WO2010146360A2

WO2010146360A2 - Improvements relating to submersible apparatus

Info

Publication number: WO2010146360A2
Application number: PCT/GB2010/001184
Authority: WO
Inventors: Kenneth George Storey; Keith Richardson; Harry Lincoln
Original assignee: Active Offshore Solutions Limited
Priority date: 2009-06-19
Filing date: 2010-06-18
Publication date: 2010-12-23
Also published as: WO2010146360A3; GB0910603D0

Abstract

The invention relates to a submersible apparatus (1) locatable at a surface to be cleaned (3), said surface being located in a body of water, the apparatus comprising, a fluid delivery line (8) in fluid communication with a fluid outlet port, the fluid outlet port (25) comprising at least one nozzle (5) configured to induce cavitation in the body of water when a pressurised fluid is passed therethrough, and a platform adapted to locate the at least one nozzle at a pre- determined angle and a pre- determined distance from the surface to be cleaned. The invention further relates to a submersible vehicle comprising: attachment means operable to locate the submersible vehicle at an underwater surface; at least a first equipment attachment port configured to receive a first tool, and at least a first tool operable to inspect an underwater surface and being connectable to the first equipment attachment port, the submersible vehicle further comprising a second equipment attachment port configured to receive a second tool, and a second tool operable to perform an operation on an underwater surface and being connectable to the second equipment attachment port. The invention further relates to a method of cleaning and/or inspecting an underwater surface and of undertaking operations relating to the underwater surface following the inspection.

Description

IMPROVEMENTS RELATING TO SUBMERSIBLE APPARATUS

The present invention relates to a submersible apparatus and method for inspecting and/or maintaining an underwater surface in situ. In particular, but not exclusively, the invention relates to a submersible vehicle capable of inspecting and/or maintaining an underwater surface and, more specifically, to a remotely operated vehicle operable to inspect an underwater surface and to perform a number of underwater tasks in situ. The invention further relates to a method of inspecting an underwater surface and of undertaking in situ operations relating to the underwater surface following the inspection.

Currently sea- and/or water-going vessels require regular inspections to ensure the vessels are operating within safety guidelines and rules. Current standards applicable to such vessels require a so-called intermediate inspection every 2.5 years, and then at a 5 year period the vessel would be required to go into dry dock for a full inspection. The full inspection guidelines require the hull of a vessel to be cleaned and inspected for damage; in extreme cases the hull may need to be re-coated with anti-fouling paint. The anti-fouling coating on a vessel facilitates efficient fuel consumption by improving and maintaining the hydrodynamic efficiency of a vessel in a body of water, which fuel consumption efficiency in turn helps to reduce the carbon footprint associated with the vessel and also reduces the fuel costs to the owners of the vessel by reducing the fuel consumption per nautical mile travelled.

Inspection of vessel hulls and sub-sea structures are currently carried out in the water, at pre-determined points on the structure using single point probes that measure, for instance, thickness and cathodic protection. The area to be tested is cleaned either by divers using high pressure water, brushes or scrapers or the like, or possibly by a free flying ROV using the same implements as the diver but controlled via a mechanical manipulator arm Once the area is clean there is generally a visual inspection to identify any anomalies such as cracks Then the appropriate probe is used to carry out the desired measurements

An intermediate inspection may be earned out on a vessel either in a body of water in which the vessel is operating, i e in situ, or otherwise in a dry dock location A submersible vehicle, in the form of a remotely operated vehicle (ROV), for example, will be launched into the body of water proximate the vessel A ROV pilot will free-fly the ROV to a specified location on the hull of the vessel in an underwater position The ROV will, typically, be equipped with camera and/or scanning equipment which are operable to record video images and/or scan data associated with the underwater surface of the vessel The video images and/or scan data are then recorded and reviewed to ascertain areas of the underwater surface which have become fouled with marine life, or the like, or which are demonstrating reduced structural integrity due to wear and tear, for example A dιver(s) is then employed to locate areas of the underwater surface requiring cleaning, for example, as identified by the ROV-captured video images and/or scanning data The dιver(s) then enters the body of water and locates the area in question before manually carrying out the necessary cleaning work/maintenance on the underwater surface A drawback of this operating scenario is the requirement for dιver(s) to operator in underwater conditions which may be difficult and dangerous Furthermore, it is necessary to employ a team including an ROV pilot and, typically, three or more divers to undertake the necessary operations Once the dιver(s) has completed the cleaning/maintenance required, the ROV is piloted once more to re-inspect the structure in order to ensure that the work has been carried out to the necessary standards This leads to a costly and time-consuming in situ intermediate inspection A full inspection, on the other hand, requires the vessel to be taken completely out of operation for a period of time. In the case of an FPSO (Floating Production and Storage Offshore) vessel, for example, there are large costs associated with the shut down of operations and, subsequently, the movement of the vessel from an offshore, in situ, location to the dry dock required for the inspection and maintenance. Currently, this shut down and movement operation is a requirement at least once in every 5 years of operation.

In order to clean an entire hull or structure, the vessel needs to be taken out of the water, into a dry dock for example, where it is typically blasted using high pressure water that strips off protective coatings. Any damage to the protective coating is then made good in the dry dock.

Free flying ROVs can clean using scrapers, brushes and high pressure water etc. All of these mechanical cleaning tools cause damage to the protective coatings of the structures being cleaned. Known technology has been impractical to completely clean a relatively large hull/structure whilst it is in the water.

As would be appreciated by the skilled artisan, in order to move a vessel from its operating location in a body of water to an inspection and/or maintenance location, considerable costs are associated with a vessel being out of operation. Further still, in order to bring a vessel into dry dock, pilots, pilot vessels and/or tugs are often required to manoeuvre the vessel in question into the dry dock location. By way of example, bringing a vessel into a river-based dry dock location will require a pilot to board the vessel and to manoeuvre the vessel into the river location, alternatively, a pilot vessel may be required to perform the operation. The costs of hiring a pilot and/or a pilot vessel with knowledge of the river and dry dock location are considerable and must, currently be factored into the costs associated with bringing a vessel in for inspection and/or maintenance.

It is an aim of the present invention to reduce the frequency at which vessels are required to go into dry dock and/or to increase the time periods between intermediate and full inspections whilst maintaining the operating and fuel efficiencies provided by a clean vessel hull with a tested and acceptable integrity.

It is a further aim of the present invention is to provide an in situ method of inspecting and maintaining an underwater surface so as to reduce the costs associated with a vessel out of operation and/or the costs associated with moving a vessel into a dry dock location.

It is a yet further aim of the present invention to provide an apparatus and method for inspecting and maintaining an underwater surface of a vessel in situ whilst maintaining the integrity of the anti-fouling coating on the vessel.

According to a first aspect, the present invention provides a submersible apparatus locatable at a surface to be cleaned, said surface being located in a body of water, the apparatus comprising, a fluid delivery line in fluid communication with a fluid outlet port, the fluid outlet port comprising at least one nozzle configured to induce cavitation in the body of water when a pressurised fluid is passed therethrough, and a platform adapted to locate the at least one nozzle at a pre-determined angle and a predetermined distance from the surface to be cleaned.

Cavitation is the formation and collapse of vapour-filled cavities or bubbles and is the result of flow-induced pressure reductions in a fluid. A cavitation-inducing nozzle will accelerate the flow and decrease the pressure below the vapour pressure of water. This, in turn, creates cavitation bubbles with are entrained in the flow. As the stream of bubbles nears the underwater surface to be cleaned, the pressure gradients increase and the bubbles begin to deform and collapse creating localised high stress.

In embodiments, the at least one nozzle comprises a fluid inlet, a fluid outlet and a fluid flow channel therebetween.

It will be understood that the nozzle fluid inlet is in fluid communication with the fluid delivery line.

In certain embodiments, the fluid delivery line may be in fluid communication with a fluid containment tank or, alternatively, a fluid supply source. More specifically, the fluid supply source may be the body of water.

The at least one nozzle may be a fan-type nozzle. In this way, fluid emanating from the fan-type nozzle is projected over a wide area of the underwater surface to be cleaned.

Alternatively, the at least one nozzle may be a single opening, straight delivery nozzle whereby the stream of fluid emanating from the nozzle is directed straight at the underwater surface to be cleaned. In this way a relatively small area of the underwater surface may be targeted and more precise cleaning is facilitated.

In particularly preferred embodiments, the submersible apparatus comprises a plurality of nozzles. The plurality of nozzles may each be located at a pre-determined angle and/or a pre-determined distance from the surface to be cleaned.

In various embodiments, each one of the plurality of nozzles is in fixed orientation with respect to each of the other of the plurality of nozzles. In this way, an array of nozzles, configured to induce cavitation in the body of water when pressurised fluid is passed therethrough, may be located at the surface to be cleaned. Thus, a broad path of the surface may be cleaned in use of the submersible apparatus.

In embodiments comprising a plurality of nozzles, the nozzle fluid outlets are preferably in horizontal alignment with one another. In this way, a single fluid delivery line may be in fluid communication with all of the fluid outlets. Thus, a wide area of the underwater surface may be cleaned.

Alternatively, the array formed by the plurality of nozzles may comprise a number of discrete nozzle fluid outlets each being individually in fluid communication with a fluid delivery line. In this way, more powerful cleaning may be provided at each nozzle fluid outlet. Furthermore, each nozzle fluid outlet may then be independently controllable in terms of fluid delivery rate and pressure.

In various embodiments, the submersible apparatus is moveable with respect to the surface to be cleaned during the cleaning operation. Thus, by moving the submersible apparatus along the surface to be cleaned during the cleaning operation, a large surface area may be cleaned easily.

More specifically, in use, the submersible apparatus is moveable with respect to the surface to be cleaned whilst maintaining the at least one nozzle at the pre-determined angle and the pre-determined distance from the surface to be cleaned.

In preferred embodiments, the pre-determined angle and/or the pre- determined distance are initially adjustable with respect to the surface to be cleaned. In various embodiments, once determined, the predetermined angle (α) and/or the pre-determined distance (d) are fixed for the duration of the cleaning operation. In this way, maximum cleaning efficiency may be selected and maintained during the cleaning operation.

The at least one nozzle is preferably locatable relative to the underwater surface to be cleaned, such that the pre-determined angle (α) between the underwater surface and the longitudinal axis of the at least one nozzle is in the range of 20 to 45 degrees.

Further, in such embodiments, the nozzle is locatable relative to the underwater surface such that a pre-determined distance (d) between the fluid outlet of the nozzle and the underwater surface is between 35mm and 80mm.

More specifically the pre-determined distance d is between 50mm and 76mm.

The pre-determined distance d is measured parallel to the longitudinal axis of the nozzle from the centre of the fluid outlet opening in the nozzle end.

If the pre-determined distance d is less than 35mm, the cleaning capability of the cleaning tool is reduced. In preferred embodiments, the submersible apparatus is engageable against the surface to be cleaned.

More specifically, the submersible apparatus is engageable against the surface to be cleaned and thereafter is moveable with respect to the surface to be cleaned whilst remaining engaged against the surface to be cleaned. Thus, the submersible apparatus is able to crawl along the surface to be cleaned and to clean a path along the surface during operation thereof.

In preferred embodiments, the platform is a submersible vehicle or a part thereof. More specifically, the platform may be a submersible remotely operated vehicle (ROV) or a part thereof.

In embodiments, the at least one nozzle is fixed in position relative to the platform.

It is preferred, when the platform is a submersible vehicle or a part thereof, the distance between the nozzle fluid outlet and the centre point of the submersible vehicle or part thereof is fixed and constant.

In various embodiments, the platform is a rigid member.

More specifically, the platform may be a strut on a submersible vehicle. Even more specifically, the platform may be a strut on a remotely operated submersible vehicle (ROV). Thus, by providing a rigid member upon which the at least one nozzle is mounted, the pre-determined angle and pre-determined distance of the nozzle from the surface to be cleaned, once selected by the operator, may be maintained throughout the cleaning operation. In this way, maximum cleaning efficiency is maintained whilst preventing damage to the surface to be cleaned.

In preferred embodiments, the at least one nozzle is mountable on the platform.

More specifically, the at least one nozzle may be directly mountable on the platform.

Alternatively, the at least one nozzle may be indirectly mountable on the platform. More specifically, the at least one nozzle may be mounted on a bracket with the bracket being mountable on the platform.

The at least one nozzle may be directly coupled to the bracket.

More specifically, the bracket may comprise one or more U-shaped brackets. When the bracket comprises more than one U-shaped brackets, the bracket comprises two opposing U-shaped clamp members which, when joined together, form an O-shaped clamp. In this way, the at least one nozzle may be clamped between the U-shaped brackets and thereby held in position.

Alternatively, the bracket may comprise a single U-shaped bracket and one or more retaining means. The at least one nozzle may be positioned in the U-shaped bracket and held in place by the retaining means. The retaining means may be one or more clamps, attachable to opposing sides of the U-shaped bracket.

In use of the bracket, the at least one nozzle is held in a fixed, pre- determined position relative to the underwater surface. In this way, when the at least one nozzle is a cavitational inducing tool, the pre-determined distance d and the pre-determined angle (α) of the nozzle fluid outlet relative to the surface to be cleaned is maintained and constant, thus, maximising the cleaning efficiency of the tool.

Alternatively or, in addition, the submersible apparatus may further comprise a manifold.

The manifold may comprise a single fluid inlet port in fluid communication with the fluid delivery line. Alternatively, the manifold may comprise a plurality of fluid inlet ports each in fluid communication with a fluid delivery line.

The manifold may comprise the one or more fluid outlet ports. In embodiments, the or each manifold fluid outlet port is releasably coupleable with a nozzle. The releasable coupling may be a screw thread arrangement, for example.

One or more of the manifold fluid outlet ports may receive a blank stopper to prevent fluid flow therethrough. In the way, the surface area to be cleaned can be defined by the operator.

The manifold may receive the fluid delivery line at an input port thereof. In various embodiments, the manifold comprises the fluid outlet port. Thus, the manifold preferably provides a fluid communication path between the fluid delivery line and the fluid outlet port.

The manifold may be attached to the platform. Alternatively, the manifold may be attachable to the platform. More specifically, the manifold may be attached to a bracket which is in turn attached to the platform.

In addition or as an alternative to the manifold, the submersible apparatus may comprise a bracket remote therefrom. In embodiments comprising a manifold and a bracket remote therefrom, the or each fluid outlet port and nozzle has a conduit providing a fluid flow path therebetween. The nozzle(s) may be mountable on the bracket which is, in turn, mountable on the platform. The manifold may also be mountable on the platform.

Preferably the conduit is a flexible hose.

In alternative arrangements, the fluid delivery line is coupled directly to the least one nozzle. In such arrangements, the at least one nozzle is preferably mounted in a bracket to hold same in position.

In preferred embodiments, the at least one nozzle is removably beatable in the fluid outlet port. More specifically, the at least one nozzle may be located into the fluid outlet port by a screw thread arrangement.

It will be understood that the submersible apparatus provides non-contact cleaning of an underwater surface. By inducing cavitation at the fluid outlet of the nozzle upon passing pressurised fluid therethrough, the cavitation provides a cleaning action at the surface without damaging the surface itself. Thus, high pressure fluid delivered to the submersible apparatus may be used to clean a surface of marine debris without mechanical contact and without damaging any surface coatings present. It will be understood that cavitation in a body of water is created by a relationship between the flow rate and the pressure of a fluid.

In preferred embodiments, the pressurised fluid is a liquid. More specifically, the pressurised fluid is water.

In preferred embodiments, the pressurised liquid is delivered at the nozzle fluid outlet at a pressure of between 1000 and 4000psi. More specifically, the pressure is in the range 1600 to 2000psi.

In preferred embodiments, the submersible apparatus may further comprise an inspection tool.

More specifically, the inspection tool may be operable to provide continuous measurements of a parameter associated with the underwater surface.

The inspection tool may be a 3D image generation device.

More specifically, the 3D image generation device may comprise a video camera.

Alternatively, or in addition, the inspection tool may comprise an acoustic resonance testing device operable to inspect the condition of the underwater surface. In particular, the acoustic resonance testing device is operable to produce acoustic resonance which, in use, is used to detect areas of corrosion on the underwater surface and/or areas of marine growth and debris build-up. The acoustic resonance testing device may be further or alternatively operable to detect thickness of specified areas of an underwater surface to determine if it has been worn or degraded. The acoustic resonance testing device is preferably operable to scan the underwater surface and to provide a 3D image of the scanned surface. In this way, irregularities in the underwater surface are detectable.

Alternatively, or in addition, the inspection tool may be operable to inspect the underwater surface and to provide one or more of: ultrasonic thickness measurements and/or resonance thickness measurements and/or cathodic protection thickness measurements allowing accurate thickness measurements to be made at locations on the underwater surface.

In certain embodiments, the submersible apparatus comprises a yet further tool being operable to perform maintenance operations on the underwater surface.

More specifically, the yet further tool may be operable to perform one or more of the following operations on the underwater surface: cathodic protection application and/or contact cleaning.

In embodiments where the platform is a submersible vehicle or a part thereof, the submersible apparatus may further comprise attachment means operable to locate the submersible vehicle at the surface to be cleaned.

The attachment means operable to locate the submersible vehicle at the underwater surface may comprise a thruster. More specifically, the thruster may be a brushless DC thruster. In embodiments of the invention, the thruster is operable to provide thrust in either the horizontal and/or the vertical direction. In this way, the submersible vehicle is manoeuvrable in the body of water in which the vehicle is operating to locate the vehicle at the underwater surface. The attachment means operable to locate the submersible vehicle at the underwater surface may be further operable to attach the submersible vehicle to the underwater surface.

More specifically, the attachment means may comprise a magnetic attachment device. The magnetic attachment device is preferably operable to attach the submersible vehicle to an underwater surface. By way of example, the underwater surface may by a metallic hull of a vessel.

Alternatively, the attachment means may comprise a non-magnetic attachment device. More specifically, the non-magnetic attachment device may comprise a suction device. The suction device is preferably operable to attach the submersible vehicle to an underwater surface. More specifically, the suction device is operable to attach the submersible vehicle to the underwater surface by generating an attractive force through a vortex. The suction device preferably comprises an impeller having a skirt about an edge thereof, the impeller being operable to rotate and to draw water up to the centre thereof. The water is forced laterally from the centre of the impeller towards the skirt at an edge of the impeller.

Thereafter, water is forced perpendicularly down away from the impeller by the skirt where it is, once more, drawn up to the centre of the impeller. An exemplary suction device suitable for use in the present invention is disclosed in International Patent Application No PCT/USOO/29664 (Publication No WO01/33084). A submersible vehicle having such a suction device is available from Seabotix, Inc.

When the submersible apparatus comprises attachment means operable to attach the submersible vehicle to an underwater surface, the at least one nozzle position may be readily controlled relative to the underwater surface.

According to a second aspect, the present invention provides a submersible vehicle comprising: attachment means operable to locate the submersible vehicle at an underwater surface; at least a first equipment attachment port configured to receive a first tool, and at least a first tool operable to inspect an underwater surface and being connectable to the first equipment attachment port, the submersible vehicle further comprising a second equipment attachment port configured to receive a second tool, and a second tool operable to perform an operation on an underwater surface and being connectable to the second equipment attachment port.

In preferred embodiments of the invention, the submersible vehicle is a remotely operated vehicle (ROV).

The attachment means operable to locate the submersible vehicle at an underwater surface may comprise a thruster. More specifically, the thruster may be a brushless DC thruster. In embodiments of the invention, the thruster is operable to provide thrust in either the horizontal and/or the vertical direction. In this way, the submersible vehicle is manoeuvrable in the body of water in which the vehicle is operating to locate the vehicle at the underwater surface.

The attachment means operable to locate the submersible vehicle at an underwater surface may be further operable to attach the submersible vehicle to the underwater surface.

More specifically, the attachment means may comprise a magnetic attachment device. The magnetic attachment device is preferably operable to attach the submersible vehicle to an underwater surface. By way of example, the underwater surface may by a metallic hull of a vessel. Alternatively, the attachment means may comprise a non-magnetic attachment device. More specifically, the non-magnetic attachment device may comprise a suction device. The suction device is preferably operable to attach the submersible vehicle to an underwater surface. More specifically, the suction device is operable to attach the submersible vehicle to the underwater surface by generating an attractive force through a vortex. The suction device preferably comprises an impeller having a skirt about an edge thereof, the impeller being operable to rotate and to draw water up to the centre thereof. The water is forced laterally from the centre of the impeller towards the skirt at an edge of the impeller. Thereafter, water is forced perpendicularly down away from the impeller by the skirt where it is, once more, drawn up to the centre of the impeller. An exemplary suction device suitable for use in the present invention is disclosed in International Patent Application No PCT/USOO/29664 (Publication No WO01 /33084). A submersible vehicle having such a suction device is available from Seabotix, Inc.

When the submersible vehicle comprises attachment means operable to attach the submersible vehicle to an underwater surface, the first and the second tool position may be readily controlled relative to the underwater surface.

In embodiments of the invention, the first and the second equipment attachments ports may be one and the same, Alternatively, the first and the second equipment ports may be separate.

In embodiments of the invention wherein the first and the second equipment attachments ports are one and the same, the submersible vehicle may further comprise a tool adapter configured to receive at least the first and the second tools. In this way, a single equipment attachment port maybe arranged to receive both or all of the tools attachable to the submersible vehicle. Thus, the submersible vehicle is arranged to have a simple footprint to minimise manufacturing complexity and cost.

In embodiments of the invention, the first tool is operable to inspect the underwater surface. More specifically, the first tool may be operable to provide continuous measurements of a parameter associated with the underwater surface.

The first tool may be a 3D image generation device.

More specifically, the 3D image generation device may comprise a video camera.

Alternatively, or in addition, the first tool may comprise an acoustic resonance testing device operable to inspect the condition of the underwater surface. In particular, the acoustic resonance testing device is operable to produce acoustic resonance which, in use, is used to detect areas of corrosion on the underwater surface and/or areas of marine growth and debris build-up. The acoustic resonance testing device may be further or alternatively operable to detect thickness of specified areas of an underwater surface to determine if it has been worn or degraded. The acoustic resonance testing device is preferably operable to scan the underwater surface and to provide a 3D image of the scanned surface. In this way, irregularities in the underwater surface are detectable.

Alternatively, or in addition, the first tool may be operable to inspect the underwater surface and to provide one or more of: ultrasonic thickness measurements and/or resonance thickness measurements and/or cathodic protection thickness measurements allowing accurate thickness measurements to be made at locations on the underwater surface

In preferred embodiments of the present invention, the second tool is operable to perform maintenance operations on the underwater surface

More specifically, the second tool may be operable to perform one or more of the following operations on the underwater surface cathodic protection application and/or cleaning

In preferred embodiments, the second tool is a cleaning tool operable to perform a cleaning operation on the underwater surface

In much preferred embodiments, the cleaning tool comprises a fluid delivery means More specifically, the fluid delivery means comprises a nozzle in fluid communication with a fluid delivery line which may , in turn, be in fluid communication with a fluid containment tank Alternatively, the fluid delivery line may be in fluid communication with a fluid supply source More specifically the fluid supply source may be a body of water, for example

More specifically, the nozzle may be a fan-type nozzle In this way, fluid emanating from the fan-type nozzle is projected over a wide area of the underwater surface

Alternatively, the nozzle may be a single opening, straight delivery nozzle whereby the stream of fluid emanating from the nozzle is directed straight at the underwater surface In this way a relatively small area of the underwater surface may be targeted and more precise cleaning is facilitated.

As a further alternative, the nozzle may comprise an array of smaller nozzle heads each being operable to deliver fluid therefrom. The array by be a plurality of nozzle heads in horizontal alignment with one another. In this way, a single fluid delivery line may be in fluid communication with all of the fluid heads. Thus, a wide area of the underwater surface may be cleaned. The array may alternatively comprise a number of discrete nozzle heads each being individually in fluid communication with a fluid delivery line. In this way, more powerful cleaning may be provided at each nozzle head. Furthermore, each nozzle head is independently controllable in terms of fluid delivery rate and pressure.

It is much by preference that the cleaning tool is a cavitational cleaning device. An exemplary cavitational cleaning device is the CaviBlaster™ available from CaviDyne, lnc (USA).

In embodiments of the invention wherein the second tool is a cavitational cleaning device, the cavitational cleaning device preferably comprises a nozzle.

The nozzle is preferably locatable relative to the underwater surface, such that the angle between the underwater surface and the longitudinal axis of the nozzle is in the range of 20 to 45 degrees.

Further, in such embodiments, the nozzle is locatable relative to the underwater surface such that a distance (d) between the end of the nozzle and the underwater surface is between 35mm and 80mm. Preferably the distance d is between 50mm and 76mm. The distance d is measured parallel to the longitudinal axis of the nozzle from the centre of the opening in the nozzle end. If the distance d is less than 35mm, the cleaning capability of the cleaning tool is reduced.

Preferably, the cleaning tool is operable to deliver a non-abrasive cleaning material to the underwater surface.

The non-abrasive cleaning material is preferably a pressurized fluid. More specifically, the non-abrasive cleaning material is a a pressurised liquid. Even more specifically, the non-abrasive cleaning material is pressurized water.

The non-abrasive cleaning material is preferably a composition of delivered at the nozzle end at a pressure of between 1500 and 4000psi.

When referring to a "non-abrasive" cleaning material is should be understood that the cleaning material should leave the coating on the underwater surface substantially intact. In particular embodiments, the anti-fouling coating on an underwater surface would be left substantially intact, if not completely intact, after application of the non-abrasive cleaning material thereto.

In embodiments of the invention, the first and/or the second equipment attachment port(s) comprises a bracket operable to retain the second tool in fixed position relative to the underwater surface.

More specifically, the bracket may comprise one or more U-shaped brackets. When the bracket comprises more than one U-shaped brackets, the bracket comprises two opposing U-shaped clamp members which, when joined together, form an O-shaped clamp. In this way, the second tool may be clamped between the U-shaped brackets and thereby held in position.

Alternatively, the bracket may comprise a single U-shaped bracket and one or more retaining means. The second tool may be positioned in the U-shaped bracket and held in place by the retaining means. The retaining means may be one or more clamps, attachable to opposing sides of the U- shaped bracket.

In use of the bracket, the second tool is held in a fixed position relative to the underwater surface. In this way, when the second tool is a cavitational cleaning tool, the distance d and the angle (α) of the nozzle head relative to the surface to be cleaned is maintained and constant, thus, maximising the cleaning efficiency of the second tool.

According to a third aspect there is provided a method of cleaning an underwater surface comprising the steps:

(a) locating a submersible apparatus at an underwater surface in a body of water;

(b) providing a pressurised fluid and delivering the pressurised fluid through at least one nozzle configured to induce cavitation in the body of water;

(c) inducing cavitation in the body of water between the at least one nozzle and the underwater surface;

(d) cleaning the underwater surface by way of cavitation.

It is preferred that the submersible apparatus is according to the first aspect of the invention. It is alternatively preferred that the submersible apparatus is a submersible vehicle according to the second aspect

According to a fourth aspect, there is provided a method of inspecting an underwater surface and of undertaking operations relating to the underwater surface following the inspection, the method comprising the steps of locating a submersible vehicle at an underwater surface which underwater surface is located in a body of water, inspecting the underwater surface using a first tool, providing a second tool on the submersible vehicle, the second tool being operable to perform an operation on the underwater surface, remotely activating the second tool and performing the operation of the second tool on the underwater surface

It is preferred that the submersible vehicle is according to the second aspect

In embodiments of the invention, the inspection of the underwater surface by the first tool comprises imaging the underwater surface More specifically, the imaging may comprise one or more of video image recording, ultrasonic thickness measurement scanning, acoustic resonance scanning, cathodic protection measurement, or the like

In preferred embodiments of the invention, the operation of the second tool is a cleaning operation More specifically, the operation of the second tool is cavitational cleaning More specifically, a cavitational cleaning tool is provided on the submersible vehicle The cavitational cleaning tool is preferably operable to deliver a non-abrasive fluid composition to the underwater surface, which fluid composition is delivered from the tool at pressure Preferably the fluid composition is delivered at pressures of between 1500 and 4000psι

In preferred embodiments, the submersible vehicle is attached to the underwater surface

In these embodiments, the second tool is located at a fixed position relative to the underwater surface More specifically, the second tool is located at a fixed angle α and at a fixed distance, d, from the underwater surface Preferably the fixed angle α is between 20 and 45 degrees

Preferably distance, d, is between 35mm and 80mm In this way, and particularly when the second tool is a cavitational cleaning tool, the position of the second tool relative to the underwater surface may be precisely controlled

In preferred embodiments of the invention, the steps of inspecting the underwater surface and of remotely activating the second tool are completed without the submersible vehicle being surfaced in the body of water

It is much by preference that the underwater surface is a hull of a vessel, or the like More specifically, the underwater surface is preferably the hull of a vessel in a body of water

In this way, a vessel may be inspected and cleaned, for example, at its operational location, i e in situ as opposed to bringing the vessel into dry- dock Furthermore, the use of a submersible vehicle operable to clean a vessel hull in situ means that there is no longer a need to deploy divers at great cost and in harsh, potentially dangerous situations It will be understood that features described with respect to one of the aspects of the invention above, are equally applicable to any one or more of the other aspects of the invention.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description of embodiments and upon reference to the accompanying drawings, in which:

Figure 1 is a schematic representation of a submersible apparatus according to an embodiment of the first aspect of the invention;

Figure 2 is a schematic front plan view of a manifold for attachment to the submersible apparatus of Figure 1 ;

Figure 3 is a schematic front perspective view of a manifold for attachment to the submersible apparatus of Figure 1 ; Figure 4 is a schematic front perspective view of a manifold and adjustable bracket for attachment to the submersible apparatus of Figure 1;

Figure 5 is a schematic representation of a submersible vehicle according to an embodiment of the second aspect of the invention;

Figure 6 is a plan view of the submersible vehicle of Figure 5;

Figures 7 is a plan view of an alternative embodiment of a submersible vehicle according to the second aspect of the invention;

Figure 8 is a schematic representation of a tool attachable to a submersible vehicle of the second aspect of the present invention;

Figure 9 shows an embodiment of an equipment attachment port of a submersible vehicle according to the second aspect of the invention;

Figures 10a, 10b and 10c show alternative embodiments of an equipment attachment port of a submersible vehicle according to the second aspect of the invention; and

Figures 11 shows a further alternative embodiment of an equipment attachment port of a submersible vehicle according to the second aspect of the invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Further, although the invention will be described in terms of specific embodiments, it will be understood that various elements of the specific embodiments of the invention will be applicable to all embodiments disclosed herein.

Where possible and appropriate, like components are depicted by the same reference numeral throughout the accompanying figures.

Figure 1 depicts a submersible apparatus, generally depicted by the reference numeral 20. The submersible apparatus comprises a platform in the form of submersible vehicle 1.

The submersible vehicle 1 has skids 2 which locate the submersible vehicle 1 at an underwater surface to be cleaned 3. It will be understood that alternative propulsion devices may be used in addition to or, indeed, as an alternative to skids 2. For example, the skids 2 may be replaced by tracks or the like.

Although not shown in the depicted embodiment, it is much preferred that the submersible vehicle 1 is attached to the underwater surface 3 with a suction device 10 in the form of an impeller. The submersible vehicle 1 has a video recorder attachment port (not shown) into which a video camera is attached. The video camera is operable to inspect the underwater surface 3 and to transmit the video images collected by the camera back to an operator on the surface of the body of water in which the submersible vehicle 1 is located. The submersible vehicle 1 further has a bracket 4 configured to receive a cavitational cleaning nozzle 5. The cavitational cleaning nozzle 5 is connected to the bracket 4 and has a nozzle fluid outlet end 6 and a longitudinal axis 7. The submersible vehicle 1 is preferably a remotely operated vehicle (ROV).

The ROV 1 is initially manoeuvred into position using thrusters (not shown) located on the ROV 1. The ROV 1 is then attached to the underwater surface 3 such that the nozzle fluid outlet end 6 is a pre- determined distance d from underwater surface 3. Throughout operation of the ROV 1 , pre-determined distance d will be constant. Further, bracket 4 maintains a pre-determined angle α between the underwater surface 3 and the longitudinal axis 7 of the cavitational cleaning nozzle 5 of the ROV 1. The pre-determined distance d is preferably between 35mm and 80mm and pre-determined angle α is preferably between 25 and 45 degrees. In this way, maximum cleaning efficiency is ensured.

In an exemplary embodiment, nozzle 5 is in fluid communication with a fluid mixing manifold via fluid delivery line 8. Pressurised fluid in the form of pressurised water is received by the fluid mixing manifold 21 from a fluid containment tank containing water. The water in the containment tank is delivered to the manifold by a pump (not shown). Other fluid delivery and mixing devices are envisaged and should be taken to be within the scope of the present invention. Further, the fluid containment tank may be replaced or supplemented by an alternative fluid supply source. In particularly preferred embodiments, the fluid supply source is the body of water itself. The body of water may be the ocean, a lake, a river or an industrial cooling pond. The manifold 21 has a fluid inlet port 23 and at least one fluid outlet port 25. The fluid outlet port 25 of the manifold being in fluid communication with the nozzle 5 via a flexible hose conduit 27.

Other operational lines are connected to the ROV 1 through tether 9.

By attaching ROV 1 to underwater surface 3, a stable platform is provided to assist in cleaning the underwater surface 3 to remove marine growth and debris. The suction device 10 is operable to provide a vortex between skirts 11 depending from the edge of the suction device 10. The vortex is created by an impeller device which creates an attractive force between the ROV 1 and the underwater surface 3. The ROV 1 is attached to the underwater surface 3 by the suction device 10. Thereafter the ROV 1 is manoeuvrable across the underwater surface 3 under remote direction from a pilot.

As best seen in Figure 2, manifold 21 comprises a number of fluid outlet ports 25, each of which may be releasably coupled with a nozzle 5 having a nozzle outlet port 29 at a centre thereof. Nozzle 5 is coupled into the manifold fluid outlet port 25 using a screw threaded arrangement. This allows for easy replacement and cleaning of the nozzle 5 by an operative. Although not shown, each manifold outlet port 25 may receive a blank stopper in place of a nozzle 5. In this way, the surface area to be cleaned can be defined by the operator.

Nozzles 5 are in fixed orientation with respect to one another. Distance A may be 33mm and the manifold length B 770mm in embodiments wherein the array of nozzles 5 comprises 5 nozzles 5. The manifold height C in the depicted embodiment is 38mm. It will be understood that the number and spacing of the nozzles within the manifold is arbitrary, however, it is much preferred that there be more than one nozzle. In this way, a greater surface area of underwater surface 3 can be cleaned during a single sweep of the apparatus 20 than could be achieved using a single nozzle arrangement. For example, in an alternative embodiment, A may be 100mm, B may be 900mm and C may be 75mm

Figure 3 shows manifold 21 in perspective view. Pressurised water is pumped through the fluid delivery line to the fluid inlet port 23 of manifold 21. Nozzles 5 are threaded into fluid outlet ports 25. The manifold 21 is bolted to the platform (not shown) using threaded bolts through bolt holes 31. The angle α may initially be adjustable by having adjustable bolts holes on the platform (not shown). Once determined, angle α is fixed at between 25 and 45° The angle α is measured between the longitudinal axis 7 of nozzle 5 and the underwater surface 3. The platform serves to locate the nozzle at angle α and pre-determined distance d from the underwater service 3. The manifold 21 may have a blank end hole 33 at either end thereof, which blank hole(s) 33 in normal operation are stoppered to prevent fluid flow therethrough.

It is preferred that the manifold 21 is formed of a material able to withstand a marine and/or underwater environment. The manifold may be, for example, aluminium, stainless steel, ceramic, plastic or other suitable material.

In Figure 4, the submersible apparatus 20 comprises both a manifold 21 and a bracket A'. The fluid outlet ports 25 of the manifold are in fluid communication with nozzles 5 via a flexible hose 27. Manifold 21 and bracket 4¹ are each mountable on the platform (now shown). Figure 5 shows a submersible vehicle 1 having skids 2 which locate the submersible vehicle 1 at an underwater surface 3. Although not shown in the depicted embodiment, it is much preferred that the submersible vehicle 1 is attached to the underwater surface 3 with a suction device 10 in the form of an impeller. The submersible vehicle 1 has a video recorder attachment port (not shown) into which a video camera is attached. The video camera is operable to inspect the underwater surface 3 and to transmit the video images collected by the camera back to an operator on the surface of the body of water in which the submersible vehicle 1 is located. The submersible vehicle 1 further has a second equipment attachment port in the form of bracket 4 configured to receive a second tool. In the depicted embodiment, the second tool is a cavitational cleaning nozzle 5. The cavitational cleaning nozzle 5 is connected to the bracket 4 and has a nozzle end 6 and a longitudinal axis 7. The submersible vehicle 1 is preferably a remotely operated vehicle (ROV). The ROV 1 is initially manoeuvred into position using thrusters (not shown) located on the ROV 1. The ROV 1 is then attached to the underwater surface 3 such that the nozzle end 6 is a fixed distance d from underwater surface 3. Throughout operation of the ROV 1, distance d will be constant. Further, bracket 4 maintains an angle α between the underwater surface 3 and the longitudinal axis 7 of the ROV 1. When the nozzle 5 is a cavitational cleaning tool, the distance d is preferably between 35mm and 80mm and angle α is preferably between 25 and 45 degrees. In this way, maximum cleaning efficiency is ensured. In an exemplary embodiment, nozzle 5 is in fluid communication with a fluid mixing manifold via fluid delivery line 8. Fluid is received by the fluid mixing manifold from a tank containing water. Other fluid delivery and mixing devices are envisaged and should be taken to be within the scope of the present invention. Other operational lines are connected to the ROV 1 through tether 9. By attaching ROV 1 to underwater surface 3, a stable platform is provided to assist in cleaning the underwater surface 3 to remove marine growth and debris. The suction device 10 is operable to provide a vortex between skirts 11 depending from the edge of the suction device 10. The vortex is created by an impeller device which creates an attractive force between the ROV 1 and the underwater surface 3. The ROV 1 is attached to the underwater surface 3 by the suction device 10. Thereafter the ROV 1 is manoeuvrable across the underwater surface 3 under remote direction from a pilot.

Figure 6 shows an ROV 1 with a nozzle 5 connected to an alternative nozzle end 60. The nozzle end 60 may be a single fluid delivery nozzle or may, alternatively and as depicted provide a plurality of fluid delivery points. In this arrangement, a wider surface area of the underwater surface may be cleaned at the same time.

Figure 7 shows an ROV 1 with an alternative bracket 40 having two attachment points on the ROV 1 and providing a support and attachment port for a nozzle 500 having multiple nozzle heads 600.

Figure 8 shows nozzle 5 without ROV 1. Nozzle 5 has a nozzle end 6 which may be a fan-type end or a straight head end. The nozzle 5 is locatable on an ROV such that the longitudinal axis 7 and the nozzle end 6 are in fixed position relative to underwater surface 3 to which the ROV is attached. Thus, in use, angle α and distance d remain constant.

Figure 9 shows an alternative bracket arrangement 400. The bracket 400 is U-shaped in order that nozzle 5 be received within the bracket 400. The nozzle 5 is retained in position within the bracket 400 by one or more retaining means. In the depicted embodiment, there are three retaining ties 401.

Figures 10a to 10c show alternative arrangements of brackets 400a, 400b, 400c suitable for attachment to an ROV 1 of the present invention.

Bracket 400a is mountable on an ROV by three bolt holes 402. Nozzle 5 is received on bracket 400a on projection 403 through which projection fluid may be delivered to nozzle 400a.

Bracket 400b is an alternative U-shaped bracket attachable to the ROV by plate 405 and screw threaded bolts 406.

Bracket 400c comprises a plate 407 attachable to the ROV with screw threaded bolt 408 and connected to nozzle 5 via arm 409.

Figure 11 shows a yet further alternative bracket 4000 operable to retain nozzle 5 in fixed location relative to an underwater surface. Bracket 4000 comprises a pair of opposing U-shaped clamps 4000a and 4000b. The opposing clamps 4000a and 4000b are brought together about nozzle 5 and fastened into position with bolts 4001. The nozzle 5 is spaced apart from opposing clamps 4000a and 4000b by a rubber gasket 4002 in order to reduce movement and therefore wear on the nozzle when the ROV is operating.

In operation of a submersible apparatus and/or vehicle of the invention, a visual inspection of the surface of the structure/item will be conducted using the ROV (Remotely Operated Vehicle) using an inspection tool. Data from the inspection tool will be recorded and given to the client for analysis. If significant amounts of marine growth and debris are found on the surface of the structure requiring cleaning a ROV (Remotely Operated Vehicle) is initially free flown to be suitable submerged location. A small section of the structure is cleaned to allow the ROV to be attached to the structure. Once the ROV (Remotely Operated Vehicle) has adhered to the structure the ROV (Remotely Operated Vehicle) is advanced along the structure/item cleaning the surface of marine growth and debris using high pressure liquid, such as water, delivered from a cleaning nozzle retained at a fixed angle and distance from the surface using a bracket which may be welded or bolted, or both, to the ROV. A single cleaning nozzle or multiple nozzles may be attached to the bracket which bracket is attached to the ROV (Remotely Operated Vehicle) by bolts. It is advantageously that the nozzle be set at an angle between 25 degrees and 45 degrees and approx 2 to 3 inches away from the structure/item to be cleaned.

When the process is complete the visual inspection of the structure/item is repeated using the ROV (Remotely Operated Vehicle) with data recorded and given to the client for analysis.

Cleaning of the whole surface can be undertaken in the case of ships, where weight and friction caused by fouling is detrimental to the performance of the vessel and this can be done without the use of a dry dock and therefore major expense. In the case of static or permanent structures, cleaning facilitates greater visibility of the structure for inspection purposes or a reduction in weight.

A stepwise method for cleaning an underwater surface will now be described. Initially, a suitable location is determined as start point for the cleaning operation. A shelter i.e. in a form purpose built container or a make shift portable tent, is erected to give protection from the elements and better visibility on a viewing monitor for the operator(s). Power lines are provided to the ROV (Remote Operated Vehicle) work site either from a land supply, vessel supply or generator supply, or the like. Communication lines are established to the bridge or control room as required. Suitable communication lines may be radio communications, for example. A manual or mechanical means (crane) is used to locate the high pressure liquid, such as water, cleaning equipment and the ROV at the worksite.

Subsequently, connections are established between the incoming power line to a topside control unit. Control and power line connections from the topside control unit to the winch slip rings are made thus providing the ROV the power and communications required for operations.

Once all connections have been established, power up of the ROV and cleaning equipment is done and a full set of deck checks completed. Deck checks require checking of all of the systems which an ROV needs to perform its duties, .i.e. checks cameras, thrusters, lights and crawler skid.

On completion of a satisfactory deck check, the bracket is installed onto the host ROV to fix the high pressure liquid cleaning nozzle(s) onto the ROV. The size of the bracket and quantity of holding bolts/nuts will depend on the host ROV. The bracket could be fitted to the front or rear of the host ROV depending on circumstances or conflicting operations. In fact, the bracket may be mountable anywhere on the ROV as required. In certain embodiments it has been found to be advantageous to locate to bracket on the underside of the ROV close to the centre of gravity thereof.

Once the equipment bracket has been fitted to the host ROV₁ the high pressure liquid cleaning nozzle or multiple nozzles can be fitted to the bracket using a clamping system to achieve the correct angle between 25 and 45 degrees and distance 2 to 3 inches to the surface to be cleaned. A high pressure hose(s) is connected to the nozzle(s) which can be secured by various means to the host ROV umbilical/tether. The umbilical/tether provides power and communications from surface control unit to ROV. The umbilical is made up of power conductors and fibre optics).

The high pressure hose(s) will be secured at various points along the umbilical/tether depending on the amount of high pressure hose(s) and nozzles required.

Initially, 2-3 metres of hose(s) can be secured to the umbilical/tether with the remainder of the hose(s) being attached during launching of the ROV into the water. As a result, the amount of deck space required for this operation is minimised.

In the subsequent steps, the water feed (suction) for the high pressure liquid cleaning equipment is lowered into the surrounding body of water i.e. into the ocean, sea, river, lake, or the like.

In certain circumstances, and depending on the work site, before

ROV/Cleaning commences it will be important to ensure that operations are not going to conflict with the intended ROV/cleaning operations. For example, on a vessel, ensure sea water intakes are diverted to the opposite side of the location to be cleaned. Once clearance to commence ROV/cleaning work has been granted, the deployment of the host ROV can be performed by manual or mechanical means. Once launch procedures have commenced, on the deploying the host ROV overboard, the high pressure liquid hose(s) can continuously be attached to the tether/umbilical until enough tether/umbilical had been paid out to do the task. The hose(s) will be attached to the tether/umbilical by the use of elasticised cord or other suitable means.

Before the host ROV reaches the body of water, the power is switched on to the host ROV. This operation provides a final check to test power and communications.

Once the host ROV is in the water, the task is located by visual means using sonar or navigation sensors. By using the topside controls, the host ROV operator will pilot/fly the ROV to the work site. By using the topside controls the host ROV operator will pilot/fly the host ROV on a general visual inspection (GVI) of the surface or item to be cleaned; this operation will identify any problem areas and will give good video evidence of growth patterns or damage on the surface/structure. The video footage will be recorded to DVR (Digital Video Recorder) or HDD (Hard Disk Drive), for example.

In order to commence cleaning operations, the host ROV operator will need to clean a small area to enable the host ROV to adhere to the said surface or item. Once the host ROV is in position, the high pressure liquid cleaning power plant is started.

The cleaning medium is provided through the hose(s) to the nozzle(s) attached to the bracket interface which in turn is attached to the host ROV. Using the topside controls, the operator can move into position and attach the host ROV to the surface or item.

Once fixed into position, using the crawler skid (Vortex VRAM Technology), the high pressure liquid cleaning power plant can be started. Once cleaning effect has been observed, cleaning operations may begin. The host ROV operator will start the cleaning operations using the topside control unit to control the host ROV. Host ROV speed will depend on the extent of marine growth pre- set parameters for cleaning.

The host ROV is operated until the cleaning task is complete.

Once cleaning is completed, the high pressure liquid, power plant will be switched off and the host ROV operator, using the topside controller, will release the host ROV from the surface or item.

After cleaning has been completed, using the topside controls, the host ROV operator will pilot/fly the host ROV on a general visual inspection (GVI) of the surface or item which has been cleaned, this will identify any problem areas and will also give evidence that the surface or item has been cleaned and inspected to required standards. Further, video footage will be recorded to DVR (Digital Video Recorder) or HDD (Hard Disk Drive). Video footage may be recorded from the time when the host ROV enters the water until it returns after the task has been completed. The host ROV can now be recovered to surface. In order to do so the host ROV operator will pilot the host ROV away from the surface or item and the host ROV can be recovered by manual or mechanical means.

On recovery to the surface, the high pressure liquid hose(s) can be removed from the umbilical/tether as and when the high pressure liquid hose(s) is attached.

Once the host ROV is back on dry land, power can be isolated and power and communication lines that were mated can now be disconnected and stored. The high pressure liquid, cleaning equipment feed can be recovered to the surface of the body of water and be stowed in its correct position.

Finally, the shelter or container can be vacated, in the case of shelter this can be packed away and put in its packing case.

Claims

1. A submersible apparatus locatable at a surface to be cleaned, said surface being located in a body of water, the apparatus comprising, a fluid delivery line in fluid communication with a fluid outlet port, the fluid outlet port comprising at least one nozzle configured to induce cavitation in the body of water when a pressurised fluid is passed therethrough, and a platform adapted to locate the at least one nozzle at a pre-determined angle and a pre-determined distance from the surface to be cleaned.

2. A submersible apparatus according to claim 1 , wherein the at least one nozzle comprises a fluid inlet, a fluid outlet and a fluid flow channel therebetween.

3. A submersible apparatus according to claim 1 or claim 2, wherein the submersible apparatus comprises a plurality of nozzles.

4. A submersible apparatus according to any one of claims 1 to 3, wherein the plurality of nozzles are each located at a pre-determined angle and/or a pre-determined distance from the surface to be cleaned.

5. A submersible apparatus according to any one of claims 1 to 4, wherein each one of the plurality of nozzles is in fixed orientation with respect to each of the other of the plurality of nozzles.

6. A submersible apparatus according to any one of claims 3 to 5, wherein the nozzle fluid outlets are in horizontal alignment with one another.

7. A submersible apparatus according to any one of claims 3 to 5, wherein the plurality of nozzles comprises a number of discrete nozzle fluid outlets each being individually in fluid communication with a fluid delivery line.

8. A submersible apparatus according to any one of the preceding claims, wherein the submersible apparatus is moveable with respect to the surface to be cleaned during the cleaning operation.

9. A submersible apparatus according to claim 8, wherein the submersible apparatus is moveable with respect to the surface to be cleaned whilst maintaining the at least one nozzle at the pre-determined angle and the pre-determined distance from the surface to be cleaned.

10. A submersible apparatus according to any one of the preceding claims, wherein the at least one nozzle is locatable relative to the underwater surface to be cleaned, such that the pre-determined angle (α) between the underwater surface and the longitudinal axis of the at least one nozzle is in the range of 20 to 45 degrees.

11. A submersible apparatus according to any one of the preceding claims, wherein the at least one nozzle is locatable relative to the underwater surface such that a pre-determined distance (d) between the fluid outlet of the nozzle and the underwater surface is between 35mm and 80mm.

12. A submersible apparatus according to any one of the preceding claims, wherein the submersible apparatus is engageable against the surface to be cleaned.

13. A submersible apparatus according to claim 12, wherein the submersible apparatus is engageable against the surface to be cleaned and thereafter is moveable with respect to the surface to be cleaned whilst remaining engaged against the surface to be cleaned.

14. A submersible apparatus according to any one of the preceding claims, wherein the platform is a submersible vehicle or a part thereof.

15. A submersible apparatus according to claim 14, wherein the platform is a submersible remotely operated vehicle (ROV) or a part thereof.

16. A submersible apparatus according to any one of the preceding claims, wherein the at least one nozzle is fixed in position relative to the platform.

17. A submersible apparatus according to any one of claims 14 to 16, wherein the distance between the nozzle fluid outlet and the centre point of the submersible vehicle or part thereof is fixed and constant.

18. A submersible apparatus according to any one of the preceding claims 3, wherein the platform is a rigid member.

19. A submersible apparatus according to claim 18, wherein the platform is a strut on a submersible vehicle.

20. A submersible apparatus according to any one of the preceding claims, wherein the at least one nozzle is mountable on the platform.

21. A submersible apparatus according to claim 20, wherein the at least one nozzle may be directly mountable on the platform.

22. A submersible apparatus according to claim 20, wherein the at least one nozzle is indirectly mountable on the platform.

23. A submersible apparatus according to claim 22, wherein the at least one nozzle is mounted on a bracket with the bracket being mountable on the platform.

24. A submersible apparatus according to any one of the preceding claims, wherein the submersible apparatus further comprises a manifold.

25. A submersible apparatus according to claim 24, wherein the manifold comprises a single fluid inlet port in fluid communication with the fluid delivery line.

26. A submersible apparatus according to claim 24, wherein the manifold comprises a plurality of fluid inlet ports each in fluid communication with a fluid delivery line.

27. A submersible apparatus according to any one of claims 24 to 26, wherein the manifold comprises the one or more fluid outlet ports.

28. A submersible apparatus according to claim 27, wherein the or each manifold fluid outlet port is releasably coupleable with a nozzle.

29. A submersible apparatus according to any one of claims 24 to 28, wherein the manifold is attached to the platform.

30. A submersible apparatus according to any one of claims 24 to 28, wherein the manifold is attachable to the platform.

31. A submersible apparatus according to any one of the preceding claims, wherein the pressurised fluid is a liquid.

32. A submersible apparatus according to any one of the preceding claims, wherein the submersible apparatus further comprises an inspection tool.

33. A submersible apparatus according to claim 32, wherein the inspection tool is a 3D image generation device.

34. A submersible apparatus according to claim 32 or claim 33, wherein the inspection tool comprises an acoustic resonance testing device operable to inspect the condition of the underwater surface.

35. A submersible apparatus according to any one of claims 32 to 34, wherein the inspection tool is operable to inspect the underwater surface and to provide one or more of: ultrasonic thickness measurements and/or resonance thickness measurements and/or cathodic protection thickness measurements allowing accurate thickness measurements to be made at locations on the underwater surface.

36. A submersible vehicle comprising: attachment means operable to locate the submersible vehicle at an underwater surface; at least a first equipment attachment port configured to receive a first tool, and at least a first tool operable to inspect an underwater surface and being connectable to the first equipment attachment port, the submersible vehicle further comprising a second equipment attachment port configured to receive a second tool, and a second tool operable to perform an operation on an underwater surface and being connectable to the second equipment attachment port.

37. A submersible vehicle according to claim 36, wherein the submersible vehicle is a remotely operated vehicle (ROV).

38. A submersible vehicle according to claim 36 or claim 37, wherein the attachment means operable to locate the submersible vehicle at an underwater surface comprise a thruster.

39. A submersible vehicle according to any one of claims 36 to 38, wherein the attachment means operable to locate the submersible vehicle at an underwater surface are further operable to attach the submersible vehicle to the underwater surface.

40. A submersible vehicle according to claim 39, wherein the attachment means comprise a magnetic attachment device.

41. A submersible vehicle according to claim 39, wherein the attachment means comprise a non-magnetic attachment device.

42. A submersible vehicle according to claim 41, wherein the non- magnetic attachment device comprises a suction device.

43. A submersible vehicle according to any one of claims 39 to 42, wherein the first and the second tool position are readily controlled relative to the underwater surface.

44. A submersible vehicle according any one of the preceding claims, wherein the first and the second equipment attachments ports are one and the same.

45. A submersible vehicle according to any one of claims 36 to 43, wherein the first and the second equipment ports are separate.

46. A submersible vehicle according to claim 45, wherein the submersible vehicle further comprises a tool adapter configured to receive at least the first and the second tools.

47. A submersible vehicle according to any one of the preceding claims, wherein the first tool is operable to inspect the underwater surface.

48. A submersible vehicle according to claim 47, wherein the first tool is operable to provide continuous measurements of a parameter associated with the underwater surface.

49. A submersible vehicle according to claim 47 or claim 48, wherein the first tool is a 3D image generation device.

50. A submersible vehicle according to any one of the preceding claims, the second tool is operable to perform maintenance operations on the underwater surface.

51. A submersible vehicle according to claim 50, wherein the second tool is operable to perform one or more of: cathodic protection application and/or cleaning.

52. A submersible vehicle according to any one of the preceding claims, wherein the second tool is a cleaning tool operable to perform a cleaning operation on the underwater surface.

53 A submersible vehicle according to claim 52, wherein the cleaning tool comprises a fluid delivery means

54 A submersible vehicle according to claim 53, wherein the fluid delivery means comprises a nozzle in fluid communication with a fluid delivery line

55 A submersible vehicle according to any one of claims 52 to 54, wherein the second tool is a cavitational cleaning device comprising a nozzle

56 A submersible vehicle according to claim 55, wherein the nozzle is locatable relative to the underwater surface, such that the angle between the underwater surface and the longitudinal axis of the nozzle is in the range of 20 to 45 degrees

57 A submersible vehicle according to claim 55 or claim 56, wherein the nozzle is locatable relative to the underwater surface such that a distance (d) between the end of the nozzle and the underwater surface is between 35mm and 80mm

58 A submersible vehicle according to any one of claims 52 to 57, wherein the cleaning tool is operable to deliver a non-abrasive cleaning material to the underwater surface

59 A submersible vehicle according to claim 58, wherein the non- abrasive cleaning material is a pressurized fluid

60 A submersible vehicle according to claim 58 or claim 59, wherein the non-abrasive cleaning material is pressurized water

61 A submersible vehicle according to any one of the preceding claims, wherein the first and/or the second equipment attachment port(s) comprises a bracket operable to retain the second tool in fixed position relative to the underwater surface

62 A submersible vehicle according to claim 61 , wherein the bracket comprises one or more U-shaped brackets

63 A submersible vehicle according to claim 62, wherein the bracket comprises a single U-shaped bracket and one or more retaining means

64 A method of inspecting an underwater surface and of undertaking operations relating to the underwater surface following the inspection, the method comprising the steps of locating a submersible vehicle at an underwater surface which underwater surface is located in a body of water, inspecting the underwater surface using a first tool, providing a second tool on the submersible vehicle, the second tool being operable to perform an operation on the underwater surface, remotely activating the second tool and performing the operation of the second tool on the underwater surface

65 A method according to claim 64, wherein the inspection of the underwater surface by the first tool comprises imaging the underwater surface

66 A method according to claim 65, wherein the imaging comprises one or more of video image recording, ultrasonic thickness measurement scanning, acoustic resonance scanning, cathodic protection measurement

67 A method according to any one of claims 64 to 66, wherein the operation of the second tool is a cleaning operation

68 A method according to claim 67, wherein the operation of the second tool is cavitational cleaning

69 A method according to any one of claims 64 to 68, wherein a cavitational cleaning tool is provided on the submersible vehicle

70 A method according to claim 69, wherein the cavitational cleaning tool is operable to deliver a non-abrasive fluid to the underwater surface, which fluid is delivered from the tool at pressure

71 A method according to claim 70, wherein the fluid is delivered at pressures of between 1500 and 4000psι

72 A method according to any one of claims 64 to 71 , wherein the second tool is located at a fixed position relative to the underwater surface

73 A method according to claim 72, wherein the second tool is located at a fixed angle α and at a fixed distance, d, from the underwater surface and the fixed angle α is between 20 and 45 degrees and distance, d, is between 35mm and 80mm

74 A method according to any one of claims 64 to 73, wherein the steps of inspecting the underwater surface and of remotely activating the second tool are completed without the submersible vehicle being surfaced in the body of water

75. A method of cleaning an underwater surface comprising the steps: (a) locating a submersible apparatus at an underwater surface in a body of water; (b) providing a pressurised fluid and delivering the pressurised fluid through at least one nozzle configured to induce cavitation in the body of water;

(c) inducing cavitation in the body of water between the at least one nozzle and the underwater surface; (d) cleaning the underwater surface by way of cavitation.

76. A method according to claim 75, wherein the submersible apparatus is according to any one of claims 1 to 35.

77. A method according to claim 75, wherein the submersible apparatus is a submersible vehicle according to any one of claims 36 to 63.

78. A submersible vehicle substantially as hereinbefore described with reference to the Figures 5 to 11 of the accompanying figures.

79. A submersible apparatus substantially as hereinbefore described with reference to the Figures 1 to 4 of the accompanying figures.