This application claims priority to German patent application no. 10 2014 217 227.6 filed on Aug. 28, 2014, the contents of which are fully incorporated herein by reference.
The present disclosure is directed to a fin stabilizer for stabilizing a watercraft and to a watercraft including a fin stabilizer.
Stabilizers for watercraft, in particular fin stabilizers, may be used both for stabilizing watercraft while underway (while operating or traveling) as well as for stabilizing watercraft that are anchored or moving at low speed during “pre-anchor” operation. The requirements for stabilizing a watercraft moving at a relatively high speed, however, are different than (and conflict with) the requirements for stabilizing a watercraft moving slowly or not at all. Stabilizer fins optimized for driving/traveling operation preferably have a wide span and a short chord length relative thereto. Lifting forces for stabilizing the watercraft are produced by the oncoming/incident flow of water during travel and the angle of attack of the fin stabilizers. To minimize the required drive torque, (the torque required to maintain or change the angle of attack) the axis of rotation should be located in the vicinity of the center of lift of the fin stabilizer.
For pre-anchor stabilizing, on the other hand, there is no or negligible oncoming flow with respect to the stabilizer fins. Therefore, forces for counteracting a rolling movement must be generated by the fin stabilizers themselves, that is by moving the stabilizer fins to displace water and/or create a flow of water around the moved stabilizer fin. For a fin having approximately the same span width, stabilizer fins used for pre-anchor stabilizing should have a large chord length and an axis of rotation closer to the nose of the stabilizer fin. High drive torques are required in order to allow stabilizers adapted for pre-anchor operation to also be used to effectively counteract rolling movements of the watercraft in driving operation. Due to the large stabilizer fin and the requirement for a powerful drive, these stabilizer systems are heavy, consume a relatively large amount of power and occupy a large space in the watercraft. Furthermore, when designing fin stabilizers, a compromise must be made between optimizing the stabilizer for driving operation and optimizing the stabilizer for pre-anchor operation.
A fin including a variably adjustable outer contour is disclosed in U.S. Pat. No. 5,367,970 A. Control wires are integrated in the fin which change the curvature of the fin when their lengths change. The change in length is regulated by a control system.
A fin stabilizer for stabilizing a watercraft is known from DE 102011005313 B3. This stabilizer includes a main fin that is pivotable by a watercraft-side fin drive and a tail fin that is movably supported on the main fin. The fin stabilizer includes a locking device that actively regulates the pivoting of the tail fin. In pre-anchor operation the locking device blocks a possible pivoting movement of the tail fin and thereby increases the surface of the stabilizer fin. In driving operation the locking device is switched to free movement (unlocked) and makes possible a free pivoting movement of the tail fin so that the surface of the stabilizer fin is reduced.
These known concepts provide for a more effective stabilizing of watercraft than one-part stabilizer fins, in particular by adjusting the effective surface area of the stabilizer fins. However, in both cases an active regulating device is required to select between pre-anchor and driving operation states. Furthermore in DE 102011005313 the locking device includes of a variety of mechanical or hydraulic components.
U.S. Pat. No. 2,151,836 A discloses a boat including collecting surfaces for wave shocks as well as support surfaces that reduce the tendency of the bow to sink. Publication DE 60 2005 004 944 T2 discloses an active roll-stabilization system for ships. Stabilizing fins for damping the longitudinal movement of keel yachts are known from publication DE 39 39 435 A1.
One aspect of the present disclosure is to provide an improved fin stabilizer for a watercraft that effectively stabilizes a watercraft both in driving operation and in pre-anchor operation. Another aspect of the disclosure is to provide a watercraft that is highly stabilized against rolling movement both during pre-anchor operation and during driving operation.
A disclosed fin stabilizer for stabilizing a watercraft includes a main fin that is pivotable by a watercraft-side fin drive and a tail fin. The tail fin is elastically deformable if excessive water forces act thereon, that is, if water forces against the tail fin exceed a predetermined level. The water forces thereby automatically set a tail fin angle. Alternatively or additionally a connection body for automatically setting a tail fin angle can be disposed between the tail fin and the main fin, which connection body sets the tail fin angle based on a force of the water acting on the tail fin. Stated another way, the connection body varies the tail fin angle based on the force of water acting on the tail fin.
Both the flexible tail fin and the connection body for automatically setting a tail fin angle are passive, and thus control devices, active control systems and the like are not necessary. Active control devices do not need to be integrated in the fin stabilizer, which makes the fin stabilizer lighter and less complex than conventional fin stabilizers of the same size. Manufacturing and maintenance expenses are also significantly reduced. The flexible tail fin and/or connection body acts like a spring having a spring constant that is adapted to the forces that are expected to act on the stabilizer fin. In pre-anchor operation the effective surface area of the stabilizer fin is extended by the tail fin. This is because, in pre-anchor operation, the force acting on the tail fin when the fin drive operates produces little or no deflection of the tail fin. However, during driving operation a flow of water acts in addition to the fin drive, and the force of this water acting on the tail fin deflects the tail fin. The effective surface area of the stabilizer fin is thus reduced during driving operation. The drive torque of the stabilizer fin drops and thus a greater angle of attack and greater lifting force resulting therefrom for reducing rolling is achieved.
In one exemplary embodiment the tail fin is pivotably supported on the main fin for movement about a pivot axis. A defined mechanical pivoting of the tail fin is thus made possible. The connection body can thereby be an assembly of at least one elastic deformation body, a cylinder-piston assembly, a dual-action torsion spring seated on the pivot axis and the like, which passively adjust the tail fin angle and the pivoting of the tail fin.
According to a preferred exemplary embodiment of the fin stabilizer, the connection body includes a deformation body that at least partially connects the main fin to the tail fin. The deformation body is preferably comprised of a one-part elastic plastic, or an elastic combination of plastics and other suitable materials, and has a defined spring constant. The mechanical pivot axis between the tail fin and the main fin can thereby be completely replaced by the connection body.
In a further preferred exemplary embodiment of the fin stabilizer the deformation body is multi-part, for example, multi-layer. The individual bodies or layers can have different thicknesses, and the orientation of the layers can be selected based on the required properties of the deformation body. Reinforcing fibers can be embedded in the deformation body. The behavior of the tail fin can be precisely set by the composition of the deformation body and by the geometric shaping and the thickness or thickness distribution of the layers of the deformation body.
According to an advantageous exemplary embodiment the connection body includes at least one stabilizing element. This stabilizing element preferably limits the degrees of freedom for movement of the tail fin to those that are necessary for the operation of the fin stabilizer. In other words, the tail fin is only allowed to flex or pivot in a manner that improves stabilization, and movements that do not improve stabilization are reduced or substantially prevented. The stabilizing element thus acts like a pivot guide that prevents a twisting of the connection body. This stabilizer element is preferably incorporated in the center or in the neutral phase of the deformation body. The layer element can comprise, for example and without limitation, a plastic, a fiber composite material, a metal, or a metal hybrid material or the like.
In an advantageous embodiment of the fin stabilizer the stabilizing element at least sectionally connects the tail fin to the main fin. This ensures at least one continuous connection between the main fin and the tail fin, and the tail fin will still be reliably connected to the main fin even if the deformation body is damaged.
The securing element of the fin stabilizer preferably includes at least one web at least on one side thereof. This provides a planar rib-type bracing of the deformation body. Preferably a plurality of webs, in particular wall-type webs, are provided, and at least some intermediate spaces between the webs are filled with compressible and stretchable materials such as plastic foams. Furthermore, multi-part, in particular multi-layer deformation combinations and the like can be used in the intermediate spaces. This helps make possible a defined transmission to the deformation body of the forces acting on the tail fin. The spring constant of the deformation body can be precisely set via the materials in the intermediate spaces. However, the materials can also be chosen such that their influence on the spring constant is negligible compared to the influence of a central plane of the deformation body. For example, it may be desirable to choose the materials used in the intermediate spaces so that, depending on the pivot angle, differently-sized resistances must be overcome. Likewise the materials in the intermediate spaces can be chosen such that, depending on the pivot angle, an increasing resistance for pivoting the tail fin must be overcome. That is, the forces that must be overcome to pivot the tail fin may increase with increasing pivot angle.
In a further advantageous exemplary embodiment of the fin stabilizer, the connection body or the tail fin includes, at least in sections, a friction-fit and/or interference-fit connection to the main fin. The connection body also preferably transitions flush into the tail fin. This allows such a fin stabilizer to be manufactured with a high degree of automation utilizing common manufacturing processes. Screw connections and dovetail joints are examples. Alternatively or additionally the connection body can also be connected in a materially bonded manner, for example, adhered, to the main fin and/or the tail fin.
The connection body or the tail fin can extend flush or smoothly or in a stepwise manner from the main fin. In particular, a flow-optimizable shape of the fin stabilizer results from the flush design. Eddies in the transition regions between the main fin and the connection body and between the connection body and the tail fin can thus effectively be prevented. The manufacturing of the fin stabilizer can be simplified by the stepwise design.
A watercraft equipped with the disclosed fin stabilizer is characterized, in particular with a simplified fin stabilizer and by high roll stabilization, both in driving operation and in pre-anchor operation.
Preferred exemplary embodiments of the disclosure are explained in more detail with reference to the following greatly simplified schematic illustrations:
In the drawings, identical structural elements are identified by identical reference numerals. For clarity, in some Figures only some of the same structural elements are provided with a reference numeral.
The main fin 2 is driven via a drive shaft 7 by a conventional watercraft-side fin drive 42 of a conventional watercraft 40 (illustrated in schematically in
The main-fin-side connecting element 12, the deformation body 10 of the connection body 6, and the tail-fin-side connecting element (not illustrated) are configured to maintain a streamlined shape between the main fin 2 and the tail fin 4. An outer skin 14 covering the deformation body 10, the main-fin-side connecting element 12, and the tail-fin-side connecting element transitions flush or in a stepless manner from the main fin 2 to the tail fin 4.
A section through a second exemplary embodiment of the fin stabilizer 1, taken in the region of a connection body 6 for automatically setting a tail fin angle α between the tail fin 4 and the main fin 2, is shown in
Depending on the requirements for the multi-layer deformation body 10, the thickness, i.e. the extension in height direction z, of the stabilizing element 16 and of the individual layers 20, 21, 22, and 23 can vary. Likewise, the individual layers 20 to 23 can be comprised of different materials. The stabilizing element may be a rigid material, for example, a plastic-based fiberglass composite material; the two inner layers 22, 23 abutting directly on the stabilizing element 16 may be comprised, for example, of a polyurethane foam or polyethylene foam, and the two outer layers 20, 21 may be comprised, for example, of a non-foam polyurethane elastomer.
The stretchable and compressible layers 20, 21, 22, 23 are adapted to the stabilizing element 16 in terms of their thickness. The desired shape of the connection body 6 thus results, and thus also the shape of the transition from the main fin 2 to the tail fin 4. In the second exemplary embodiment the stabilizing element 16 tapers towards the tail fin. The inner layers 22, 23 increase in height in the tail fin direction, whereas the outer layers 20, 21 are tapered towards the tail fin to set the flow-optimized shape. Of course, other patterns are also possible.
An enlarged section of the region B from
The webs 24, 25, 26, 27 are wall-shaped and extend orthogonally from the stabilizing element 18 in the height direction z. They are each preferably uniformly spaced from one another in the longitudinal direction x of the fin stabilizer 1, and their heads or distal ends are spaced from the outer skin 14. Due to the flow-optimized shape of the deformation body 10, the webs or walls 24, 25, 26, 27 extend away from the stabilizing element 16 to different extents; that is, they have different lengths or heights. Due to the mutual spacing, a plurality of intermediate spaces 32, 33, 34, 35 are formed that connect to each other at the head side (distal ends) of the webs 28, 29, 30, 31. In this exemplary embodiment the intermediate spaces 32, 33, 34, 35 are filled with a plastic foam 22, 23. The stabilizing element 16 and the webs 28, 29, 30, 31 are also preferably comprised of plastic. For mutual dovetailing/meshing/engagement of the plastic material in the intermediate spaces 32, 33, 34, 35, the webs can also be provided with corresponding holes for receiving or permeation of the plastic material. Piercing be provided with the plastic material. During a deforming of the connection body 10 the webs 28, 29, 30, 31 of one side are moved towards each other at the head side, and the plastic material in the respective intermediate spaces 32, 33, 34, 35 is pressed together. This affects a pivoting behavior of the tail fin and allows this behavior to be adjusted.
A section through a connection body 6 for automatically setting a tail fin angle α between a tail fin 4 and a main fin 2 of a fourth exemplary embodiment of a fin stabilizer 1 is shown in
A section through a region of a sixth exemplary embodiment of the fin stabilizer is depicted in
The operation of the connection body 6 for the automatically setting a tail fin angle α will now be explained. This description relates to all fin stabilizers shown in
In pre-anchor operation the connection body 6 increases the effective surface area of the fin stabilizer 1 by an amount equal to the surface area of the tail fin 4, since the force acting on the tail fin 4 during a pivoting of the fin stabilizer 1 is not sufficient to significantly deflect the tail fin 4 by the tail fin angle +α, −α. In pre-anchor operation an effective surface area of the fin stabilizer 1 is formed by the main fin 2 and by nearly the entire surface of the tail fin 4. Stated another way, if the water force acting on the tail fin 4 is below a predetermined amount, for example when the watercraft is in pre-anchor operation, the connection body 6 having spring-like properties does not deflect the tail fin 4, and hence, generally maintains the tail fin 4 in its equilibrium state. In driving operation, however, the water flow also acts to drive the tail fin 4, so that force acting on the tail fin 4 deflects the tail fin 4 based on the direction of flow. The surface of the fin stabilizer 1 is thus reduced in driving operation so that the fin stabilizer 1 can be strongly deflected by the fin drive. In driving operation the tail fin 4 is thus effectively in free movement or free-floating, so that in driving operation the surface area of the fin stabilizer 1 is formed in largest part by the main fin 2.
A fin stabilizer 1 is disclosed for stabilizing a watercraft 40, which fin stabilizer 1 includes a main fin 2 that is pivotable by a watercraft-side fin drive, and a tail fin 4 that is movably supported on the main fin 2. The stabilizer 1 includes a connection body 6 for automatically setting a tail fin angle between the tail fin 4 and that main fin 2 based on a water force acting on a surface of the tail fin 4, as well as a watercraft that is stabilized by at least one such fin stabilizer 1.
Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved fin stabilizer.
Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.
All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.
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10 2014 217 227 | Aug 2014 | DE | national |
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Number | Date | Country | |
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20160059941 A1 | Mar 2016 | US |