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Title:
SIDE LIST STABILIZING SYSTEM AND VESSEL INCORPORATING SAME
Document Type and Number:
WIPO Patent Application WO/2010/050905
Kind Code:
A2
Abstract:
A side stabilizer and a wind-powered vessel incorporating same is designed in a way that both lateral sides (1) of the vessel's hull (2) are equipped with at least one fin (3) positioned above the waterline if the vessel is fully loaded and stationary. A preferably flat shaped fin (3) obliquely rises in relation to the waterline (4), so that the distance between the part of the fin near the bow (5) and the waterline is bigger than the one of the fin part near the stern (6). Both sides (1) of the vessel (2) are equipped with at least one (3), preferably two (3 and 3a) longitudinal fins. When a sailing boat is in its upright position and fully loaded, both fins are entirely above the water surface (4), but when it starts heeling or leaning according to its longitudinal axis (9) the fins on the lee side of the vessel partly or completely submerge. That is how they provide additional hydrodynamic buoyancy that balances the vessel. This kind of device or utensil reduces the vessel's transversal listing which the vessel is exposed to due to side wind force, which results in improvement of the efficiency of the keel weight (7), better buoyancy of the vessel's hull, better wind force efficiency and consequently faster sailing. When sailing with the wind and approximately crosswise to wave direction, the utensil stabilizes the vessel's longitudinal movement since it reduces the vertical movement of the bow (5). When attached longitudinally to both sides of the hull, the side stabilizer fins additionally protect and strengthen the skin of the hull.

Inventors:
GROM, Tomaz (Trzaska 35, 1360 Vrhnika, SI)
Application Number:
SI2009/000059
Publication Date:
May 06, 2010
Filing Date:
October 27, 2009
Export Citation:
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Assignee:
GROM, Tomaz (Trzaska 35, 1360 Vrhnika, SI)
International Classes:
B63B39/06
Foreign References:
US3162167A1964-12-22
US3361104A1968-01-02
US5205235A1993-04-27
US5713297A1998-02-03
Other References:
None
Download PDF:
Claims:
Claims

1. A device for counteracting the vessel's side inclination due to the wind force in the sails (8), characterized in that each lateral side (1) of the vessel's hull (2) comprising at least one fin (3) above the waterline (4) when the vessel is stationary and fully loaded, wherein the fin's (3) shape is hydrodynamic and flat, particularly in the shape of the crescent moon and obliquely runs in direction of the sailing in relation to the waterline (4), rising from the stern (6) to the bow (5), so that the position of the fin near the bow (6) is higher than the position of the fin near the stern (6) in relation to the waterline (4).

2. A device as claimed in claims 1 and 2, characterized in that the particular construction on each lateral side (1) of the vessel's hull (2) comprising two fins (3 and 3a) which run vertically and longitudinally in relation to each other, so that the front part of the lower fin

(3) is closer to the bow (5), while the last part of the upper fin (3a) is closer to the stern (6) in relation to the other mentioned fin, wherein both fins longitudinally cover each other and are at the same time positioned on the side of the vessel's hull in a way that their position and shape does not expand the width of the vessel.

3. A device as claimed in claims 1 to 3, characterized in that the particular construction comprising the angles of the longitudinal incline of both fins (3 and 3a) being particularly different, wherein the incline of the lower fin (3) in relation to the waterline is smaller and generally from 0 to 5 degrees of arc, particularly 2 degrees of arc, while the incline of the upper fin (3a) in relation to the waterline is larger and generally from 0 to 7 degrees of arc, particularly 3 degrees of arc.

4. A device as claimed in claims 1 to 4, characterized in that the fins (3 and 3a) in particular construction are mounted to the hull (2) under different transversal angles, more precisely under such an angle (Fig. 4 - δ in γ) that when the vessel rotates due to the listing or side swaying, each fin in its widest part when touching the waterline sinks at an angle between minus 10 to 10 degrees arc, in particular at zero degrees.

5. A device as claimed in claims 1 to 5, characterized in that the fins (3 and 3a) are particularly a constituent part of the hull, but can be also either removable or even adjustable.

Description:
Side List Stabilizing System and Vessel Incorporating Same

Background Information of the Invention Subject Invention

The subject invention is a stabilizer for counteracting listing or side swaying and longitudinal movement of the vessels, especially single hulled which are mainly wind-powered. According to international patent classification this type of invention belongs to the field of equipment for ships or other waterborne vessels with further classification according to construction details to the field of inventions that decrease adverse vessel movements, especially to those that by using stabilizing foils act on ambient water.

Field of Application

Brief Description of the Technical Problem

The basic objective of the present invention is to provide a stabilizing system having the capability of counteracting vessel's roll and/or list or side sway conditions, which will help reduce the vessel's transversal listing or rotation around the longitudinal axis due to the side wind force in the sails, reduce the vessel's longitudinal movement when sailing approximately crosswise to wave direction and at the same time strengthen the construction of the hull, which will more efficiently tolerate torsion and friction loads which the vessel is exposed to while sailing or when moored.

Present Solutions to the Problem

Present solution for counteracting the vessel's listing, which is the result of the side wind force in the sails (8), is the centrally positioned keel which with its weight (7) stabilizes the vessel and prevents it from listing too heavily. With appropriate weight rearrangement the centre of gravity for the whole vessel lowers. This increases the vessel's stability. Equalization force depends on the relation between the mass of the part of the vessel in the water (2), the keel mass ballast (7) and the distance between the ballast mass and the part of the vessel's hull which is in the water. Larger the distance between the ballast mass and the buoyancy part of the vessel, greater the impact on the stability of the vessel. However, the distance between the part of the vessel which is in the water and the ballast mass, or in other words the keel length connected to the draft of the vessel's hull (7), can not go beyond certain limits. For greater impact on the stability of the vessel without changing the relation between the mass and the draft, a new device has to be adopted. The aim of the invention is to construct the vessel with a build in stabilizer.

Solution to the Problem

Technical problems described above are solved by innovative device whose basic characteristic is that both sides (1) of the vessel's (sailing boat's) hull (2) are equipped with at least one (3), particularly two (3 and 3 a) longitudinal fins. When the sailing boat is in its upright position and when fully loaded, both fins are entirely above the water surface (4) and do not increase front resistance while sailing.

When the wind force, which blows approximately in the horizontal direction and at least approximately transversally according to the longitudinal axis of the vessel, reaches the sails and the mast, the vessel turns around its longitudinal axis and the keel (7) mass consequently deviates from the vertical to oblique position. Deviation creates a lever arm which with the weight of the keel creates torque. That is why the vessel tends to turn around the longitudinal axis back to the starting point. With smaller deviation the lever arm is less noticeable and consequently also the torque is correspondingly smaller, which with sine dependence of the inclination angle considerably increases only with bigger keel deviation. Consequently the pitch around the longitudinal axis even when used only in normal weather conditions is relatively big and thus the vessel is less comfortable for the crew. For horizontal vessel's movement the side stabilizer (3 and 3a) provides extra hydrodynamic buoyancy on the lee side of the vessel (1) which helps static buoyancy force, the hull of the vessel, lift the lee side (1) and more quickly balance the vessel since it impacts on the size of the lever arm between the buoyancy and the submerged part of the vessel.

When a sailing boat starts heeling (it leans aside) under wind pressure (1), the lowest part of the lower fin (3) on the lee side of the vessel touches the water surface (4) and starts creating hydrodynamic buoyancy which lifts the vessel on this part and creates rotation (Fig. 3 - Fr 2) around longitudinal axis (Fig. 3 - 9) which is opposite to the direction of the rotation (Fig. 3 - FrI) created by the wind force in the sails (8). The more the vessel heels, the bigger surface of the stabilizer fins (3 and 3a) dives into the water. This increases the hydrodynamic buoyancy and consequently also the force of balancing the vessel (Fig. 3 - Fr 2). While the stabilizer creates buoyancy on the lee side outside the vessel's hull, the keel weight (7) pushes the windward side downwards. That is how the angle between the lifting part of the vessel and the immerse ballast part (Fig. 3 - β) considerably increases (Fig. 3 - α). This results in the improvement of the efficiency of the keel weight (7), higher comfort, better buoyancy of the vessel and better wind force efficiency. By increasing the horizontal speed of the vessel also the equalization force (Fig. 3 - Fr 2) of the vessel increases with the surface of submerged fin part remaining the same (3 and 3a). Hydrodynamic buoyancy is proportionally constant to the speed of the vessel, the speed of the vessel is proportionally constant to the covered wind force, the covered wind force is proportionally constant to the straight upward position of the sails (8), and the straight upward position (8) is proportionally constant to the force that balances the vessel. All the forces support and balance each other at higher final speed as the one achieved by the existing technology. This is the first aim of this innovation.

When sailing with the wind and approximately perpendicular to the waves, a vessel is exposed to high longitudinal wave movements. Especially dangerous and unpleasant is the vertical movement of the bow (5), which because of its wedge shape sinks deep into the water and then because of the buoyancy force also lifts very fast. This has negative effects on the sails (8), makes steering of the vessel more difficult and consequently provides less comfort when sailing. The vessel's behavior is similar to that of the car with springs without hydraulic buffer. In such sailing conditions, the front part of the side stabilizer fins (3) plays an important alleviation role; while the bow (5) wants to overly dip into the water, the front fins (3) slow down the movement and when it rises out of the water, the water on the upper surface of the fins prevents rapid lifting of the bow (5). This way sailing is more peaceful, more stable and safer than the one with existing technology.

The skin of the hull is attached to the inner structure of the vessel, which in the longitudinal direction consists of the keel and in the transverse direction of the vertically positioned vessel's ribs. The external skin side is unprotected and therefore quite vulnerable. By adding side stabilizer fins (3 and 3a), the structural strength of the hull significantly increases and the vessel's sensitivity to rigid objects (e.g. other vessels, floating objects and even the shore) reduces greatly. The reason for this is that the side fins junction is not made in straight line, but in an arc, giving the junction and consequently the whole fin incredible strength and resilience to mechanical load.

A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: > Fig. 1 A lateral view of the vessel incorporating the view of the stabilizer fins in its longitudinal direction rising from the stern to the bow in relation to the water surface and the position of the fins when the vessel is in the straight upright position.

> Fig.2 A side view of the vessel incorporating the view of the longitudinal and elevation overlap of the fins and the view of the hydrodynamically shaped construction of the fins in the shape of the crescent moon.

> Fig.3 A front view of the vessel incorporating the display of the effects of the side wind force and of the opposite force effects - of the vessel's balance force - which is caused by the lever arm between the buoyancy and submerged part of the vessel.

> Fig. 4 A cross-section of the vessel incorporating the display of different side inclinations of the stabilizer fins in relation to the horizontal surface.

> Fig. 5 A view of the inclined vessel from the back lateral side.

> Fig. 6 A view of the vessel in straight upright position from the back part of the vessel

(from the stern).

> Fig. 7 An overhead view of the hull incorporating enlarged display of the width and of the overlap of the stabilizer fins.

> Fig. 8 A bottom-up view of the vessel from the vertical perspective incorporating the overlap of the stabilizer fins.

A device for counteracting the vessel's side inclination due to the wind force in the sails (8) is designed in a way that both lateral sides (1) of the vessel's hull (2) have at least one fin (3) that is positioned above the static water level (4). A particularly flat shaped fin (3) obliquely rises in relation to the waterline (4), so that the distance between the part of the fin near the bow (5) and the waterline is bigger than the one of the fin part near the stern (6). A particular construction consists of two fins (3 and 3a) on each lateral side (1) of the hull (2), which are attached to the side of the hull in sufficiently large vertical distance to avoid excessive liquid friction (pipe effect) if both fins are immersed in the water. The fins are also longitudinally shifted, so that the beginning of the lower fin (3) is nearer to the bow (5), while the end of the upper fin (3a) is nearer to the stern (6) in comparison to the other fin. When viewed from above, both fins particularly cover each other in a certain, in particular bigger part. The angles of the longitudinal inclination of both fins from the stern to the bow are particularly different. When the vessel is stationary, the lower fin particularly rises for 2 degrees arc from the stern to the bow, while the upper fin (3 a) rises for particularly 3 degrees arc.

The fins (3 and 3 a) are in order to expand dynamic buoyancy constructed according to aerodynamic or hydrodynamic principles. Next to the sail geometry, the mast and the keel (7) also position of both fins (3 and 3a) on the lateral side (1) of the vessel plays an important role for defining sailing and other characteristics of the sailing boat. Also dimension of the fins contributes to aforementioned characteristics, which is the subject of the known vessel construction.

A particularly double fin construction of the stabilizer consists of the longitudinally shifted and in different levels attached fins (3 and 3a), so that they partly overlap each other when viewed from above. Such a layout allows a large fin surface to get in touch with the water, even with only slightly increased width of the vessel.

Next to longitudinal inclination the fins (3 and 3 a) are inclined also in transverse direction, under such an angle (Fig. 4 - δ and γ) that when the vessel rotates due to the listing or side swaying, each fin in its widest part when it gets in touch with the waterline sinks at a zero degree angle. This kind of arrangement enables the best possible hydrodynamic effect, smoother sailing in turbulent waters and effective protection against the waves splashing on deck.

The side stabilizer is made of one or multiple fins. According to proposer's opinion a stabilizer with two fins is the most appropriate variant (Figure 4). This variant has the fins mounted on two different levels. They partially cover one another when viewed from above (a bird's-eye view). Such a layout allows a large fin surface to get in touch with the water, even with only slightly increased width of the vessel (Figure 8).

The upper description of the angle settings refers to the fins cut out of a flat board, or in other words cut out in a single level. If the fin mounting is adjustable, so that when the vessel's list angle increases, each part of the fin sinks precisely at a zero degree angle in relation to the waterline, the stabilizing effect will even be greater. However, this kind of construction is technologically much more complicated, more expensive and consequently not considered a rational economical choice. When the vessel is stationary or motor-sails in calm waters the fins do not touch the waterline and therefore do not increase frontal fluid resistance or drag. Fins are in particular mounted so high that their lowest part does not touch the water until the vessel's transverse list angle reaches 1 degree or more.

The fins do not have to float on the water. Due to the frontal resistance and the turbulence of the ambient water, fins have to be as thin as possible, but at the same time still thick enough to ensure sufficient transversal strength. They have to ensure sufficient frictional strength on the outer edge to endure direct contact with the shore or other vessel's fenders, which means that they, or at least their leading edge, have to be made of suitable materials that can also be replaced if worn out (e.g. a grooved rubber band). Because of the changed vessel's side it is also advisable to change the form and the hardness of side fenders, which should have a score so that the fenders can fix themselves on the fins and consequently strengthen the construction. However, this is not the subject of this invention.

In accordance with the invention the fins are particularly constructed as a constituent part of the hull. However, they can also be constructed differently: they can be either removable or even adjustable.

It is understood that on the basis of this invention an expert from this field can design different constructions than mentioned above without circumventing the invention characteristics that are defined in the following patent claims.