WO2009081090A1

WO2009081090A1 - Led illumination arrangement

Info

Publication number: WO2009081090A1
Application number: PCT/GB2008/003844
Authority: WO
Inventors: Gareth Peter Evans
Original assignee: Lumishore Limited
Priority date: 2007-12-21
Filing date: 2008-11-14
Publication date: 2009-07-02
Also published as: GB0725118D0; GB2455829A; GB0811439D0

Abstract

The invention relates to an underwater illumination apparatus consisting of an LED module (4,6) comprising at least one light emitting diode, that can be mounted directly to the engine (2) of a motorised boat. The LED modules can be mounted by means of a clamp, so that no drilling of the engine or boat hull is required and they can be quickly and easily installed and removed. The LED modules can be single-wavelength, fixed-multiwavelength or multi coloured and changeable.

Description

LED ILLUMINATION ARRANGEMENT

The present invention is directed to an underwater LED illumination apparatus; in particular, but not exclusively to an underwater LED illumination apparatus for use in marine environments .

Underwater lights using halogen and incandescent technologies are well established in the marine industry. The prior art devices are usually mounted on the transom (the back) of the vessel to illuminate the water to view and attract sea life and or create a pleasant ambient lighting effect.

More recently, light emitting diodes (LEDs) have been considered as a candidate light source for underwater illumination purposes, since LED technology has developed to a stage where LED arrangements can produce sufficiently bright light for underwater illumination purposes.

US 2007/0139913 describes an LED-based lighting system for underwater illumination. The arrangement of US 2007/0139913, in common with many prior art arrangements using halogen and incandescent technologies, includes mounting a lighting arrangement in the hull of the vessel. This type of installation has at least the following disadvantages:

1) The vessel has to be in a dry dock situation for installation to begin;

2) If the units fail, the vessel would need to be dry docked again for repair work (In some units a removable bulb can be replaced from inside the vessel. However, sufficient space to allow such a procedure needs to be provided and is rarely available . )

3) The integrity of the hull below the waterline may be compromised due to the requirement to drill into or create holes with substantial diameter through the hull;

4) If the units are damaged (for example struck by an underwater object) or fail due to manufacture defect, they could allow water to flow into the vessel and cause significant damage or even worse, cause the vessel to sink;

5) The units require an experienced and qualified person to fit the unit, ensuring excess damage to the hull does not occur during installation;

6) The units are in a fixed location. The light pattern cannot be adjusted horizontally or vertically to suit the user requirements or to follow the wake of the vessel when turning; 7) For high power LED based units it is critical to cool the devices. This is usually achieved by having a sufficient surface area of the enclosure in contact with the surrounding water. This inherently means that the devices are often very large and cumbersome in size making them unsuitable for smaller vessels where space is at a premium; and 8) If the units are fitted through the hull or transom they may then cause a potential ignition source for trapped flammable vapour.

The present invention- aims to address at least some of the problems identified above. The present invention provides a system for providing underwater illumination suitable for use with a motorised boat, the system comprising a lighting module comprising at least one light emitting diode, and an engine, wherein said lighting module is mounted to said engine.

The present invention also provides a method of illumination, the method comprising mounting a lighting module to an engine of a motorised boat, wherein the lighting module comprises at least one light emitting diode .

Mounting the lighting module to the engine when the engine is attached to the boat provides an easy retrofit arrangement and avoids the necessity of removing the boat from the water.

Until recently LEDs have not been powerful enough to create the sufficient intensity to illuminate the water with any substantial effect. Recent improvements in LED technology mean that they can now be made more powerful and more efficient than their predecessors with the added benefit of overall size reduction and immediate colour change capability.

Halogen trim tab lights are presently available but due to the comparatively large size of the halogen bulb the devices are cumbersome, create large amounts of drag and the halogen technology is prone to premature failure caused by hull vibration and thermal shock. The standard expected lifetime of a halogen bulb is 3000-7000 hours. During the course of the life of the product, the bulb would need to be changed a number of times. The device would have to allow for this service with a form of re- sealable enclosure. This would provide a potential weak point in the device where it would not remain watertight if the seal is broken, dirty or incorrectly fitted. The lifetime of an LED is greater than 50,000 hours; this means, that the LED will not need to be replaced for the expected lifetime of the device. The enclosure can therefore be designed as a one piece watertight housing with no serviceable parts.

If a colour change is required then a colour filter would need to be placed in front of the halogen light source. This is a very inefficient method of producing coloured light since most of the broad spectrum is thrown away. In addition to this the only method of then changing the colour would be to manually replace this filter with another of a different colour.

In one form of the invention, the engine is an outboard engine. In an alternative form of the invention, the engine is an inboard engine and the lighting module is attached to the out leg of said inboard engine. Other \ engine arrangements could also be provided, such as a surface drive or a jet drive.

In some forms of the invention, the lighting module is attached to the cavitation plate of a motor. In other forms of the invention, the lighting module is attached to another suitable mounting point of an outboard engine or out leg of an inboard engine. A variety of different attachment mechanisms could be used, including, but not limited to, clamping, strapping and bolting. The lighting module may be attached to a fin, the fin being suitable for attachment to the cavitation plate of a motor. The fin may be arranged to provide extra lift when a boat is moving through the water. The lighting module may be an integral part of the fin.

In an alternative embodiment of the invention, the lighting module may be an integral part of the engine. The engine may be built including an integral lighting module, or alternatively, the engine may include a receiving section into which the lighting module may be retrofitted. The engine may include an external casing, the lighting module being mounted within the external casing. Making the lighting module an integral part of the engine discourages theft of the lighting module and provides an improved thermal coupling with the engine which acts as a heat sink for the lighting module.

The said at least one light emitting diode may be adapted to provide a controllable coloured output. Further, a control means may be provided for controlling said coloured output. A variety of methods are known in the art for controlling the colour output by an LED array.

The said at least one light emitting diode may be adapted to provide light in the ultra-violet spectrum. The ultra-violet light may be used to break down the growth of organic foul on the lighting module which would otherwise reduce the lighting effect provided by the lighting module. The said at least one light emitting diode may be adapted to provide light with a wavelength in the range from 220nm to 460nm.

The said lighting module may be positioned such that, when the boat is moving in water, the lighting module is cooled by the water. The lighting module may be streamlined in order to reduce the drag caused when using the lighting module. The unit can be provided such that it works at full¹ power when submerged in stationary water; however the thermal resistance between LED and case decreases when subjected to flowing water thus improving the efficiency of the devices and providing a brighter light output.

The system may be arranged such that, in use, the engine acts as a heat sink for said lighting module. If the engine is used as the heat sink, the overall size of the device can be reduced considerably. This results in reduced drag as well as providing a light unit that could work at full power even out of the water

A clamping arrangement, such as a ball clamp, may be provided for mounting the lighting module to the engine. An advantage of using a ball clamp is that the direction of the light output by the lighting module can be readily adjusted.

Alternatively, the lighting module may be bolted directly to the engine using bolts also employed in holding the engine together. Such an arrangement provides a highly secure fixing while not requiring a separate clamp to be used.

A thermal management system may be provided for controlling the temperature of the lighting module. The thermal management system may include a power regulator control system and a temperature sensor for detecting the temperature of the lighting module. For example, a simple thermal management system may be provided that cuts off the power when the temperature of the lighting module exceeds a predetermined temperature. Alternatively, a more sophisticated control system may be provided that adjusts the power provided to the lighting module in dependence of the measured temperature of that module, such that the output light energy is reduced as the measured temperature rises. The control system may include a proportional-integral-derivative (PID) controller. The PID controller may adjust the power provided to the lighting module in such a way that the temperature of the module, when in use, is approximately constant. The PID controller may comprise an algorithm; the algorithm may include differential or integral elements in order to improve the effectiveness of the PID controller.

When a boat is being powered through the water at high speed it may plane, resulting in the lighting module leaving the water, with the resultant loss of cooling of the system. The use of more sophisticated control system, as detailed above, enables the lighting module to continue to emit light when the boat is planing, at a reduced power to prevent overheating of the system. Furthermore, the use of a sophisticated control system improves the performance and temperature control of the lighting module when it is powered while a boat is stationary. Additionally, the use of a sophisticated control system may allow the LED to be overdriven when the boat is moving through the water with the lighting module submerged and the cooling effect of the water has reduced the temperature of the LED to a level where it is safe to do so.

Any control electronics, such as thermal management systems and power regulator control systems used would generate heat. Accordingly, such electronics systems may be housed in the body of the lighting module such that mechanisms for removing heat from the light emitting diodes are also used for removing heat generated by said control systems.

A plurality of lighting modules may be provided in a particular implementation of the invention. By way of example, a plurality of stacked lighting modules may be provided. A control system may be provided for individually controlling selected ones of the plurality of lighting modules. Alternatively or in addition, some or all of the lighting modules may be controlled together to provide similar outputs.

The said lighting module may comprise a sealed enclosure housing said at least one light emitting diode. The enclosure may be adapted to maintain water resistance through the complete life of the lighting module.

The enclosure may act as a thermal path for heat to travel away from said at least one light emitting diode. The enclosure may be used both to carry electrical signals to the LEDs or LED die and to provide a thermal path of the LEDs to the surrounding water or air and/or to the engine.

In some embodiments the said lighting module may comprise a first part and second part, wherein the first part is mounted to the engine and the second part houses the said at least one light emitting diode, the first and second parts being connectable so as to form a sealed unit. Advantageously this means that the lighting module may easily be changed from, for example, one that emits white light, to one that emits, for example, coloured, changeable or ultraviolet light, without the entire module needing to be replaced. This feature also allows the user to install any new type of LED unit that might become available without needing to purchase a whole new module.

A lens may be provided to both modify light output by said at least one light emitting diode and to provide a barrier to surrounding water. The lens may, for example, be a single glass or plastic lens. Alternatively, separate lenses may be provided for each LED.

The lighting module may comprise a die having a plurality of light emitting diodes mounted thereon, wherein the die is mounted on a thermal carrier.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings of which:

Figure 1 is a highly schematic elevation view of a motor incorporating two light modules in accordance with an aspect of the present invention; Figure 2 is a side view of the motor of Figure 1;

Figure 3 is a cross-section of a lighting module in accordance with an aspect of the present invention;

Figure 4 is a side view of a lighting module in accordance with an aspect of the present invention; Figure 5 is a cross-section of an LED array used in an embodiment of the present invention;

Figure 6 is a block diagram demonstrating the control of a lighting system in accordance with an aspect of the present invention; Figure 7 is a block diagram demonstrating the control of a lighting system in accordance with an aspect of the present invention;

Figure 8 shows a first clamping arrangement in accordance with an aspect of the invention;

Figure 9 shows a second clamping arrangement in accordance with an aspect of the invention;

Figure 10 shows an alternative attachment arrangement in accordance with an aspect of the invention;

Figure 11 is a rear view of an alternative attachment arrangement in accordance with an aspect of the invention;

Figure 12 is a side view of the alternative attachment arrangement as shown in Figure 11;

Figure 13 shows the stacking of lighting modules in accordance with an aspect of the invention;

Figure 14 shows an embodiment of the invention in which the lighting modules form part of ^'a fin arrangement; and

Figure 15 shows an alternative embodiment of the invention, where the lighting module is integrated with ^• the engine.

Until recently the main source of light that could provide sufficient levels of illumination for underwater illumination purposes were incandescent, halogen or xenon technologies. An outboard or similar engine generates continuous vibration through normal use. Halogen, incandescent and xenon lighting technologies are very susceptible to premature failure when subjected to even slight vibration or mechanical shock and so are unsuitable for direct attachment to the engine. When the vessel is underway, any illumination unit will be subject to large and constant water pressures. Given that the body of the vessel will need to be designed so that a replacement bulb can be fitted, a potential weak point for water ingress to damage the system is created.

The inventor has realised that if LED light modules are used, the imperative to locate the lighting module away from the motor is removed. This is because LED lighting modules are typically robust and reliable light sources that are tolerant to excessive vibration. This is due, at least in part, to the solid state nature and hermetic encapsulation of LED lighting modules. Furthermore, the LED unit can be designed as a one piece fully integrated enclosure with no serviceable parts or weak points.

Figures 1 and 2 show a motor 2 to which first 4 and second 6 LED modules are attached. As shown in Figure 1, two LED modules are shown, with one being positioned on either side of a cavitation plate 8 of the motor 2.

The LED modules 4 and 6 can be single wavelength, fixed multi-wavelength (e.g. blue and red to create purple) or multi coloured and changeable by using three or more wavelengths at varying intensities.

As shown in Figures 1 and 2, the LED modules 4 and 6 are attached directly to the outboard engine 2. Alternatively, one or more LED modules could be attached to the out leg of an inboard engine.

By attaching one or more LED modules to an engine, the illumination path created by the light need not be fixed. The illumination direction can be altered in the vertical direction by use of the engine trim and follow the horizontal direction of the engine when steered. With the vessel underway this will create a dynamic colour effect through the wake of the vessel.

As shown in Figure 1, a clamping arrangement (discussed further below) is used to attach the LED modules to the motor. This means that no drilling of the hull or engine is necessary. The lighting modules can be attached or , removed as required with no physical adjustment or alteration required to the engine or vessel itself. As such the integrity of the vessel and engine above and below the waterline is not altered in any way.

The LED modules can be installed to the outboard motor or leg in the trim up position with the vessel still in the water. The vessel does not need to be lifted onto dry land for the installation or replacement of the lights. The light can be attached and detached as desired, either on land or in the water.

The location of the LED modules on the outboard motor or the out leg of an inboard engine is such that the device is positioned directly into the water flow path created by the movement of the vessel or underwater current. The water flow over the case of the device is directly proportional to the heat transfer. A faster flow of water will encourage greater heat transfer out of the LED resulting in a more efficient system and brighter device.

Directly attaching the housing of the device to the outboard motor or out leg of an inboard motor also improves the thermal management system by using the engine itself as a large water-cooled heat sink. As a result, the LED modules can be made smaller and more efficient and since cooling does not rely solely on the direct contact of the LED module with the surrounding air or water they can be used at full power even out of the water.

Figure 3 shows an LED module, indicated generally by the reference numeral 30, in accordance with an aspect of the present invention. The module 30 comprises a main body 32, an LED array 34 and a clamp 38. The LED array 34 is associated with a lens 36. Figure 5 shows a close-up of the LED array 34 and the lens 36. As shown, the array 34 comprises three individual LEDs, labelled 35a, 35b and 35c respectively.

In one form of the invention, the lens 36 is a single optically clear lens made from glass or a plastics material. The lens is held in place by either a gasket or a ring arrangement or is glued in place such that a watertight seal is made. The purpose of the lens 36 is to provide a watertight seal with an air gap between the lens and the LEDs 35a, 35b and 35c and also to alter the beam profile created by the bare LEDs. Various beam angles can be achieved by selecting different focal length lenses and by adjusting the position of the lens from the array.

The lens 36 could also be abraded or a film of light- diffuser material could be added to the system to create a diffused lighting effect.

In an alternative embodiment, a single plastic lens could be placed over each of the individual LEDs 35a, 35b and 35c. The front lens would then not be required and could be replaced with a standard glass or toughened plastic plate .

The LEDs 35a, 35b and 35c may be identical, with each outputting light having the same wavelength.

Alternatively, the LEDs may output light having different wavelengths in order to allow the overall light output of the array 34 to be varied. LEDS with a phosphor coating could also be used to create white light. The LEDs may be adapted to provide ultra-violet light. The ultra-violet light may be used to break down the growth of organic foul on the LED module 30, for example on the lens 36 of the LED module 30. The LEDs may be adapted to provide light with a wavelength in the range 220nm to 460 nm.

In one form of the invention, the LEDs are surface mounted LEDs that are reflow soldered onto a thermally conductive carrier. This arrangement enables the devices to be arranged in close proximity to one another to simulate a point source for improved optical coupling. All necessary electrical connections to each LED would be made through copper tracks embedded onto, but electrically isolated from, the carrier.

In an alternative form of the invention, a die of LEDs is mounted directly onto a thermally conductive carrier. The carrier could be a metal core printed circuit board, a standard printed circuit board or a ceramic base. Without the external packaging the die can be placed closer together thus minimising the size of the complete device and improving optical coupling. When using more than one wavelength there will also be an improvement in colour mixing. The complete array of the LED die is encapsulated using an optically clear index matching gel. The gel serves three purposes. 1) To improve coupling efficiency of the light from the LED die.

2) To provide a water tight seal and protect the die from water ingress, debris and dust.

3) To provide support to the die and wire bonds making the device more resilient to mechanical shock and vibration.

Should the front lens water seal fail, the encapsulate provides an additional water tight barrier ensuring that the device will continue to work.

The LED array and thermal carrier is mounted to the external enclosure 32 of the device 30. The external enclosure 32 is made of a material that has sufficient thermal conductivity to allow the removal, of the heat generated by the LEDS to pass through to the surrounding air or water. A thermally conductive material such as a paste or epoxy is provided between the carrier and the enclosure 32 to improve the conductivity.

The enclosure 32 is preferably made of machined or cast metal or a metal alloy, but could also be made out of thermally conductive plastic or ceramic. The enclosure would preferably be made out of one single piece, but could also be made from multiple pieces of the same material or a combination of materials. The enclosure 32 is shaped to encourage water to pass over it, but is streamlined so that any additional drag caused by the light module is kept to a minimum.

A variant to the arrangement described above uses a thermally conductive ceramic carrier with a metallization layer for the contacts that is also shaped to form the outer enclosure to the device. The LEDS, either as discrete packaged devices or as the bare LED and wire bonds could be mounted directly to the ceramic. This approach has at least the following benefits:

• Fewer components are used, leading to more efficient manufacture. No metal outer enclosure is required. No metal core LED carrier is required. The devices are attached directly to the one-piece ceramic.

• Higher thermal conductivity to the surrounding environment is provided. The devices run more efficiently therefore fewer devices are required to achieve the same light output with less current draw from the battery.

• As a result of the higher thermal conductivity, the same number of devices can be operated more efficiently, resulting in longer lifetimes. • There are no corrosion issues, since the ceramic is completely resilient to attack from the elements.

• No galvanic corrosion is caused to vessel or engine due to the use of dissimilar metal materials.

The body of the device 32 could be made integral to the device enclosure or as a separate part or even part of the drive leg itself, e.g. designed within the cavitation plate or an aftermarket hydrofoil wing. The body could be made from machined or cast metal or metal alloy as well as plastic, rubber or ceramic.

The body is designed to support the front enclosure and clamping mechanism. It may have one of a variety of different shapes but should be streamlined to minimise the drag created in the water.

The body could also provide additional thermal management to the array by increasing the exposed surface area to the air or water or due to its contact with the engine itself allow the heat to transfer into the leg itself.

The body can be used to house any external electronics that are not included on the array itself.

In one embodiment of the invention, shown in Figure 4, the main body of the lighting module 32 comprises a first part 32a and a second part 32b. The first part 32a attaches to the engine, while the second part 32b contains the at least one light emitting diode 35. The first part 32a and the second part 32b are sealably connectable, for example by means of a screw thread 33 and an 0-ring 37, such that when connected they form a water-tight enclosure. When the module is lifted out of the water, for example, by raising the engine, the second part 32b may be disconnected from the first part 32a and replaced with an alternative second part. The alternative second part may include a light emitting diode of a different colour or intensity to the second part 32b.

Figure 6 is a block diagram of an electronic thermal management system, indicated generally by the reference numeral 50, in accordance with an aspect of the present invention.

The arrangement 50 comprises a power supply 52 and a dashboard switch 54 coupled to power regulating electronics 58 of an LED module 56. The LED module includes LED array 59.

The power regulating electronics 58 monitors the temperature of the array substrate and/or the external casing of the device and is programmed to do one of two things :

1) If a predetermined maximum temperature of the device is reached, power to the array is disconnected. The device will remain in the "off" condition until the temperature has cooled to a threshold value at which point power will be reconnected.

2) As the array or casing heats up, power to the array is decreased to the point where a safe equilibrium between temperature and power is reached. In this case the array will always be in the "on" state and an over temperature condition should not occur. The power regulating electronics 58 may include a PID controller adapted to keep the temperature of the array substrate substantially constant during use. The PID controller may allow the array to be overdriven with additional current when the lighting module is submerged and the boat is travelling through the water. The cooling effect of the moving water may reduce the temperature of the array to a level at which the array can be safely overdriven, thus increasing the output of the array. The power regulating electronics 58 are either mounted onto the LED array carrier or assembled on their own carrier but housed within the enclosure of the unit and in close proximity to the array 59. If separate from the array 59, the power regulating electronics 58 are encapsulated with a silicon potting compound to protect them from exposure to water.

A DC-DC converter and regulator may be provided to switch between 12-volt and 24-volt input automatically as part of the supply 52. Electronics are provided in the main housing of the device or external to the device in their own splash proof enclosure. The devices can be operated by a dash mountable switch 54 or via a radio or infrared remote switch thus providing wireless free switch installation

The lighting module 56 may also be controlled by a series of control inputs via the dash switch 54 or remote to perform various colour changing, flashing sequences or intensity variations.

The following list highlights some of the potential control input modes and resulting effect.

The system of the present invention enables two or more light modules to be controlled either simultaneously or as an individual device. For example, where more than one wavelength is used this will allow a colour wheel effect, where the colour change from one device can merge into the next unit. Figure 7 shows an arrangement in which LED modules 67, 68 and 69 are controlled from a control unit 66. Power is supplied from a power supply unit 62 and operator control is provided using a dash control 64. As described above, a clamp is used to attach the light module to a mounting position, such as the cavitation plate of an outboard engine. The clamp may be an integral part of the body of the device or may be provided as an interchangeable piece to allow the device to be attached in a variety of positions by altering the type of clamp used. _^ The clamps should provide sufficient clamping pressure to hold the light modules in place even at high speeds where they will be subject to excessive force from the water flow and wash from the propeller.

Figure 8 shows a compression clamp in which a top plate of the clamp is fixed to the body of the light module. A separate moveable clamp plate is attached to the first clamp plate by using one or more screws. With the cavitation plate placed in between the plates the screw is tightened allowing the plates to pivot upon their axis and clamp onto the cavitation plate.

The light modules can be attached at the side of the clamp as shown in Figure 8. Alternatively, the light modules could be attached either above or below the clamp.

An alternative clamp design is a clamp including the integration of an adjustable ball' joint clamp, as shown in Figure 9. This allows the unit to be made adjustable by using a ball joint between the clamp and the device. This would mean if the units were attached to a fixed location such as the vessels transom or trim tab their position could later be altered as desired. One or more screws can be used to simultaneously clamp the unit to the plate as well as applying the necessary pressure on the ball joint to hold the unit in position. For fishing application and sea life observation this would be particularly useful for directing the beam of light downwards to the seabed.

In an alternative form of the invention, the main body of the light module could be designed to incorporate the clamp itself. The design could allow the units to be mounted on the side of a plate as discussed above or be designed to allow the device to be mounted at the front of the engine.

To discourage theft or to fix the unit to irregularly shaped mounting plates or mounting plates that have a thickness exceeding the limit of the clamp, a semipermanent method of attaching the device would be to screw or bolt the device directly to the cavitation plate. Such an arrangement is shown in Figure 10.

Figures 11 and 12 show an alternative embodiment of the invention, where the body of the lighting module 115 is adapted so that it may be fixed directly to the engine using bolts 113 that also hold the engine 92 together.

To allow the user to increase the total illumination the device body is designed so that one or more devices can be stacked together utilizing the. same single clamp. An arrangement including two LED modules 102 and 104 stacked together is shown in Figure 13.

Figure 14 shows another alternative embodiment of the invention, where at least one LED module 112 forms part of a fin 114 that is mounted to the cavitation plate of the engine 116. The fin 114 may be retrofitted to an engine and be arranged such that it provides extra lift to a boat being driven through water. The LED module 112 may be removably mounted to the fin 114 or an integral part of the fin 114.

Figure 15 shows a further alternative embodiment of the invention, whereby the LED module 122 is an integral part of the engine 124. This further discourages theft of the LED module and provides an improved thermal coupling with the engine 124 which acts as a heat sink for the LED module 122. The LED module 122 may be included in the engine when it is built, or retrofitted to a receiving section present on the engine 124. The engine 124 may include an external engine casing into which the LED module is mounted.

To illuminate the back of the boat and or the water immediately in front of or underneath the vessel the units could incorporate an LED array on both the front and back of the device. The devices pointing fbrward could be of lower intensity to create an ambient effect or of greater intensity to illuminate the water below and in front of the vessel.

Claims

CLAIMS :

1. A system for providing underwater illumination suitable for use with a motorised boat, the system comprising: a lighting module comprising at least one light emitting diode; and an engine, wherein said lighting module is mounted to said engine.

2. A system as claimed in claim 1, wherein the engine is an outboard motor.

3. A system as claimed in claim 1, wherein the engine is an inboard engine and the lighting module is attached to the out leg of said inboard engine.

4. A system as claimed in any one of claims 1 to 3, wherein said at least one light emitting diode is adapted to provide a controllable coloured output.

5. A system as claimed in any preceding claim, wherein said at least one light emitting diode is adapted to provide an ultra-violet output.

6. A system as claimed in claim 4, further comprising a control means for controlling said coloured output.

7. A system as claimed in any preceding claim, wherein said lighting module is positioned such that, when the boat is moving in water, the lighting module is cooled by the water.

8. A system as claimed in any preceding claim, wherein, in use, said engine acts as a heat sink for said lighting module .

9. A system as claimed in any preceding claim, wherein said lighting module is mounted to said engine using a clamp.

10. A system as claimed in claim 9, wherein said clamp is a ball clamp.

11. A system as claimed in any of claims 1-8, wherein the lighting module is mounted directly to the engine by means of the bolts also employed in holding said engine together.

12. A system as claimed in any of claims 1 to 8, wherein the said lighting module is an integral part of the engine .

13. A system as claimed in claim 12, wherein the engine comprises an external engine cover into which the lighting module is received.

14. A system as claimed in any of claims 1 to 10, wherein the said lighting module is mounted to a fin.

15. A system as claimed in any preceding claim, further comprising a thermal management system for controlling the temperature of the lighting module.

16. A system as claimed in claim 15, wherein said thermal management system comprises a power regulator control system.

17. A system as claimed in claim 16, wherein the power regulator control system includes a PID controller.

18. A system as claimed in any preceding claim, wherein said system comprising a plurality of lighting modules.

19. A system as claimed in any preceding claim, wherein said lighting module comprises a sealed enclosure housing said at least one light emitting diode.

20. A system as claimed in claim 19, wherein said enclosure acts as a thermal path for heat to travel away from said at least one light emitting diode.

21. A system as claimed in any preceding claim, wherein the lighting module comprises a first and second part, wherein the first part is mounted to the engine and the second part houses the at least one light emitting diode, the first part and second part being connectable so as to form a sealed enclosure.

22. A system as claimed in any preceding claim, further comprising a lens used to both modify light output by said at least one light emitting diode and to provide a barrier to surrounding water.

23. A system as claimed in any preceding claim, wherein said lighting module comprises a die having a plurality of light emitting diodes mounted thereon, wherein the die is mounted on a thermal carrier.

24. A system as claimed in claim 23, wherein the thermal carrier is a ceramic carrier with a metallization layer.

25. A system as claimed in claim 24, wherein the ceramic carrier is also shaped to form an outer enclosure to the device .

26. A method of illumination, the method comprising mounting a lighting module to an engine of a motorised boat, wherein the lighting module comprises at least one light emitting diode.

27. A method as claimed in claim 26, wherein said lighting module is adapted to provide a controllable coloured output, the method further comprising the step of controlling the coloured output of said lighting module.

28. A method as claimed in claim 26 or claim 27, further comprising the step of positioning the lighting module such that, when the boat is moving in water, the lighting module is cooled by the water.

29. A method as claimed in any one of claims 26 to 28, further comprising the step of using said engine as a heat sink for said lighting module.

30. A method as claimed in any one of claims 26 to 29, further comprising a thermal management system for controlling the temperature of the lighting module.

31. A method as claimed in claim 29, wherein the thermal management system includes a PID controller.

32. A kit of parts for providing underwater illumination comprising a lighting module including at least one light emitting diode, and a fin, wherein the lighting module is arranged to be mounted to the fin and the fin is arranged to be mounted to an engine of a motorised boat.

33. A fin for mounting on to the engine of a motorised boat, the fin comprising an integrated lighting module including at least one light emitting diode for providing underwater illumination.