Patent Grant
8973513
1. Technical Field
The present invention relates to craft, in particular water craft, ballast systems and systems for the rapid filling and emptying of ballast systems.
2. Description of the Related Art
In many water borne activities, water crafts, such as jet boats and rescue craft, are used to move people and/or objects across the water. The agility and power of such smaller vessels make them attractive for water-sports enthusiasts and thrill-seekers, for example. However, they may be generally unsuitable for military use as they may not be adapted for long deployment, nor be adapted to cope with the various weather conditions prevalent at sea.
The speed at which smaller craft can travel makes them comparatively less stable than larger craft, such as navy frigates and destroyers, especially in rough water. As a craft increases its velocity, the chance it will capsize can increase. This is particularly the case for jet boats and other forms of speed boat, and the capsized craft can be very difficult to ‘right’—return to an upright position—in order to continue moving.
Devices have been designed to improve the stability of the craft in the water, such as canting keels, which comprise a torpedo shaped ballast body at the tip of an aerofoil. The moment of the ballast body on the aerofoil is generally greater than that of the craft, and capsizing is thereby prevented. However, when travelling normally, the ballast is a deadweight which slows the craft, and such designs are generally impractical for use in faster boats, such as jet boats, as they reduce the speed and agility which make those craft attractive to use. Few practical designs are capable of preventing capsizing.
It is, therefore, generally desirable to provide a craft that is capable of righting.
Furthermore, it is generally desirable to overcome or ameliorate one or more of the abovementioned difficulties, or at least provide a useful alternative.
In accordance with the invention, there is provided a craft including:
a body having a front end, a rear end, two sides running between said ends, and an axis running generally from the rear end to the front end; and
a water displacement system operable to displace water to propel the craft across water, and to displace water to cause the craft to rotate about axis.
Preferably, the water displacement system includes a drive propulsion system for displacing water to propel the craft across water and a rotate propulsion system for displacing water to cause the craft to rotate about said axis.
Preferably, the rotate propulsion system includes a plurality of water propulsion systems arranged to generate rotation of the craft about the axis when actuated simultaneously.
The present invention also provides a ballast system for a craft, including a ballast tank capable of being at least partially filled with ballast to change a position of a center of gravity of the craft to assist in rotation of the craft when capsized.
Preferably, the ballast tank includes a bottom ballast tank capable, when in use, of being at least partially filled to draw the center of gravity of the craft towards the bottom of the craft to assist in rotation of the craft when capsized.
Preferably, when in use, the bottom ballast tank occupies substantially all of the internal volume of the craft.
Preferably, the ballast system is adapted to reduce torque required to right fife craft by filling the ballast tank from one end of the craft only.
The present invention also provides a rapid filling and emptying system for a ballast system of a craft, which craft includes a water displacement system, wherein said rapid filling and emptying system includes:
at least one ballasting intake through which water is passed from the water displacement system into said ballast system; and
at least one ballasting outlet through which said water displacement system draws water from the ballast system.
Preferably, the rapid filling and emptying system further includes a common orifice and a valve, wherein the ballasting outlet and ballasting inlet are configured to be coupled to the ballast system at the common orifice, and the valve is positionable to close one or both of the ballasting inlet and ballasting outlet.
Preferably, the rapid filling and emptying system is capable of filling the ballast system with sufficient ballast to substantially increase the mass of the craft and thereby lower the position of the craft in water, in order to substantially reduce the portion of the craft visible above water.
Preferably, the craft includes the ballast and rapid filling and emptying systems, and water drawn from the ballast system is used to propel the craft.
Advantageously, preferred embodiments allow a craft to right without assistance.
For ease of understanding, the description and Figures provided below will not show the ballast system and/or rapid filling and emptying system in isolation, but will instead show those systems when housed within a craft. However, the ballast system and/or rapid filling and emptying system may be incorporated into existing vessels and water craft as required. In addition, the mass system shown in the drawings forms part of the ballast system, though the purpose of the ballast system and the purpose of the mass system may be served by separate systems as appropriate.
The water displacement system will be hereinafter described as having a single “propulsion system”. However, the water displacement system may be provided with separate propulsion systems, being a drive propulsion system and a rotate propulsion system, to respectively propel the craft across water and displace water in a manner which causes the craft to rotate about its axis. Furthermore, the description and Figures only show the water propulsion systems to be located at the rear end of the craft, however, it will be understood that water propulsion systems may also be located at positions intermediate the ends, closer to the center of gravity of the craft, for example.
Preferred embodiments of the present invention are hereafter described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
As used herein, to ‘right’ is to return from a capsized or overturned position to an upright position, without the aid of external devices or other vessels. A similar meaning also applies to related words such as “righting” and “rights”.
Like reference numerals will be used herein to refer to similar features depicted in the various drawings.
The craft 10 shown in
The craft 10 further comprises a water displacement system 23 coupled to said body 14 in a suitable manner, including a propulsion system 24, for propelling water 12 through the water displacement system 23, and a water propulsion system 26. The water propulsion system 26 is operable to displace water 12 to propel the craft 10 across water 12, and to displace water 12 to cause the craft 10 to rotate about its axis 22. Though the functions of propelling the craft 10 across water 12 and causing the craft 10 to rotate about its axis 22, may employ separate water propulsion systems 26, in the present case, the water propulsion system 26 is moveable between a drive position and a rotate position, as shown in
The craft 10, as shown in
When the water propulsion systems 26a, 26b move into respective rotate positions, as shown in
To move the water propulsion systems 26a, 26b from a drive position to a rotate position, each water propulsion system 26a, 26b may include a trim nozzle 30 which is pivotable between drive and rotate positions, as shown in
As an alternative to trim nozzles 30, the water propulsion systems 26a, 26b may include diverters 32 (also known as “buckets”), as shown in
The altered diverter 40 includes an hydraulic ram 44 coupled between the side of the diverter 40 and the stern 18 of the craft 10. By coupling the hydraulic ram 44 to the side of the diverter 40, rather than the top of the diverter 40 as shown in
The fixed nature of the hinge 46 ensures that the altered diverter 40 only redirects water from the jet outlet 34 towards the top 42 of the craft 10, and not towards the bottom 38. Therefore, the hinge 46 prevents the craft 10 from being able to rotate in both clockwise and anticlockwise, in order to right. This can be disadvantageous as conditions which may assist in righting rotation may instead serve to compete against that rotation. For example, as shown in
As an alternative to the hinge 46, a second hydraulic ram 52 (shown by the broken line) may be used to position the diverter 40. This can allow the diverter 40 to direct flow towards either the top 42 or bottom 38 of the craft 10, thereby selectively rotating the craft 10 in either a clockwise or anticlockwise direction. In any event, control systems for trim nozzles 30, diverters 32, 40 and hydraulic rams 44, 52 are known and will not be described herein in further detail.
The propulsion system 24 will generally be a water jet system and will thus require water intakes 54 as shown in
Any of the intakes 54, 56 may have, for example, butterfly valves (not shown) mounted at their respective openings so that when a valve is closed (i.e., the respective intake 54, 56 is not in use) the surface of the valve remains flush with the surface of the body 14, thereby minimizing the possibility that the craft 10 will be detected by radar. In circumstances where a capsizing has occurred, or continuous sharp or evasive maneuvering is required, the valves may respond to the change in orientation of the craft 10, by automatically opening and closing to maintain flow through the propulsion system 24. This can be achieved by, for example, comparing accelerometer signals, which indicate the pitch of the craft 10, to the respective positions of the intakes 54, 46, to determine which intakes 54, 56 should be in contact with the water 12. A table listing the intakes which should be open/closed for any particular pitch sensed by the accelerometers, may also be consulted to determine which intakes should be open/closed. Alternatively, a laser sensor (not shown) may be inserted into one or more of the intake pipes 58, as shown in
The intakes 54, 56 may all feed into common intake manifolds 60, or be otherwise connected as appropriate. At these piping joins 62, undesirable flow disturbances can occur due to changes in inner surface features of the pipes 58. To minimize these disturbances, further valves can be used to block one pipe and open another. For example, a rotatable cylinder 64, as shown in
The rotatable cylinder 64 includes two channels 66a, 66b which lie in a plane generally perpendicular to the axis of rotation of the rotatable cylinder 64. The first channel 66a is substantially straight and has the same diameter as the standard intake pipe 58a, which is preferably also the diameter of the auxiliary intake pipe 58b. In the drive position, as shown in
The rotatable cylinder 64 can be driven by any known means, such as a small standard motor, to rotate between drive and rotate positions, and the same principle of auxiliary intakes can be used for air supply to the engine.
As an alternative to the rotatable cylinder 64, hinged, sprung flaps 70 as shown in
The flap 70 is constructed to substantially conform to the surface of the standard intake pipe 58a to which it connects, thereby minimizing flow disturbances during normal use of the propulsion system 24. The flap 70 may also be configured so as to provide efficient flow redirection from the auxiliary intake pipe 58b down the standard intake pipe 58a, though this is less important as the auxiliary intakes 56 should only rarely be used.
In some craft 10, similar intakes 56 will be provided for air. However, in the present case, the auxiliary intakes 56 are used for both water and air. This is achieved by branching the auxiliary intakes 56 into each of the fuel/air mix and water intakes (not shown) of the propulsion system 24, in a manner similar to that shown in
Alternatively, as the event of capsizing should not occur regularly, the craft 10 may not have any auxiliary intakes 56 which supply air to the propulsion system 24. Instead, the craft 10 may be provided with a tank of compressed air (not shown) coupled to the propulsion system 24, which is opened if the craft 10 capsizes. The tank supplies air to be mixed with the fuel in order to run the propulsion system 24. Although the tank may be designed such that it has a specific number of uses, or a specific duration of use at a particular throttle position, it is preferable that the craft 10 be provided with a motor (not shown) that is capable of refilling the tank when the craft 10 is in use. The motor may be separate to the propulsion system 24, but is preferably driven by the propulsion system 24.
In addition, the propulsion system 24 must be supplied with fuel when the craft 10 has capsized. In this case, a standard intake at the bottom of the fuel tank 74 will be insufficient as that intake may be at the highest point of the fuel tank 74 when the craft 10 is in a capsized position. Accordingly, the fuel intake (not shown) from the fuel tank 74 into the propulsion system 24 includes a hose extending into the fuel tank 74, which is provided with a weight at the end. When the craft 10 is operating in either a normal or capsized condition, the weight will draw the hose to the lowest point in the fuel tank 74, thereby allowing fuel to be continuously supplied to the propulsion system 24. The weight may also be substituted for any other appropriate means for providing continuous fuel supply irrespective of tank position.
To ensure the craft 10 is balanced while in motion, it is preferable that its center of gravity be both close to the water 12 and equally distributed across the width of the craft 10—this can be achieved by positioning the fuel tank 74, munitions 76 and other heavy items near the bottom 38 of the craft 10, as shown in
In order to move the center of gravity to an off-center position, the internal volume of the craft 10 includes a ballast system 78, as shown in
The intakes 56 may in some craft contain additional water displacement devices, such as pumps, impellers, propellers or thrusters which can draw water into the main propulsion system should the main propulsions system be unable to draw water from an un-primed pipe. In some embodiments, these displacement devices may take the place of the main water displacement system 24, and be sufficiently strongly powered to direct the water to provide a force about the axis to assist in righting the boat, or rapidly fill the ballasting system.
In some craft, the ballast tanks may additionally be filled, or partially filled by directly opening an orifice that is submerged below the water. The filling, or partial filling of tanks by this method may advantageously, assist in shifting the center of gravity to one side or end of the boat which would more reliably place an intake 54 or 56 in contact with the water to allow for the powered righting system and/or ballast system to be utilized.
The propulsion system 24, as shown in
In addition, the propulsion system 24 includes a ballast inlet 90 in at least one of the ballast tanks 80, to allow rapid evacuation of the ballast system 78. The ballast inlet 90 connects to a ballast inlet pipe 92 which itself is connected to an intake manifold 60, upstream of the propulsion system 24. In the embodiment shown, the ballast inlet pipe 92 and ballast outlet pipe 86 form a common connection pipe 94 which includes a valve 96 for selectively opening and closing each ballast outlet 84 and ballast inlet 90. Advantageously, when water 12 is drawn from the ballast system 78 through the ballast inlet 90, it can be used to propel the craft 10. Furthermore, if the propulsion system includes a ballast inlet 90 in communication with the internal volume of the body 14 of the craft, in the event that the body 14 of the craft 10 is breached (i.e., by collision with a solid body or through penetration from projectiles such as bullets), the ballast inlet 90 may act as a rapid bilge pump to keep the craft 10 afloat and preferably at least partially operational. Alternative inlets 90 and outlets 84 may be provided as appropriate, in accordance with known ballasting systems 78.
The decks of the craft 10 may provide a broad, and generally flat surface in generally coplanar contact with the water 12 when upside-down. As such, the craft 10 would be quite stable, and hence difficult to right in this orientation. The ballasting system 78 is advantageously used to move the boat's 10 central axis away from the plane of the waterline to reduce the amount of torque required to achieve rotation to right the craft 10. By progressively filling the ballast tanks 80a, 80b, 80c from either the rear 18 or the front 16 of the craft 10, or partitioning the ballast tanks 80a, 80b, 80c into generally forward or rear sections one of which would be filled first, the craft 10 comes to have its front 16 or rear 18 end lowered substantially in the water 12, and the other end raised. In doing so, the axis of rotation is brought away from the plane of the water's surface, and the amount of water 12 that must be displaced in order to rotate the craft 10 about its axis to an upright orientation is reduced, and hence reduce the torque required to achieve such a rotation.
To facilitate this, the ballast tanks 80a, 80b, and 80c are filled from the rear 18 of craft 10, by opening a gate or valve (not shown) towards the rear of the tanks 80a, 80b, 80c which is submerged under water 12 when the craft 10 is in an upside-down position. Alternatively, the ballast filling system 78 pumps water into the rear of the tanks 80a, 80b, 80c by positioning the ballast outlet 84 towards the rear of the tanks 80a, 80b, 80c. In some embodiments, both of these methods of filling the tanks 80a, 80b, 80c are enacted in quick succession, or simultaneously.
In another alternative embodiment, the tanks 80a, 80b, 80c are filled from the front 16 of the craft 10 by opening a valve or gate (not shown) submerged when upside-down towards the front 16 of the craft 10, or repositioning the ballast outlet 84 towards the front of the tank.
Advantageously, the ballast tanks 80a, 80b, 80c would be filled in this fashion prior to the water displacement system 23 being engaged to provide a torque about the axis to rotate the craft 10.
Though the body 14 of the craft 10 may be formed from flat panels, the possibility of radar detection, visual sighting or projectile impact (i.e., bullet spray) of the craft 10 can be reduced by reducing the proportion of the craft that visible above surface of the water 12. In this regard, the lower the buoyancy, the greater the proportion of the craft 10 that is submerged and the lower the possibility of radar detection. To lower the buoyancy, the volume of the ballast system 78 may be sufficient such that, when filled with ballast, the mass of the craft 10 is substantially increased thereby lowering the position of the craft 10 in the water 12, in order to substantially reduce the portion of the craft 10 that is visible above the water 12. In emergency situations, such as military exercises, it will be preferable to increase the mass rapidly. Accordingly, in such circumstances, the propulsion system 26 will displace water 12 into the ballast system 78 in order to increase the relative mass of the craft 10 rapidly. Similarly, when it is desired that the craft 10 once again be capable of fast maneuvering, the propulsion system 26 should extract water 12 from the ballast system 78 in preference to water 12 from outside the craft 10.
To ensure low buoyancy, the bottom ballast tank 80a may simply be formed from the volume defined between the body 14 of the craft 10 and the proportion of the volume of the craft 10 which must remain dry, for example the cabin 98 and electrical cabinet 100, as shown in
Although having been hereinbefore described as being advantageous, the body 14 may not be formed entirely of flat panels but may alternatively be partially, or not at all, formed from flat panels.
The axis 22 about which the craft 10 rotates may shift, relative to the craft, whilst it is righting, and may not necessarily be located down the center of the craft 10. However, as water craft 10 will generally be greater in the length dimension than the width dimension (i.e., longer between the ends 16, 18 than between the sides 20a, 20b), the axis 22 will usually run along the length of the craft 10 as shown, as it generally requires less effort to rotate a body about the longer dimension.
The water propulsion systems 26a, 26b may not act in unison but may, instead, be independently operable to cause the craft 10 to rotate about the axis 22. In addition, the water propulsion system 26 may include outlets located at some point intermediate the sides 20a, 20b of the craft 10 (i.e., near the center of gravity of the craft 10), providing more stable rotation.
Although hydraulic rams 44 have been used in, for example, the control of the position of the trim nozzles 30 or diverters 32, 40 of the propulsion system 24, any suitable position controlling mechanism may be employed. The same applies for any of the other features requiring positional control.
Valves, rotatable cylinders 64 and any other suitable flow controlling mechanisms may be used interchangeably in the applications described herein. In addition, the drive mechanisms for valves, rotatable cylinders 64, hinged, sprung flaps, and other features of the embodiments described herein, may be any suitable mechanism. Electromagnetic couplings 72 may be used though their materials can tend to become corroded, or become unreliable due to disturbances from the water 12. Small motors and mechanically rotatable mechanisms are preferred as many such mechanisms are known, are efficient, and may only require a small aperture to be formed in the pipe 58, 58a, 58b, 86, 88, 92 in order to receive the shaft about which a larger component, which remains in the pipe 58, 58a, 58b, 86, 88, 92 (i.e., the disc of a butterfly valve), rotates.
Many combinations, of the features herein described, and modifications to the described embodiments will be apparent to those skilled in the art without departing from the scope of the present invention as hereinbefore described with reference to the accompanying drawings.
Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010900212 | Jan 2010 | AU | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/AU2011/000044 | 1/17/2011 | WO | 00 | 8/27/2012 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2011/088499 | 7/28/2011 | WO | A |
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| 20120318184 A1 | Dec 2012 | US |
