WO1998038516A1

WO1998038516A1 - A speed monitoring device

Info

Publication number: WO1998038516A1
Application number: PCT/IE1998/000015
Authority: WO
Inventors: Owen Paul Patrick Laverty
Original assignee: Owen Paul Patrick Laverty
Priority date: 1997-02-28
Filing date: 1998-02-27
Publication date: 1998-09-03
Also published as: AU6308398A

Abstract

A speed monitoring device (1) for monitoring the speed of a boat (2) through water, the monitoring device (1) comprising a body member (5) for mounting on the hull (6) of the boat (2), a monitoring means (17) mounted in the body member (5) for interacting with the water and being responsive to the speed of the boat (2) relative to the water, a mounting means (10, 53, 55) for mounting the body member (5) on the hull (6) adjacent an opening (8) in the hull for accommodating the centreboard (12), the mounting means (10, 53, 55) being engageable with the body member (5) and being adapted for passing through the opening (8) in the hull (6), and being anchorable to the boat (2) for securing the body member (5) to the hull (6), and a communicating means (24) for relaying signals from the monitoring means (17) to a control means (25) located within the boat (2) for providing a signal suitable for feeding to a visual display means (46) for displaying the speed of the boat (2) relative to the water.

Description

"A speed monitoring device"

The present invention relates to a speed monitoring device, and in particular, to a speed monitoring device for a boat, typically a sailing boat, of the type comprising a daggerboard, a centreboard, or the like, hereinafter collectively referred to as a centreboard.

In sailing dinghies, in order to monitor the speed of the dinghy through the water, it is necessary to attach a speed monitoring device to the hull of the boat. Such speed monitoring devices, typically comprise a housing and an impeller which is rotated by the action of the water against the impeller as the boat passes through the water.

The use of speed monitoring devices or indeed any non-standard fittings can be forbidden during dinghy racing. Accordingly, it is desirable that such devices should be releasably and reversibly secured to the hull .

Known methods for securing such monitoring devices to the hull of a boat require the use of screws, rivets, glue or adhesive tape, or alternatively, insertion of the monitoring device in a dedicated hole in the boat. With the exception of adhesive tape, the aforementioned known methods tend to be permanent securing methods or methods which require dedicated fittings. Indeed, even in boats and other crafts where it is desired to permanently secure a monitoring device to the hull, known methods are also unsatisfactory. For example, screws and rivets require drill holes into or through the hull which can compromises the hull's buoyancy and integrity and are prone to theft.

Adhesive tape is the only reasonably acceptable known method for releasable attachment. However, the use of adhesive tape is clearly also unsatisfactory. More particularly, where glue and/or adhesive tape is employed, it is essential that the surface be properly prepared for adhesion or bonding by thoroughly cleaning and drying the surface. Clearly, thorough cleaning and drying of a boat hull can be a difficult operation particularly where rapid fitting of a device is necessary.

Moreover, even following removal of devices mounted on a hull employing adhesive tape, glue or the like adhesive residues can remain which can impede movement of the boat through water and encourage adhesion of other matter to the hull.

German Patent Specification No. 3,219,393 describes a speed monitoring device in which a transmitter for detecting speed is attached by a bayonet socket to a fastening plate fixed on the hull of a boat. Alternatively, a paddle wheel transducer can be fixed to the hull and cabling to the display unit passed through a hole formed in the hull of a boat.

Bayonet sockets are usually permanently fitted to a boat and can result in unacceptable drag when the speed measuring device is not in use.

PCT Patent Specification No. PCT CH/85/02010 describes a speed monitoring device in which the device is fixed with dedicated fittings to a hull. The speed of the boat is detected and transmitted to an instrument without cabling. However, the distance between the speed detector and the instrument is limited as the signal cannot be transmitted long distances.

German Patent Specification No. 2842658 describes a speed monitoring device in which a speed detecting impeller is towed from a boat and a revolution rate transducer returns a signal to an output indicator. However, the towing of a speed detecting impeller from a boat can clearly result in unacceptable drag on the boat and can also result in the impeller snagging on objects in use. An object of the invention is to provide a monitoring device which can be easily secured to the hull of a boat.

A further object of the invention is to provide a monitoring device which can be secured to the hull of a boat either permanently or temporarily without requiring modification to the hull or any additional fittings.

It is a further object of the invention to provide a speed monitoring device that, when temporarily fitted, may be easily removed from the hull.

It is a still further object of the invention to provide a speed monitoring device that minimises drag on a boat in use.

According to the invention there is provided a speed monitoring device for monitoring the speed of a boat through water, the monitoring device comprising a body member for mounting on the hull of the boat, a monitoring means mounted in the body member for interacting with the water and being responsive to the speed of the boat relative to the water, a mounting means for mounting the body member on the hull adjacent an opening in the hull for accommodating a centreboard, the mounting means being engageable with the body member and being adapted for passing through the opening in the hull, and being anchorable to the boat for securing the body member to the hull, and a communicating means for relaying signals from the monitoring means to a control means located within the boat for providing a signal suitable for feeding to a visual display means for displaying the speed of the boat relative to the water.

Preferably, the mounting means comprises an elongate mounting strap extendible through an opening defined by a centreboard casing. More preferably, the mounting means comprises an insertion plate mounted on the body member for mounting the device adjacent the centreboard opening. Advantageously, the insertion plate comprises a conduit for conveying the communicating means through the hull of the boat. Preferably, the insertion plate comprises strap gripping means. More preferably, the strap gripping means comprises strap sandwiching means.

Suitably, the elongate mounting strap comprises a conduit for conveying the communicating means through the centreboard casing of the boat. Advantageously, the conduit comprises a hollow core in the mounting strap.

Preferably, the mounting strap terminates in an engagement means for attaching the mounting strap to a tensioning means for tensioning the mounting means. Suitably, the tensioning means comprises resilient means.

Advantageously, the resilient means comprises a resilient rope anchorable to the boat.

Preferably, the body member is adapted for mounting on the hull centre line, adjacent the centreboard opening. More preferably, the body member is shaped for facilitating centering of the body member relative to the hull centre line. Most preferably, the body member comprises a locating means for locating the body member centrally relative to the centreboard opening. Advantageously, the locating means comprises a pair of locating tongues for extending upwardly adjacent the centreboard opening. Preferably, the locating tongues engage opposite peripheral side edges of the centreboard opening. More preferably, the locating tongues engage a recess adjacent the centreboard opening. Most preferably, the locating tongues engage between rubbing strips on opposite sides of the centreboard.

Advantageously, the locating means comprises a relieved portion on the body member for engaging the centreboard. Preferably, the locating means comprises a locating recess for engaging the hull centre line or rubbing strip.

Suitably, the monitoring means comprises an impeller rotatably mounted in the body member.

Advantageously, the impeller comprises a rotatable magnet, the magnet being communicable with a proximity switch being located in the body member such that the proximity switch is responsive to the magnet as the magnet passes the proximity switch on rotation of the impeller for generating an electrical signal for transmission through the communicating means to the control means.

Suitably, the proximity switch comprises guide means to guide the communicating means between the proximity switch and the visual display means. Advantageously, the guide means comprises orienting means to orient the proximity switch towards the visual display means.

Preferably, the guide means comprises engaging means for engaging the mounting means. More preferably, the engaging means comprises a cylinder mounting insertable in the mounting means.

In a preferred embodiment of the invention the body member comprises two halves which are separably mounted together.

Suitably, the halves are separable along a longitudinally extending axis disposable parallel to the centre line of the boat.

Advantageously, the impeller is rotatable on a shaft extending between the two halves of the body member.

Preferably, the impeller is removable from the shaft on separation of the halves of the body member.

Suitably, the mounting means is engageable with a shaft extending from one of the halves of the body member, and is removable from the shaft on separation of the halves of the body member.

Preferably, the shaft comprises a connecting screw between the two halves.

The invention also extends to a method for monitoring the speed of a boat through water comprising mounting a speed monitoring device on the hull of the boat adjacent a centreboard opening and passing a mounting means engageable with the speed monitoring device through the opening. Preferably the mounting means is mounted between the speed monitoring device and an anchoring means through the centreboard opening.

A preferred method comprises anchoring the mounting means to the boat with a tensioning rope.

Suitably, the mounting means comprises a mounting strap.

Preferably, communicating means for communicating between the speed monitoring device and a visual display means are passed through the centreboard casing.

Preferably, the communicating means are housed in the mounting strap.

The invention also provides a speed monitoring device for monitoring the speed of a boat through the water, the monitoring device comprising a body member for mounting on the hull of the boat, a monitoring means mounted in the body member for interacting with the water and being responsive to the speed of the boat relative to the water, a mounting means for mounting the body member on the hull adjacent an opening in the hull for accommodating a centreboard, the mounting means being engageable with the body member and being adapted for passing through the opening in the hull, and being anchorable within the hull for securing the body member to the hull, and a communicating means for relaying signals from the monitoring means to a control circuit located within the boat for providing a signal suitable for feeding to a visual display means for displaying the speed of the boat relative to the water.

The invention will be more clearly understood from the following description of embodiments thereof which is given by way of example only with reference to the accompanying drawings, in which:

Fig. 1 is a front perspective view of a speed monitoring device according to the invention mounted on the underside of a hull of a boat;

Fig. 2 is a rear perspective view of the speed monitoring device of Fig. 1;

Fig. 3 is a side elevational view of a portion of the speed monitoring device of Fig. 1;

Fig. 4 is a perspective view of the portion of the speed monitoring device of Fig. 3;

Fig. 5 is another perspective view of the portion of Fig. 3 of the speed monitoring device of Fig. 1;

Fig. 6 is another perspective view of the portion of Fig. 3 of the speed monitoring device of Fig. 1;

Fig. 7 is a side elevational view of a portion of a boat illustrating the speed monitoring device of Fig. 1 mounted on the underside of the hull of a boat provided with a pivotable centreboard;

Fig. 8 is a partly sectional side elevation of a portion of a boat provided with a daggerboard illustrating the speed monitoring device of Fig. 1 mounted on the underside of the hull;

Fig. 9 is an enlarged perspective and partial cross- sectional view of the device of Figs. 1 to 6 mounted at the centreboard opening on the hull of a boat;

Fig. 10 is an underneath plan view of the speed monitoring device of Figs. 1 to 6 mounted on the hull of a boat;

Fig. 11 is an underneath perspective view of a second embodiment of a speed monitoring device in a partially disassembled form in which the speed monitoring device is provided with an insertion plate for inserting through the seal on the hull of a boat;

Fig. 12 is a side elevation of a first half of the device of Fig. 11;

Fig. 13 is an exploded perspective view of the half of the speed monitoring device of Figs. 11 and 12;

Fig. 14 is a perspective from below of the speed monitoring device of Figs. 11 to 13 mounted on the hull of a boat;

Fig. 15 is a side elevation of a first half of a third embodiment of a speed monitoring device in accordance with the invention similar to the embodiment described in Figs. 11 to 14, and

Fig. 16 is a partially cut away side elevation of a controller for use with the speed monitoring devices of figures 1 to 15 showing an inductance coupling mechanism.

Figs. 1 to 10 show a first embodiment of a speed monitoring device in accordance with the invention. The speed monitoring device is indicated by the reference numeral 1 and is adapted for monitoring the speed of a boat 2 through water.

Generally, the speed monitoring device 1 of the invention comprises a body member 5 of plastics material which is particularly suitable for mounting on the underside of a hull 6 of the boat 2, and in particular, for mounting centrally on a centre line of the hull 6 of the boat 2 adjacent a centreboard opening 8 of the boat 2.

A mounting means for mounting the speed monitoring device 1 on the boat 2 comprises an elongate hollow mounting strap 10. The mounting strap 10 is engaged in the body member 5 as will be described more fully below and in use passes through a casing 11 of a centreboard 12 of the boat 2. The centreboard opening 8 is provided with two elongate overlapping sealing strips 51, 52 which extend the length of the centreboard opening 8 to prevent excessive ingress of water through the centreboard opening 8. The centreboard 12 is passed between the overlapping strips 51, 52 during lowering and raising of the centreboard 12 through the opening 8. The mounting strap 10 is also passed between the sealing strips 51, 52 in use and serves as a conduit for electrical communication between the speed monitoring device 1 and a controller as shall be explained more fully below. The mounting strap 10 terminates in an eye member 14 which is engageable with a tensioning rope 15 located at the top of the casing 11. The tensioning rope 15 is in turn anchored or attached at its free end 44 to an anchoring means such as a mast 39. The tensioning rope 15 is resilient and serves to exert a pulling force or tension on the strap 10 to hold the speed monitoring device 1 against the hull 6.

A monitoring means for interacting with the water, and which is responsive to the speed of the boat relative to the water comprises an impeller 17 of plastics material. The impeller 17 is rotatably mounted on a shaft 18 as will be described below in a recess 20 in the body member 5. The impeller 17 is made up of four blades 21 disposed at right angles to each other which extend outwards from a central opening 45 for mounting on the shaft 18. Two bar magnets (not shown) are moulded into opposite blades 21 of the impeller 17 at 22. A proximity or reed switch 23 is located in the body member 5 which is responsive to the magnets in the two blades 21. As the respective magnets pass the reed switch 23 a signal is induced in a communicating means, namely, in a pair of wires 24 of an electrical circuit which is connected to a control means, namely, a controller 25.

The controller 25 is provided with suitable electrical circuitry, incorporating a printed circuit board (PCB) (not shown) for counting the number of times the reed switch 23 opens and closes as the magnets in the impeller blades 21 pass the reed switch 23. The controller in turn computes the speed of the impeller 17 from the number of openings and closings of the reed switch 23 during a predetermined period of time. The controller 25 comprises a display 46 for displaying the speed of the boat thereon as shall be explained more fully below in relation to Figure 16.

The body member 5 is formed in first and second halves 26, 27 respectively of injection moulded plastics material. The half 26 carries the shaft 18 on which the impeller 17 is mounted through the impeller central opening 45 and is rotatable. The shaft 18 is of sufficient length to extend into a corresponding recess (not shown) in the half 27. Screws 28 and 30 extend through the first and second halves 26, 27 respectively for securing the two halves 26, 27 of the body member 5 together. The recess 20 within which the impeller 17 is located is formed in and defined by and between the first and second halves 26, 27 respectively. The halves 26 and 27 are spaced apart or relieved at 32 to define a gap 47 for accommodating the mounting strap 10 and also for receiving or accommodating the edge of a centreboard 12 in use. The mounting strap 10 is hemmed at 35 for mounting the strap 10 on the shaft 48 of the screw 30 so that when the two halves 26 and 27 are secured together, the mounting strap 10 is secured and retained on the screw 30 between the two halves 26, 27.

The wires 24 extend from the reed switch 23, and in turn, pass into a conduit or hollow bore 36 defined by the mounting strap 10 via an inlet opening 37. Accordingly, the wires 24 are passed through the casing 11 in the mounting strap 10 thereby protecting the wires 24 and also partially combining the mounting and communicating means between the speed monitoring device 1 and the controller 25 to minimise visible and potentially disruptive cabling/wiring and the like.

Moreover, the wires 24 are protected from abrasion and wear in use within the mounting strap 10.

An outlet opening 38 at the other end of the mounting strap 10 remote from the inlet opening 37 accommodates the wires 24 from the bore 36. The wires 24 extend from the outlet bore 38 and are in turn passed along the mast 39 and inserted in the controller 25 as shall be explained more fully below.

The body member 5 is shaped for facilitating laminar flow of water over the body member 5. More particularly, the body member 5 is shaped to optimise the fluid dynamics of the speed monitoring device so that, firstly, the speed monitoring device 1 is urged against the hull 5 by the flow of water over the body member 5, secondly, the body member 5 minimises drag and, thirdly, flow of water past the recess 20 which houses the impeller 17 is optimised. Drag is minimised due to the location of the speed monitoring device 1 at the centreboard opening 8 on the hull 6 of the boat adjacent the centreboard 12. Accordingly, the device 1 does not result in a virgin source of drag on the hull 6 but rather any drag produced by the device 1 is simply in addition to the drag resulting from the centreboard 12.

The speed monitoring device 1 is shaped to be easily located on the hull 6 adjacent the centreboard opening 8. More preferably, the front of the body member 5 is provided with a longitudinally extending recess 40 for accommodating a central rubbing strip 41 or centre line on the hull of the boat 2. The presence of a central rubbing strip 41 or line is dependent on the hull type. However, the body member 5 is shaped to centre the body member 5 on the rubbing strip 41 or centre line as required.

A pair of locating means, namely, locating tongues 43 extend upwards from the respective halves 26 and 27 of the body member 5 either side of the gap 48 to the rear of the body member 5 for engaging in the centreboard opening 8 as illustrated in Figs. 8 to 10, or in recesses 7 defined either side of and adjacent to the centreboard opening 8 as illustrated in Figs. 1 and 2. More particularly, as shown in Figs. 1 and 2, the hull 6 of a boat 2 can be typically provided with elongate recesses 7 defined either side of the centreboard opening 8. The recesses 7 are defined by two lateral rubbing strips 74 located on the hull 6 either side of the centreboard opening 8, and are exploited by the locating tongues 43 of the speed monitoring device 1 to locate the speed monitoring device 1 adjacent the centreboard opening 8. More particularly, the locating tongues 43 are held within the recesses 7 by the rubbing strips 74.

Moreover, the gap 48 disposed between the two halves 26, 27 of the body member 5, the fluid dynamic shape of the body member 5 and the locating tongues 43 in combination impart the body member 5 with a degree of resilience or flexibility that enables the locating tongues 43 on each body member half 26, 27 to flex such that upon tensioning of the mounting strap 10 the locating tongues 43 flex either side of the recesses 7 to maximise contact of the monitoring device 1 with the hull 6 to optimise engagement of the speed monitoring device 1 of the invention with the hull 6.

Moreover, where the body member 5 is manufactured from a plastics material, the flexibility and hence the engagability of the speed monitoring device 1 of the invention with the hull 6 is further optimised.

Similarly, as shown in Figs. 8 to 10, the locating tongue can be tensioned or urged inwards by the centreboard opening 8 such that the flexibility of the locating tongues 43 of the two halves 26, 27 is adjusted such that the locating tongues 43 are biased laterally outwards against the internal edges of the centreboard opening 8.

The flexing nature of the locating tongues 43 can be controlled by adjusting the screws 28, 30 to vary the pressure exerted on the two halves 26, 27 of the body member 5. Accordingly, as the screws 28, 30 are tightened, the two halves 26, 27 are urged more closely together at the gap 48 such that grip at the recesses 7 is increased. Similarly, where the screws 28, 30 are loosened between the two halves 26, 27 of the body member 5, the gap 47 is increased between the two halves 26, 27 such that the locating tongues 43 move apart and the grip between the locating tongues 43 and the internal edge of the centreboard opening 8 may be increased.

Moreover, the centreboard 12 can rest in the gap 47 and urge the two halves apart in use.

The locating tongues 43, the gap 47, and the use of two separable halves 26, 27 in the construction of the body member 5 therefore facilitates the centring and locating of the body member 5 on the hull 6 adjacent a centreboard opening 8.

Moreover, as indicated above, the body member 5 is shaped and contoured for urging the front of the body member into tight engagement with the hull 6, thereby avoiding entanglement of the device with weeds, debris and/or other matter. The leading portion of the body member 5 is hydrodynamically shaped for urging the leading portion of the body member into tight engagement with the hull 6 to further ensure that entanglement with weeds, debris and other matter is avoided.

Figs. 11 to 14 show a second embodiment of a speed monitoring device 1 in accordance with the invention. The speed monitoring device 1 is broadly similar to the device described in Figs. 1 to 10 and accordingly like numerals indicate like parts. The speed monitoring device 1 is made up of a body member 5 having a first half 26 and a second half 27 as previously described. The speed monitoring device 1 is also provided with an impeller 17 disposed between the two halves 26, 27 for determining the speed of movement of a dinghy or other vessel. However, the embodiment of Figs. 11 to 14 is especially adapted for mounting on the hull 6 of a boat having no recesses, rubbing strips or other contours thereon with which the locating tongues 43 can engage to position the speed monitoring device 1 on the hull 6. Nevertheless, such hulls are generally provided with two elongate overlapping sealing strips 51, 52 as previously described adjacent the centreboard casing 11.

The second embodiment of the speed monitoring device 1 in accordance with the invention is provided with an insertion plate 53 which extends upwards between the first and second halves 26, 27 of the body member 5 in the gap 47. The insertion plate 53 is typically manufactured from a folded over plate metal material and can be urged between the sealing strips 51, 52 to locate the speed monitoring device 1 on the hull 6 of a boat.

A foam or similar protective padding means 33 is wrapped about the free end of insertion plate 53 to prevent movement of the insertion plate between the sealing strips 51, 52 and to prevent the insertion plate 53 from passing through the sealing strips 51, 52 and to protect the sealing strips 51, 52 from the metal of the insertion plate 53.

As with the mounting strip 10 of Figs. 1 to 10, the insertion plate 53 is shaped to define an internal insertion plate channel 54 through which the wires 24 pass through the hull 6 into the centreboard casing 11 as previously described. As shown in the drawings, the wires 24 are conveyed through the centreboard casing in a mounting strap 55, similar to the mounting strap 10 of Figs. 1 to 10, secured between the insertion plate 53 and an anchoring rope 15 as previously described. Typically, the mounting strap 55 is gripped between opposing faces of the folded over insertion plate 53 as described more fully below.

As shown in the drawings, the insertion plate 53 is made up of the channel 54 as previously described and a gripping plate portion 56 made up of a first face 57 and a second face 58 between which the mounting strap 55 may be gripped so that the mounting strap 55 may be tensioned upon connection to the anchoring rope 15 as previously described. The insertion plate 53 is provided with a through hole 59 through which a transverse insertion plate mounting screw 60 may be passed between the first and second halves 26, 27 to support the insertion plate 53 between the first and second halves 26, 27.

Moreover, the mounting screw 60 is passed through the mounting strap 55, disposed between the first and second faces 57, 58 of the insertion plate 53 to grip the strap 55 in the insertion plate 53.

The mounting screw 60 is passed through the first and second halves 26, 27 of the body member 5 through screw openings 61, 62 in the first and second halves 26, 27 respectively of the body member 5.

The through hole 59 is defined in a head portion 63 of the insertion plate 53, while the head portion 63 is shaped to define a rear notch 64 disposed adjacent the channel 54 and a front notch 65. The insertion plate 53 is mounted between the first and second halves 26, 27 on the mounting screw 60 as previously described while a reed switch 23 located in a reed switch guide holder 66 is mounted in the front notch 65 parallel to the axis defined by the mounting screw 60.

However, in the present embodiment, the reed switch holder 66 comprises a cylindrical mounting 67 having an elongate open channel 68 defined therein parallel to the longitudinal axis of the cylindrical mounting 67. The channel 68 has an open mouth 69 into which the wires 24 of the reed switch 23 are inserted. The mouth 69 is oriented to direct the wires 24 towards the channel 54 in the insertion plate 53 to ensure that the wires 24 are correctly oriented or presented with respect to the reed switch holder 66 to minimise stress and strain on the wires 24 in use and to prevent accidental removal of the wires 24 from the reed switch holder 66.

The cylindrical mounting 67 is contoured on its outer surface to define a flat face 70 to enhance the fit in the front notch 65 of the insertion plate 53.

Two spacer cylinders 71, 72 are disposed either side of the rear notch 64. The spacer cylinder 71, 72 are provided with an internal contiguous bore 73 through which the rear screw 30 of the speed monitoring device 1 is passed. The spacer cylinders 71, 72 serve to control the distance between the first and second halves 26, 27 of the body member 5 by varying the length of the spacers by tightening and loosening the screw 30 so that the dimensions of the gap 48 can be varied in accordance with the distance it is required to maintain between the locating tongues 43.

Spacer cylinders 71, 72 of varying lengths can be employed to further determine the dimensions of the gap 48 as required.

Fig. 15 shows one half 26 of a third embodiment of a speed monitoring device 1 in accordance with the invention. The speed monitoring device 1 of Fig. 15 is broadly similar to the speed monitoring device of Figs. 11 to 14 and like numerals indicate like parts. However, the present embodiment is specifically adapted for use where no sealings strips 51, 52 are present. The insertion plate 53 is omitted and the reed switch holder 66 is adapted to be directly mounted on the mounting screw 60 and the rear screw 30 can be omitted. More particularly, in the present embodiment the cylindrical mounting 67 is provided with a laterally extending mounting head 75. The mounting head 75 defines a through hole 76 adapted to be located over the mounting screw 60. A mounting strap 10 broadly similar to the mounting straps previously described is mounted over the cylindrical mounting 67 at the hem 35 so that the wires 24 emerging from the channel 68 of the cylindrical mounting 67 at the mouth 69 are secured within the mounting strap bore as previously described. However, in the present embodiment, the orientation of the channel 68 within the cylindrical mounting 67 ensures that the wires 24 are correctly presented or oriented with respect to the mounting strap 10 so that a direct path is followed from the reed switch 66 to the mounting strap 10 to avoid unnecessary stress and strain on the wires 24 in use.

Fig. 16 shows a partially cut away side elevation of the controller 25 for use with the speed monitoring device 1 of Figures 1 to 15. Externally, the controller 25 is made up of a housing 3 having a rear panel 4 and a front panel 9 attached to the rear panel 4. The front panel 9 is provided with a visual display 46 for displaying the speed recorded by the speed monitoring device 1 and solar cells 13 for powering the controller 25. Internally, the housing 3 contains an inductance coupling mechanism 16 for use in connecting the wires 24 to the controller 25. More particularly, the wires 24 are connected to a printed circuit board (not shown) within the housing 3 by a ferrite core 19 mounted at the free ends of the wires 24. The ferrite core 19 is removably inserted into a socket 29 surrounded by an outer inductance coil 31 to receive the signal conveyed through the wires 24 and the ferrite core 19. In turn, the coil 31 communicates with the printed circuit board of the controller 25 as will be appreciated by those skilled in the art.

In use, to mount the speed monitoring device 1 on the boat 2, the body member 5 is located on the hull 6 by either positioning the locating tongues 43 in the recesses 7 or between the edges of the centreboard openings adjacent the centreboard opening 8.

In the embodiment of the speed monitoring device described in Figs. 1 to 10 and Fig. 15 the mounting strap 10 is passed through the centreboard opening 8 and the centreboard casing 11 and the eye member 14 is secured to the tensioning rope 15. For example, in the case of the hull of Figs. 1, 2 and 7 which comprise a pivotally mounted centreboard, the locating tongues 43 engage a recess formed adjacent spaced apart rubbing strips 49 which are located on either side of the centreboard opening 8. In the case of the hull of Figs. 8 to 10, which comprises a vertically displaceable centreboard or daggerboard, the locating tongues 43 engage inside the centreboard casing. Thus, the centreboard of the hull of Figs. 8 to 10 passes through the gap 47 in the body member 5 between the locating tongues 43. The engagement recess 40 engages the rubbing strip 41 or centre line of the hull 6, and the combination of the recess 40, locating tongues 43 and relieved portion 32, prevent sideward movement and twisting of the monitoring device 1 on the hull 6, thereby retaining the monitoring device 1 closely parallel to the centre line of the hull.

Similarly, the tensioned mounting straps 10, 55 urge the speed monitoring device 1 against the hull 6 preventing movement of the speed monitoring device 1 on the hull.

In the embodiment shown in Figs. 11 to 14, the insertion plate 53 is inserted through the sealing strips 51, 52 as previously described.

The controller 25 is mounted at an appropriate location in the boat, typically, on the mast 39. As the boat progresses through the water, the action of the water on the impeller 17 rotates the impeller 17, which in turn causes the reed switch 23 to open and close as the magnets pass the reed switch 23 to generate a series of signals in the wires 24 which are relayed to the controller 25 through the mounting strap 10, 55. The rate of generation of the signals in the wires 24 is proportional to the rotational speed of the impeller 17, which in turn is proportional to the speed of the boat through the water. The controller 25 computes the speed of the boat from the signals in the wires 24, and in turn displays the speed on the visual display 46.

It should be noted that the monitoring device 1 may be mounted on the hull 6 by offering the monitoring device 1 up to the hull 6 and pulling the mounting strap 10 through the centreboard casing 11. Alternatively, the monitoring device 1 may be passed downwardly through the centreboard casing 11 while retaining the mounting strap 10 within the hull 6.

While the impeller housing has been described as being of a plastics material, the housing may be of any other suitable material. A resilient material is preferred for enhancing abutment against the hull 6 and for reducing the risk of damage to the housing 5 in use.

It will be appreciated that while the monitoring means has been described as comprising an impeller 17, any other suitable monitoring means may be provided. While, it will be appreciated that the shape and construction of the body member may be varied without departing from the scope of the invention.

In an alternative embodiment of the invention, the magnets in the impeller 17 may be remotely sensed, for example, by a remote sensing means located internally in the hull thereby obviating the need for the wires 24.

In an alternative embodiment of the invention, the impeller may be of a magnetic material.

While the monitoring device has been illustrated mounted on different hull constructions, the monitoring device 1 according to the invention may be mounted on many different types of hulls, and in particular, is adapted for mounting on virtually all types of sailing dinghy hulls.

In an alternative embodiment of the invention, a single locating tongue 43 may be provided, and the locating tongue 43 may be shaped to correspond to the leading portion of the centreboard opening 8 for engaging in the centreboard opening 8. In such cases, the single locating tongue 43 would be located between the centreboard casing 11 and the centreboard 12, at the forward end of the centreboard opening 8.

While the monitoring device 1 has been illustrated as being attached to the hull 6 adjacent the centreboard casing, the monitoring device 1 may be attached to any portion of the hull 6. Indeed, the monitoring device 1 may also be attached to any submerged foil .

It will also be appreciated that any other means for monitoring the impeller 17 may be provided besides a reed switch 23, and where a reed switch 23 is provided, the reed switch 23 may be provided by a Hall switch, or other suitable switches.

Additionally, it will be appreciated that the relieved portion 32 of the monitoring device may be of any desired shape besides that illustrated, and in certain cases, may be of shape similar to the leading edge of the centreboard for accommodating the centreboard. The advantages of the invention are many. In particular, the monitoring device 1 according to the invention can be readily easily fitted to a hull, either permanently or temporarily without compromising the integrity of the hull e.g. without the need for drilling or cutting holes or the like in the hull 6, or without the need for using any conventional fixing means, for example, screws, rivets or adhesives. The speed monitoring device of the invention can simply be offered up to the hull 6 and the mounting strap 10 passed through the centreboard opening 8 and attached to a tensioning rope 15 which in turn is attached to a suitable anchoring point on the boat 2. Alternatively, the mounting strap 10 can be attached directly to a suitable anchoring point in the hull. The device of the invention can be readily easily mounted to the hull 6 without the need for cleaning or drying the hull 6. However, it will be appreciated that the area of the hull 6 to which the device is to be mounted should be at least clean prior to mounting the device 1 thereto.

The mounting device of the invention can be readily easily removed from the hull 6 as required, and upon removal leaves no residues, fittings or traces of it having been mounted on the hull. A further advantage of the invention is that should the monitoring device hit an obstruction, the device 1 is pushed towards the rear of the hull 6, since the mounting strap 10 attached to a tensioning rope 15 is stretchable, thereby minimising any potential for damage to the impeller 17. Additionally, the hollow strap 10 of the mounting means provides a conduit and protective casing for the wires 24 communicating between the reed switch 23 and the controller 25. Buoyancy is not compromised by drilled holes or the like. In addition since the monitoring device 1 is removable it is safe from theft. Additionally, the hull 6 can continue to comply with the legal requirements provided for in class racing rules by simply removing the speed monitoring device 1.

Claims

CLAIMS:

1. A speed monitoring device (1) for monitoring the speed of a boat (2) through water, the monitoring device (1) comprising a body member (5) for mounting on the hull (6) of the boat (2), a monitoring means (17) mounted in the body member (5) for interacting with the water and being responsive to the speed of the boat (2) relative to the water, a mounting means (10,53,55) for mounting the body member (5) on the hull (6) adjacent an opening (8) in the hull for accommodating a centreboard (12), the mounting means (10,53,55) being engageable with the body member (5) and being adapted for passing through the opening (8) in the hull (6), and being anchorable to the boat (2) for securing the body member (5) to the hull (6), and a communicating means (24) for relaying signals from the monitoring means (17) to a control means (25) located within the boat (2) for providing a signal suitable for feeding to a visual display means (46) for displaying the speed of the boat (2) relative to the water.

2. A device as claimed in Claim 1 characterised in that the mounting means (10,53,55) comprises an elongate mounting strap (10,53,55) extendible through an opening (8) defined by a centreboard casing (1).

3. A device as claimed in Claim 2 characterised in that the mounting means (10,53,55) comprises an insertion plate (53) mounted on the body member (5) for mounting the device (1) adjacent the centreboard opening (8).

4. A device as claimed in Claim 3 characterised in that the insertion plate (53) comprises a conduit (54) for conveying the communicating means (24) through the hull (6) of the boat (2).

5. A device as claimed in Claim 4 characterised in that the insertion plate (53) comprises strap gripping means (57,58,59,60).

6. A device as claimed in Claim 5 characterised in that the strap gripping means (57,58,59,60) comprises strap sandwiching means (57,58).

7. A device as claimed in any of Claims 1 to 6 characterised in that the elongate mounting strap (10,55) comprises a conduit (36) for conveying the communicating means (24) through the centreboard casing (11) of the boat (2).

8. A device as claimed in Claim 7 characterised in that the conduit (36) comprises a hollow bore (36) in the mounting strap (10,55).

9. A device as claimed in any of Claims 2 to Claim 8 characterised in that the mounting strap (10,55) terminates in an engagement means (14,35) for attaching the mounting strap (10,55) to a tensioning means (15) for tensioning the mounting means (10,55).

10. A device as claimed in Claim 9 characterised in that the tensioning means (15) comprises resilient means (15).

11. A device as claimed in Claim 10 characterised in that the resilient means (15) comprises a resilient rope (15) anchorable to the boat (2).

12. A device as claimed in any of Claims 1 to 11 characterised in that the body member (5) is adapted for mounting on the hull centre line, adjacent the centreboard opening (8).

13. A device as claimed in any of Claims 1 to 12 characterised in that the body member (5) is shaped for facilitating centering of the body member (5) relative to the hull centre line.

14. A device as claimed in any of Claims 1 to 13 characterised in that the body member (5) comprises a locating means (32,40,43) for locating the body member (5) centrally relative to the centreboard opening (8).

15. A device as claimed in claim 14 characterised in that the locating means (32,40,43) comprises a pair of locating tongues (43) for extending upwardly adjacent the centreboard opening (8).

16. A device as claimed in Claim 15 characterised in that the locating tongues (43) engage opposite peripheral side edges of the centreboard opening (8).

17. A device as claimed in Claim 15 the locating tongues (43) engage a recess (7) adjacent the centreboard opening (8).

18. A device as claimed in Claim 17 characterised in that the locating tongues (43) engage between rubbing strips (74) on opposite sides of the centreboard (12).

19. A device as claimed in any of Claims 14 to 18 characterised in that the locating means (32,40,43) comprises a relieved portion (32) on the body member (5) for engaging the centreboard (12).

20. A device as claimed in Claim 19 characterised in that the locating means (32,40,43) comprises a locating recess (40) for engaging the hull centre line or rubbing strip (41).

21. A device as claimed in any of Claims 1 to 20 characterised in that the monitoring means (17) comprises an impeller (17) rotatably mounted in the body member (15).

22. A device as claimed in Claim 21 characterised in that the impeller (17) comprises a rotatable magnet, the magnet being communicable with a proximity switch (23) located in the body member (5) such that the proximity switch (23) is responsive to the magnet as the magnet passes the proximity switch (23) on rotation of the impeller (17) for generating an electrical signal for transmission through the communicating means (24) to the control means (25) .

23. A device as claimed in Claim 22 characterised in that the proximity switch (23) comprises guide means (66) to guide the communicating means (24) between the proximity switch (23) and the visual display means (46).

24. A device as claimed in Claim 23 characterised in that the guide means (66) comprises orienting means (67,68,69) to orient the proximity switch (23) towards the visual display means (46).

25. A device as claimed in Claim 24 characterised in that the guide means (67,68,69) comprises engaging means (73) for engaging the mounting means (10,53,55).

26. A device as claimed in Claim 25 characterised in that the engaging means (73) comprises a cylinder mounting (67) insertable in the mounting means (53).

27. A device as claimed in any of Claims 1 to 26 characterised in that the body member (5) comprises two separably mounted halves (26,27).

28. A device as claimed in Claim 27 characterised in that the halves (26,27) are separable along a longitudinally extending axis disposable parallel to the centre line of the boat (2).

29. A device as claimed in Claim 27 or Claim 28 characterised in that the speed monitoring means (17) is rotatable on a shaft (18) extending between the two halves (26,27) of the body member (5).

30. A device as claimed in Claim 29 characterised in that the speed monitoring means (17) is removable from the shaft (18) on separation of the halves (26,27) of the body member (5).

31. A device as claimed in Claim 27 characterised in that the mounting means (10,53,55) is engageable with a shaft means (30,60) extendable from one of the halves (26,27) of the body member (5), and is removable from the shaft means (30,60) on separation of the halves (26,27) of the body member (5).

32. A device as claimed in Claim 31 characterised in that the shaft means (30,60) comprises a connecting screw (30,60) between the two halves (26,27).

33. A method for monitoring the speed of a boat (2) through water comprising mounting a speed monitoring device (1) on the hull (6) of the boat (2) adjacent a centreboard opening (8) and passing a mounting means (10,53,55) engageable with the speed monitoring device (1) through the opening (8).

34. A method as claimed in Claim 33 comprising mounting the mounting means (10,53,55) between the speed monitoring device (1) and anchoring means (15) through the centreboard opening (8).

35. A method as claimed in Claim 34 characterised in that the anchoring means (15) comprises a tensioning rope (15).

36. A method as claimed in any of Claims 33 to 35 characterised in that the mounting means (10,53,55) comprises a mounting strap (10,55).

37. A method as claimed in any of Claims 33 to 36 characterised in that communicating means (24) for communicating between the speed monitoring device (1) and a visual display means (46) are passed through the centreboard casing (8).

38. A method as claimed in Claim 37 characterised in that the communicating means (24) are housed in the mounting strap (10,55).