NO20221267A1

NO20221267A1 - Adjustable foil mechanism

Info

Publication number: NO20221267A1
Application number: NO20221267A
Authority: NO
Inventors: Audun Yrke
Original assignee: Eitzen Rederi AS
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2024-02-12
Also published as: WO2024112202A1; NO347659B1

Description

Adjustable foil mechanism

Field of the invention

The invention relates to a foil mechanism for controllable adjustment of the rotational stiffness of a foil arranged on a marine vessel. The invention also relates to a method of assembling the foil mechanism.

Background

It is known to use one or more foils, also known as wings or fins, below the waterline to improve the stability and efficiency of aquatic vessels such as ships or boats. When the vessel is subjected to waves, the foils will typically reduce wave induced motions such as pitch and roll. The foils will also typically provide forward propulsion thus improving fuel consumption efficiency and speed of the vessel.

It is known that rotatable foils improve the performance, especially in low speed. An example of a rotatable foil is disclosed in the Japanese patent application JP61037593A.

Research has shown that spring-loaded foils can achieve the desired rotation. An issue has been how to adjust the rotational stiffness in order to work properly in a wide speed range.

When connecting rotatable foils to a vessel, it is key to adapt the rotational stiffness according to the speed of the vessel and sea conditions. When the speed increases, the stiffness should also increase to improve stability and efficiency.

It is a difficult task to obtain the desired range of rotational stiffness without overloading the mechanics at high stiffness. This is solved with the invention.

An object of the invention disclosed herein is to provide an efficient, simple way of adjusting rotational stiffness of foils at sea. Also, the invention provides a stable and durable solution for adjusting rotational stiffness of a foil.

Summary of the invention

The invention relates to a foil mechanism for any aquatic vessel such as a ship including a foil connected to the aquatic vessel in a position where the foil is at least partly submerged, a rotation axis, a longitudinal axis, a support structure located inside the foil and a cantilever beam connected to the aquatic vessel. The foil may be movably connected to the cantilever beam and the foil may be configured to rotate about the cantilever beam about the rotation axis.

The foil mechanism may include linear actuator for moving the foil relative to the aquatic vessel along the longitudinal axis for adjusting a hydrodynamic moment arm of the foil and means for adjusting the rotational stiffness of the foil.

The hydrodynamic moment arm may be adjusted independently of the rotational stiffness, and vice versa.

The invention further relates to said foil mechanism wherein the foil mechanism is configured to adjust the hydrodynamic moment arm and the rotational stiffness of the foil simultaneously.

The invention further relates to said foil mechanism, wherein the linear actuator comprises a motor, a drive shaft extending through the cantilever beam along its longitudinal axis, wherein the motor configured to drive the drive shaft. It may further include a rack connected to the support structure, a pinion connected to the drive shaft, wherein the pinion directly or indirectly engages the rack, wherein the support structure includes a number of guiding rails, a number of guide rail supports and a support seat.

The invention further relates to said foil mechanism, wherein the means for adjusting rotational stiffness of the foil comprises at least one bending rod fixed at one end to a connection point located at a surface of the support structure, wherein the bending rod extends longitudinally with respect to the foil, and wherein the bending rod is connected to the cantilever beam.

The invention further relates to said foil mechanism, wherein the cantilever beam comprises at least one internal bore, wherein each bending rod extends through each respective bore at least partly through the cantilever beam.

The invention further relates to said foil mechanism, wherein the internal bore runs laterally through the longitudinal centre axis of the cantilever beam, and wherein the drive shaft extends longitudinally through the cantilever beam at a distance from the longitudinal centre axis of the cantilever beam, thereby avoiding collision with the internal bore.

The invention further relates to said foil mechanism, wherein the linear actuator is a hydraulic or pneumatic system comprising a hydraulic or pneumatic piston, or wherein the linear actuator is a winch-based system comprising a wire or cable. Optionally the linear actuator is driver by a power screw.

The invention further relates to said foil mechanism, wherein the foil mechanism is connected to the hull of an aquatic vessel or to a support structure of an aquatic vessel.

The invention further relates to said foil mechanism, wherein the cantilever beam is provided with a base plate on its root end.

The invention further relates to a method of assembling said foil mechanism, comprising the step of inserting the support structure into the foil, and mounting the foil to the hull or to a support structure of the aquatic vessel.

The invention further relates to a method of assembling said foil mechanism, wherein the cantilever beam is connected to the foil before the foil is connected to the aquatic vessel.

The invention further relates to a method of assembling said foil mechanism, comprising the step of connecting the base plate and/or the cantilever beam to the hull, mounting the guide rail supports including the support seats to the support frame, mounting the support frame onto the cantilever beam, optionally rotating the support frame to access all bolt holes of the base plate, mounting the bending rods to the support frame and the cantilever beam, and mounting the foil onto the support frame.

List of figures

Fig. 1A is a side view of a foil according to the invention connected to a ship;

Fig. 1B is an elevation of two foils according to the innovation mounted to opposite sides of a bow portion of a ship;

Fig. 2 is a partly transparent perspective view of a foil according to the invention; Fig. 3A is a cross-sectional side view of a foil according to the invention where the foil is adjusted for low speeds;

Fig. 3B is a cross-sectional side view of a foil according to the invention where the foil is adjusted for high speeds;

Fig. 4A is a transparent perspective view of the tip side of foil according to the invention;

Fig. 4B is a perspective view of the root side of foil according to the invention;

Fig. 5A is a perspective view of a ship with a foil support structure connected to the bow; and

Fig. 5B is a perspective view of a ship showing a possible location for a foil according to the invention.

Detailed description of embodiments

Fig. 1A is a side view of a foil 16 according to the invention connected to a ship 10.

The foil 16 is an elongate member adapted to stabilise the ship, reduce vessel motion in waves, and to provide forward propulsion.

The foil 16 may be mounted directly to the ship, e.g., to the hull of the ship. The foil 16 may also be mounted indirectly to the ship, e.g., to an intermediate structure connected to the ship.

Fig. 5A and 5B shows examples of how a foil 16 of the invention can be connected to a ship 10.

Fig. 5A is a perspective view a ship 10 with a foil support structure 120 connected to the bow of a ship. Fig.5B shows another possible location for a foil 16 according to the invention.

In Fig.5A, two foils are mounted on each side of an intermediate support structure 120. The support structure 120 may be mounted to the ship at any location.

In Fig.5B two foils 16 are mounted directly to the ship 10, more specifically to the bow.

As seen in Fig.1A, the foil 16 may be mounted at a bow portion 12 of the ship 10 but may also be mounted at an aft portion, midship or under the ship. The foil 16 is typically mounted at a location where it is at least partly submerged below the waterline, or at a location where the foil 16 eventually may become at least partly submerged, for it to interact with water.

The foil 16 has a forward edge 26 facing forward and an aft edge 28 facing aft. A longitudinal axis L (see Fig.2) of the foil 16 extends between the aft edge 28 and the forward edge 26.

Fig. 1B is an elevation of two foils 16 according to the innovation mounted to opposite sides of a bow portion 12 of a ship.

In Fig.1B two foils 16 are arranged on opposite sides of the bow portion 12 of the ship and extends substantially perpendicularly away from the hull.

The foil 16 has first and second ends known as the root 18 and the tip 20. The foil 16 is connected to the hull or support structure 120 (see Fig.5A) at the root 18 side. A lateral axis of the foil 16 extends from the root 18 to the tip 20.

The lateral axis of the foil 16 is aligned parallel with the rotation axis R (see Fig.2).

Each foil 16 has a forward edge 26 facing forward and an aft edge 28 facing aft.

A winglet (not shown) may be provided at the tip 20 of the foil 16 and extends substantially perpendicular thereto.

Fig. 2 is a partly transparent perspective view of a foil 16 according to the invention.

The foil 16 comprises a cavity (not shown) on the root 18 side of the foil 16 facing the hull or support structure 120 (see Fig.4A) of the ship (not shown). The cavity is provided for housing internal components of the foil 16 according to the invention. This cavity is better illustrated in Fig.4B.

The foil 16 may include a support frame 30 located within the cavity of the foil 16. The support frame 30 may be shaped as a cubical housing. The support frame 30 surrounds an inner volume. The support frame 30 is preferably elongated.

The support frame 30 and other components connected to the support frame 30 can be easily inserted into and extracted from the cavity of the foil 16.

The support frame 30 comprises a rear surface 32 facing the forward edge 26 and a front surface 42 facing the aft edge 28.

The foil 16 further includes connection means for rotatably and movably connecting the foil 16 to the ship. The foil 16 may rotate about a rotation axis R and relative to the hull or support structure (not shown) and move along a longitudinal axis L and relative to the hull or structure.

The connection means may comprise a cantilever beam 40 (see also Fig.4A and 4B) having a base plate 36 for fixing the cantilever beam 40 to the hull or support structure. The cantilever beam 40 may also be fixed to the hull or support structure directly.

The foil 16 may rotate about the cantilever beam 40 and is thereby rotatably connected to the cantilever beam 40.

The cantilever beam 40 is preferably cylindrical and strong enough to carry the weight of the foil 16, and to withstand the hydrodynamic forces and moments imposed on the cantilever beam 40 by the foil 16 in rough sea.

The support frame 30 is configured to receive the cantilever beam 40.

The support frame 30 includes lower guide rails 442 and upper guide rails 440 extending longitudinally. Preferably there are two lower guide rails 442 arranged with a distance between them, and two upper guide rails 440 spaced apart with the same distance.

The cantilever beam 40 is equipped with rail supports 480, 482 (see Fig.3A and 4A) for slidably connecting the cantilever beam 40 to the guide rails 440, 442. Each rail support 480 is connected to a support seat 484 (see Fig.3A) to which the outer surface of the cantilever beam 40 seats against. Each support seat 484 has a rounded shape corresponding to the cylindrical shape of the cantilever beam 40. When the foil 16 rotates, the support seat 484 is free to move around the outer surface of the cantilever beam 40 and vice versa.

The foil 16 may further include a rack and pinion system for moving the foil along its longitudinal axis L relative to the hull or structure. The foil 16 may include any conventional linear actuator system and is not limited to rack and pinion systems. Examples may be systems actuated by a hydraulic piston, pneumatic piston, a wire, or any other conventional mechanism for linear movement. A mechanical system comprising a power screw may also be used.

In case a rack and pinion system is used, the support frame 30 may include a rack 34 (see also Fig.4A) extending between the rear surface 32 and the front surface of the support frame 30, the teeth of the rack preferably facing upwards. A motorized pinion 340 is connected to the cantilever beam 40. The pinion 340 is rotated by a drive shaft 342 (see Fig.3A) located inside the cantilever beam 40. The drive shaft 342 extends through the cantilever beam 40 in parallel with the rotation axis R. The drive shaft 342 is driven by a motor (not shown).

Fig. 3A shows a cross-sectional view of the drive shaft 342.

The rack 34 teeth are located below the rotation axis R. The pinion 340 may be connected to an auxiliary gear 341 as shown in Fig.4A to transfer rotation of the pinion 340 down to the rack 34. The rotation axis of the auxiliary gear 341 coincides with the rotation axis R so that the rack 34 may rotate relative to the cantilever beam 40 while at the same time keeping the auxiliary gear 341 engaged with the rack 40 at all times.

The motor (not shown) which drives the drive shaft 342 and the pinion 340 may be integrated within the cantilever beam 40, or it may be located inside the hull of the ship or inside the support structure 120 (see Fig.5A) for easy access and protection from seawater.

The foil 16 may rotate about the longitudinal axis of the cantilever beam 40 which coincides with the rotational axis R of the foil.

In summary the support frame 30 provides a supporting housing or framework connected to the inside of the foil 16 for carrying or supporting transport means for the foil 16 to move back and forth along its longitudinal axis.

Fig. 3A is a cross-sectional side view of a foil 16 according to the invention where the foil 16 is adjusted for low speeds.

The cross-section shown is cut through a middle of the cantilever beam 40.

In an embodiment the foil 16 may be constantly spring loaded by a spring mechanism (not shown) providing a constant spring force which is not adjustable. In this embodiment the foil 16 may still include a linear actuator for adjusting the hydrodynamic moment arm HDM.

In another embodiment the foil 16 may be spring loaded by an adjustable spring mechanism (not shown). In this embodiment the foil 16 may still include a linear actuator for adjusting the hydrodynamic moment arm HDM. The spring mechanism may be adjustable completely independently with regards to the linear actuator, i.e., the linear actuator does not affect the rotational stiffness of the foil.

The foil 16 may include means for adjusting rotational stiffness as follows.

At least one flexible bending rod 600 is provided. The bending rod 600 may be fixed, pinned or rotatably connected to the rear surface 32 of the support frame 30 at a connection point 610. This is also shown in Fig.4A.

The bending rod 600 may be free to rotate at the connection point 610, or it may be completely fixed. The bending rod 600 is preferably connected to the rear surface 32 at the connection point 610 so that axial movement is prevented.

The bending rod 600 extends longitudinally from rear to front of the support frame 30. The bending rod 600 is preferably not fixed in its opposite end and is free to move along the length of the ship.

The cantilever beam 40 includes an internal bore 630 extending laterally through the centre of the cantilever beam 40. The bore 630 is configured to receive the bending rod 600 through an entry point 700. The bending rod 60 is free to move axially inside the bore 630 along its length.

The drive shaft 342 conveniently runs through the cantilever beam 40 a distance away from the centre of the cantilever beam 40 so that the drive shaft 342 does not collide with the bore 630.

Fig. 4A is a perspective view of the foil 16 according to the invention. Fig.4A illustrates how a plurality of bending rods 600 may be provided next to each other although only one bending rod 600 is shown. In Fig.4A three bores (not shown) are provided – sees only three entry points 700 in this figure. The embodiment of Fig. 4A therefore has the capacity to carry three bending rods 600.

The bending rod 600 is preferably longer than the travel length of the cantilever beam 40 relative to the support frame 30 so that each bending rod 600 always runs at least partly through the bore 630.

The bending rod 600 acts as a spring which provides rotational resistance, a counter torque or rotational stiffness to the foil 16 which is free to rotate around the cantilever beam 40. The bending rod 600 also functions as a cantilevered beam itself with an at least partly rotatably support end and a free end. The rotational stiffness of the foil 16 will naturally depend on the thickness, profile, and material properties of the bending rod 600. The bending rod may be of any suitable material such as metal, plastic, or composite. Preferably the bending rod is made of steel 600. Corrosion protection may be applied.

The cantilever beam 40 is fixed while the foil 16 is free to rotate. The bending rods 600 will provide rotational resistance when the foil 16 rotates. When the foil 16 rotates a moment arm M emerges/is provided between the support end 610 and the entry point 700.

Since the foil 16 includes a transport means the moment arm M may be adjusted. When this moment arm M is reduced, the rotational stiffness is increased. A high rotational stiffness is preferred in high speeds and a light rotational stiffness is preferred for low speeds.

Fig. 3B is a side view of a foil 16 according to the invention where the foil 16 is adjusted for high speeds.

The cantilever beam 40 which is fixed to the hull or support structure of the ship includes a motorized pinion 340 (see Fig.2). The drive shaft 342 which rotates the pinion 340 is shown in Fig.3A. The drive shaft 342 extends longitudinally inside the cantilever beam 40 from a motor (not shown) and is aligned eccentric and parallel with respect to the centre of the cantilever beam 40. Therefore, the drive shaft 342 may extend above the bending rod 600 though the tip of the cantilever beam 40 where the pinon 340 is located.

Essentially, the linear actuation system described provides the ability to move the foil 16 back and forth while the ship is at sea and while the ship alters speed.

When the ship propagates forward, or even when the ship lies still, a hydrodynamic load is imposed on the foil 16 due to waves and/or the motion of the ship. A hydrodynamic lift centre HDLC perpendicular to foil 16 emerges. A hydrodynamic moment arm HDM is therefore provided between the rotation axis R and the hydrodynamic lift centre HDLC.

When the pinion 340 is actuated the cantilever beam 40 moves along the rack 34 (see Fig.2). When the pinion 340 moves the cantilever beam 40 towards the rear surface 32 the distance between the entry point 700 and the connection point 610 is reduced. This decreases the hydrodynamic moment arm HDM, and the hydrodynamic moment arm HDM simultaneously as the moment arm M decreases. This has the technical effect that the hydrodynamic loading is decreased simultaneously as the rotational stiffness of the foil 16 increases. This provides a rigid foil better suited for high-speed conditions. Moving the foil 16 in the opposite direction has the opposite effect and provides a slack foil best suited for low-speed conditions or while the ship lies still.

The foil mechanism allows the foil 16 to carry a higher hydrodynamic force (lift) in high speed without overloading the bending rods 600, since the hydrodynamic moment the bending rod 600 must withstand is reduced as the HDM is decreased.

This allows for a large range of rotational stiffness while keeping the load on the bending rod 600 at a moderate level.

The ability to adjust rotational stiffness and hydrodynamic loading on the foil 16 provides a flexible mechanism for adjusting the ship stability at sea depending on the ship speed and sea conditions.

Fig. 4A is a transparent perspective view of the tip 20 side of foil 16 according to the invention. Fig.4A shows how a rack and pinion system may be provided inside the foil.

Fig. 4B is a perspective view of the root 18 side of foil 16 according to the invention. Fig.4B reveals how the root side of the cantilever beam is connectable to the ship or a support structure, preferably by bolts as indicated in the figure. Fig. 4B also shows how the cavity of the foil 16 provides a compartment wherein the support frame 30 may be inserted.

Claims

PATENT C LAIMS

1. Foil mechanism for aquatic vessels (10) comprising:

a foil (16) connected to the aquatic vessel (10) in a position where the foil (16) is at least partly submerged;

a rotation axis (R);

a longitudinal axis (L);

a support structure (30) located inside the foil (16);

a cantilever beam (40) connected to the aquatic vessel (10);

wherein the foil (16) is movably connected to the cantilever beam (40) and wherein the foil (16) is configured to rotate about the cantilever beam (40) about the rotation axis (R);

a linear actuator for moving the foil (16) relative to the aquatic vessel (10) along the longitudinal axis (L) for adjusting a hydrodynamic moment arm (HDM) of the foil (16);

means for adjusting the rotational stiffness of the foil (16).

2. Foil mechanism according to claim 1, wherein the foil mechanism is configured to adjust the hydrodynamic moment arm (HDM) and the rotational stiffness of the foil (16) simultaneously.

3. Foil mechanism according to any preceding claim,

wherein the linear actuator comprises;

a motor;

a drive shaft (342) extending through the cantilever beam (40) along its longitudinal axis;

the motor configured to drive the drive shaft (342);

a rack (34) connected to the support structure (30);

a pinion (340) connected to the drive shaft (342);

wherein the pinion directly or indirectly engages the rack (34);

wherein the support structure (30) includes a number of guiding rails (440, 442) a number of guide rail supports (480, 482) and a support seat (484) for supporting the cantilever beam (40).

4. Foil mechanism according to any preceding claim, wherein the means for adjusting rotational stiffness of the foil (16) comprises:

at least one bending rod (600) fixed at one end to a connection point (610) located at a surface (32) of the support structure (30);

wherein the bending rod (600) extends longitudinally with respect to the foil (16); and

wherein the bending rod (600) is connected to the cantilever beam (40).

5. Foil mechanism according to claim 4, wherein the cantilever beam (40) comprises at least one internal bore (630), wherein each bending rod (600) extends through each respective bore (630) at least partly through the cantilever beam (40).

6. Foil mechanism according to claim 5, wherein the internal bore (630) runs laterally through the longitudinal centre axis of the cantilever beam (40), and wherein the drive shaft (342) extends longitudinally through the cantilever beam (40) at a distance from the longitudinal centre axis of the cantilever beam (40), thereby avoiding collision with the internal bore (630).

7. Foil mechanism according to claim 4 or 5, wherein the linear actuator is a hydraulic system comprising a hydraulic piston; or

a pneumatic system comprising a pneumatic piston; or

a winch-based system comprising a wire or cable; or

a mechanical system comprising a power screw.

8. Foil mechanism according to any preceding claims, wherein the foil mechanism is connected to the hull of a aquatic vessel (10) or to a support structure (120) of a aquatic vessel (10).

9. Foil mechanism according to any preceding claims, wherein the cantilever beam (40) is provided with a base plate (36) on its root end.

10. Method of assembling a foil mechanism according to any preceding claims, comprising the step of:

- inserting the support structure (30) into the foil (16); and

- mounting the foil (16) to the hull or to a support structure of the aquatic vessel (10).

11. Method of claim 10, wherein the cantilever beam (40) is connected to the foil (16) before the foil (16) is connected to the aquatic vessel.

12. Method of claim 10 or 11 for assembling a foil mechanism according claim 9, comprising the step of:

- connecting the base plate (36) and/or the cantilever beam (40) to the hull;

- mounting the guide rail supports (480, 482) including the support seats (484) to the support frame (30);

- mounting the support frame (30) onto the cantilever beam (40);

- optionally rotating the support frame (30) to access all bolt holes of the base plate (36);

- mounting the bending rods (600) to the support frame (30) and the cantilever beam (40); and

- mounting the foil (40) onto the support frame (30).