTS through the hull to operate the actuating means. 10 496,524 Great Britain Dec. l, 1938

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