WO2023242583A1

WO2023242583A1 - Inspection and/or maintenance method and associated apparatus

Info

Publication number: WO2023242583A1
Application number: PCT/GB2023/051576
Authority: WO
Inventors: Daniel CONSTANTINIS
Original assignee: E M & I (Maritime) Limited
Priority date: 2022-06-15
Filing date: 2023-06-15
Publication date: 2023-12-21

Abstract

Marine operational method of performing an operation from an enclosure. The enclosure has a marine working habitat. The method involves operating a Remotely Operated Vehicle (ROV) that is controllable or at least communicable via wired and/or wireless connection/s, such as to/from the enclosure. The method comprises operating the ROV from within the marine working habitat. The associated apparatus allows the electrical powering of the ROV via an electrical umbilical cable from the marine working habitat, with the ROV being powered via a step-down transformer powering the ROV from the vessel's power supply with a lower voltage than the vessel voltage.

Description

INSPECTION AND/OR MAINTENANCE METHOD AND ASSOCIATED APPARATUS

TECHNICAL FIELD

The present invention relates to a method of performing marine operations, such as inspecting and/or maintaining a marine vessel, installation or subsea equipment, or portion/s thereof; particularly, but not exclusively, operating auxiliary electrical equipment at least temporarily on or associated with a marine vessel; and associated apparatus.

BACKGROUND

Marine structures, such as floating offshore installations (FOIs) including oil drilling platforms and similar structures are generally intended for permanent or semipermanent deployment at a fixed location in the sea. Like ships, FOIs and also other wholly or partially submersible structures are critically dependent for safe operation on the pressure integrity of their hull or outer shell.

Marine vessels, such as ships, semi-submersibles, floating platforms, FOIs, FPSOs and the like, often require inspection and/or maintenance, such as for regulatory compliance.

Remotely-operated vehicles (ROVs) are often used with or instead of divers for performing underwater operations, such as hull inspections and/or operations, such as maintenance and repairs. The ROVs are typically remotely-controlled locally, with an operator on the structure being inspected or another nearby marine vessel.

Other marine operations may involve repairs whereby personnel may be required, such as hotwork. For example, repairs such as welding, electrical power tool use or the like, may be required to maintain a vessel. Such repairs may be performed internally and/or externally (e.g. to bulkheads, hulls, etc.). A temporary enclosure may be utilized so as to provide a working habitat for the performance of such operations.

It may be an object of one or more aspects, examples, embodiments, or claims of the present disclosure to at least mitigate or ameliorate one or more problems associated with the prior art. SUMMARY

According to aspects of the invention, there is provided a marine operational method; and associated apparatus.

The method may comprise performing an operation in an enclosure. The enclosure may comprise a marine working habitat. The marine working habitat may comprise a temporary marine working habitat, such as temporarily installable for the performance of a relatively short-term operation (e.g. in comparison to the lifespan of the marine vessel). The enclosure may be installed purely for the performance of an associated operation, such as an inspection and/or repair operation.

The method may comprise operating a Remotely Operated Vehicle. The method may comprise operation of the ROV by a person. Additionally, or alternatively, the ROV may be autonomous or semi-autonomous. The ROV may be selectively manually or autonomously operable. The ROV may be controllable or at least communicable via wired and/or wireless connection/s.

The method may comprise operating the ROV from within the marine working habitat.

The method may comprise electrically powering the ROV. The ROV may be electrically powered via a cable, such as an electrical umbilical. The method may comprise powering the ROV from the marine working habitat.

The method may comprise powering the ROV from a vessel’s power supply. The method may comprise powering the ROV indirectly from the vessel’s power supply. The method may comprise providing a step-down transformer for powering the ROV from the vessel’s power supply. For example, the ROV may be powered with a lower voltage than the vessel voltage, such as stepped down to (around) 230V from 400V available on the vessel. The method may comprise converting the phase. For example, the method may comprise converting the vessel’s 3-phase voltage to a single-phase voltage to allow powering of the ROV from the vessel’s power supply. The method may comprise filtering the voltage. For example, the method may comprise filtering the vessel’s voltage to provide a clean, or at least cleaner, voltage to the ROV. The method may comprise mitigating fluctuations and/or deficiencies in a vessel’s power supply, such as to ensure continuity of power to the ROV. Contrary to many vessel systems, it may be particularly advantageous to ensure continuity of power to the ROV. For example, provision of continuous power can help ensure safety and/or retention of the ROV. The method may comprise mitigating loss of power to the ROV. The method may comprise provision of continuous power to the ROV, even in an event of loss of vessel power.

Accordingly, rather than separately power the ROV, such as from a discrete power source (e.g. portable onto the vessel), the present method may provide a means of safely operating the ROV based on a vessel’s available power supply.

The method may comprise powering the ROV with an ‘Uninterrupted Power Solution’ (UPS) system. The ROV’s power supply may filter unstable power supplied by a vessel or other marine facility (which can adversely impact ROV performance). The method may comprise providing a suitable back-up power supply to safely retrieve the ROV in the event of power loss (of the vessel). The UPS may comprise an output power capacity of 6.0kWatts 16.0kVA. The ROV’s power supply may comprise a battery. The battery may be configured to provide a similar power as via the vessel’s supply (after step-down). In other examples, the battery may be configured to provide a different power. For example, in some embodiments, the battery may be of a lesser voltage, but still sufficient to power the ROV to retrieve the ROV. The method may comprise transforming the vessel power supply, such as with the step-down transformer for the ROV. The method may comprise supplying the UPS with the stepped-down voltage. The method may comprise powering the ROV from with the stepped-down vessel supply via the UPS. The battery may be charged (recharged) from the vessel supply (e.g. the stepped-down vessel supply).

The method may comprise providing additional power to the ROV than conventionally. For example, the method may comprise providing additional power to the ROV than conventionally available on a self-powered ROV or powered via a portable supply (e.g. as conventionally transported to the vessel with the ROV). The method may comprise providing the ROV with additional power to enable generation of additional thrust. More thrust will help the ‘supercharged’ ROVs cope with adverse weather conditions. More thrust may extend the upper limit of when it’s safe to deploy ROVs. The method may comprise providing a D/C to D/C Power Converter installed on the ROV. The method may comprise powering the ROV from one or more (e.g. at least two) PSUs at the topside. The method may comprise increasing the thrust of the ROV by at least 10%; by at least 20%; by at least 30%. The thrust increase may be in average thrust and/or in continuous pull. The thrust increase may be relative to thrust with fewer PSUs. For example, increasing the number of PSUs from one to two may provide an increase in thrust of at least 10%. The plurality of PSUs may be provided in parallel. The second PSU may be combined with a second DC to DC converter. Accordingly at least a pair of PSUs with respective DC to DC converters may be provided. The method may comprise adding or retrofitting a second PSU and/or second DC to DC converter to or alongside a first PSU and/or second DC to DC converter. The method may comprise providing cabling to connect at least two PSUs together to the ROV. The method may comprise providing or adding a boost converter. The DC to DC converter/s may step down from the 600 volts delivered by the (twin or more) PSU (while stepping up the current) from its input (supply) to its output (load). Accordingly, the method may comprise providing more amps to the thrusters. Accordingly, the thrusters may provide increased total thrust.

The method may comprise providing the Uninterruptible Power Supply (UPS) system. The UPS system may comprise one or more of: UPS; marine filter; battery pack. The UPS system may be configured to provide a stabilized power supply to ROV. The UPS system may be configured to prevent or at least mitigate inconsistent power supplies to the ROV, which could otherwise cause reliability issues and reduced performance. The method may comprise providing emergency power when an input power source fails. For example, the method may comprise providing power to the ROV using the same supply lines & source (e.g. UPS) in an even of power failure from the vessel. For example, in an absence of power from the vessel (e.g. from the FPSO’s power), the UPS system may be configured to enable ROV recovery; and optionally re-deployment ( e.g. once power has been restored). This safety provision of the present disclosure may be especially important when the ROV is operating in a potentially hazardous location at the point of power loss.

The method may comprise increasing the uptime for ROV operations. The method may comprise increasing the uptime for ROV operations in circumstances (e.g. water currents) which are usually restrictive to standard equipment set-ups.

The method may comprise powering the ROV from a controlled environment, such as via the enclosure described herein. The method may comprise powering and/or controlling and/or operating the ROV from a de-humidified habitat to prevent moisture ingress to the ROV topside control and power systems due to humidity. The enclosure may comprise an over-pressurized safe working habitat. The enclosure may comprise a main habitat The main habitat may be for housing personnel and/or hardware. In at least some examples, the enclosure may comprise a secondary habitat. The secondary habitat may be smaller than the main habitat. The secondary habitat may be provided as an optional additional habitat. The secondary habitat may be for use with specialist hardware, such as cavitation pumps, whereby a discrete additional habitat may be particularly beneficial. Over-pressurization in the habitat/s of the enclosure may be achieved by delivering a flow of air, such as by one or more venturi air movers connected to an air supply. Manometers may be used to monitor air pressure from within and outside the habitat/s, such as to ensure pressure regulation. Accordingly, the over-pressurization may be adjusted, such as automatically (e.g. by adjusting air supply). The enclosure may comprise one or more monitors, such as a gas monitor/s. The monitor/s may be disposed inside and/or outside the enclosure. The monitor/s may provide an early warning of any hydrocarbons in the atmosphere, such as to allow safe shutdown of any electrical items.

The enclosure may comprise a humidity monitor. The enclosure may comprise a humidity regulator. The enclosure may comprise a dehumidifier. Accordingly, the method may comprise controlling a humidity of the atmosphere within the enclosure. The humidity may be controlled so as to improve safety. For example, the humidity may be controlled to remain below a threshold, such as a predetermined threshold. The predetermined threshold may correspond to a humidity below which safety is improved, such as by mitigating ignition risk. The dehumidifier may comprise a capacity of at least 10 liters per day; for example, up to 50 liters per day; 30°C 80%RH. The enclosure may be configured to comprise a regulated RH index.

Hotwork can be an important activity on operating assets but it can raise serious safety issues if not managed properly. The present disclosure provides a means of significantly enhancing the safety of hotwork in hazardous areas. The present disclosure provides a means of significantly enhancing the safety of hotwork in hazardous areas by providing a controlled and comfortable working environment for various tasks. The present disclosure provides a safer, more flexible and more cost effective than traditional habitats. The present disclosure may also release more bed spaces for other priority work. For example, the present disclosure may enable performance of one or more marine operations whereby a reduced number of personnel is required on board an offshore vessel.

The present disclosure may provide an enclosure with a controlled atmosphere of overpressurized air at or below a predetermined humidity. The overpressurization and/or humidity may be absolute. Alternatively, the overpressurization and/or humidity may be relative to the pressure and/or humidity external to the enclosure.

The enclosure may be installable in a variety of orientations. For example, the enclosure may be installable in one or more vertical orientations and/or one or more horizontal orientations and/or an inclination therebetween. The enclosure may be installable in any orientation. The enclosure may be customised to in a wide variety of shapes and sizes to suit any application. The enclosure may be compliant with ATEX industry standards.

The enclosure may provide enhanced safety. The enclosure may be configured to monitors safe condition, such as constantly monitor conditions for safety. The enclosure may be configured to monitor all critical habitat parameters. The enclosure may be configured to monitor one or more of: flammable gas, oxygen levels, pressure, humidity, temperature. The enclosure may be configured to automatically For example, the enclosure may be configured to trigger automatic shutdown and/or evacuation procedures.

The invention may be concerned with the provision of a clean air zone in the form of a habitat within which so-called "hot work" may be carried out. Hot work may be deemed to be any activity which has the potential to introduce a source of ignition into a zone which may contain a gas and air mixture within a flammable range. The lower limit of such a range may be defined as the concentration below which there is insufficient flammable gas to support combustion and the upper limit may be the concentration above which there is insufficient air to support combustion. Such work is often carried out in vessels adapted to contain gas or flammable liquids such as the oil storage tanks of crude oil carriers. It is sometimes necessary, to carry out, when such vessels are empty, repair work on parts of the internal structure. This work may involve welding or cutting, and residues of gas and oil can cause an explosion when a source of ignition is introduced into such a potentially hazardous environment. The working enclosure may be adapted to provide a clean air zone within a potentially hazardous environment, the enclosure comprising a canopy adapted to cover at least a part of a working surface to define therewith a clean air zone, at least one inlet duct connecting said zone to a supply of clean air, means to monitor the content of the air supplied to said zone, and alarm/shut down means responsive to the monitoring means.

The term "clean air" is to be construed as including either fresh clean air which is free of acutely inflammable gases, or for example, a mixture of clean air and an inert gas.

According to the present disclosure such a working enclosure is improved by the provision of means to discharge air from the enclosure to establish a controlled operating air pressure within the enclosure.

The discharge means may be a duct having a diameter less than that of the clean air inlet duct. The operating air pressure within the enclosure may be controlled within the range of 0.1 to 0.3 bar above ambient pressure outside the canopy.

An air lock may be provided in the canopy wall to enable operator access without substantially affecting the operating air pressure within the canopy.

Means may be provided to direct air circulation around the interior of the canopy thus to ensure substantially complete scavenging of any contaminant gases therefrom.

The canopy may be provided in the form of a flexible shroud or a rigid enclosure or bubble. Preferably, the canopy also includes means whereby the edges of the canopy may be maintained in close relationship with the working surface.

The method may comprise ROV operations at a depth of 50m. In at least some examples, the method may comprise ROV operations at depths in excess of 50m.

The method may comprise a ROV operation, such as in an inspection and/or maintenance of a hull and/or underwater opening, such as that described in GB patent application GB2118909.7 and International Patent Application PCT/GB2022/053373, the contents of which are hereby incorporated herein. The method may comprise inspection and/or maintenance of a marine vessel, installation or subsea equipment, such as a hull opening (e.g. to repair or replace sea chest isolation valves), without divers.

According to a further aspect, there is provided an apparatus for performing a marine operational method, such as any of the methods described herein. The apparatus may comprise an enclosure. The enclosure may comprise a marine working habitat. The apparatus may comprise a ROV. The ROV may be controllable or at least communicable via wired and/or wireless connection/s, such as to/from the enclosure. The apparatus may be configured to operate the ROV from within the marine working habitat. The apparatus may comprise a step-down transformer. The step-down transformer may be configured to step-down the vessel’s power supply to power the ROV from the vessel’s power supply with a lower voltage than the vessel voltage. The apparatus may comprise an electrical umbilical cable. The apparatus may comprise an electrical umbilical cable. The apparatus may comprise the electrical umbilical cable extending from the marine working habitat, to power the ROV from the vessel’s power supply via the step-down transformer powering.

Accordingly, in at least one example, there is provided an apparatus for performing the marine operational method of any preceding claim, the apparatus comprising at least: the enclosure; the step-down transformer for powering the ROV from the vessel’s power supply with a lower voltage than the vessel voltage; the electrical umbilical cable for powering the ROV from the enclosure’s marine working habitat; and the ROV, the ROV being configured to be operated from the enclosure via the electrical umbilical cable from the vessel’s power supply.

The ROV may comprise a plurality of buoyancy elements, such as one or more of: zones, regions, relatively buoyant members, pockets, chambers or the like. The buoyancy elements may be distributed. The ROV may comprise at least one buoyancy element above the ROV’s centre of gravity. Additionally, the ROV may comprise at least one buoyancy element below the ROV’s centre of gravity. In at least some examples, the ROV comprises buoyancy elements above and below the centre of gravity, whereby the buoyancy provided by the lower buoyancy element/s, below the centre of gravity, at the bottom of the ROV provide a similar total buoyancy to the total buoyancy provided by the upper buoyancy element/s, above the centre of gravity, at the top of the ROV. The ROV’s buoyancy may be configured to facilitate movement associated with the thrusters in any direction, irrespective of orientation/angle of the ROV. The ROV may be configured, such as with the particular arrangement of buoyancy elements above and below the CoG, to enable application of thurst in any direction without necessarily resulting in rotational motion of the ROV. The method may comprise applying or providing thrust in any direction without undesirably applying a rotation moment to the ROV.

In contrast to convention inspection class ROVs, providing buoyancy below the centre of gravity can enable maintenance of alignment of upwards buoyancy and downward gravity forces. Accordingly, the ROV may be configured to adopt an angled position, such as an angled pitch and/or roll position, whereby the angled position can be passively maintained. For example, the ROV may be configured to maintain a selected one of a plurality of angled positions. The ROV may comprise aligned forces or vectors of gravity and buoyancy. The ROV may comprise aligned forces or vectors of gravity and buoyancy irrespective of orientation of the ROV. The ROV may comprise aligned forces or vectors of gravity and buoyancy irrespective of orientation of the ROV.

The ROV may be equipped with six degrees of freedom of movement. The ROV may be configured to move in any linear direction (e.g. x, y or z - or any combination thereof). Additionally, or alternatively, the ROV may be configured to move rotationally about any axis (e.g. about x, y or z - or any combination thereof, such as an intermediate or imaginary axis).

The ROV may be configured to move in any horizontal direction. For example, the ROV may be configured to move in any forward, rearward, sideward direction, or any intermediate direction - irrespective of which direction ROV is ‘facing’. Additionally, or alternatively, the ROV may be configured to move in any vertical direction. For example, the ROV may be configured to move in any upward, downward, inclined direction, or any intermediate direction - irrespective of which direction ROV is ‘facing’. The ROV may be configured to move in any horizontal and/or vertical direction with a same or similar amount of thrust, such as maximum thrust. The ROV may be configured to move in any direction with a similar maximum thrust, irrespective of orientation of the ROV (e.g. in which direction ROV is ‘facing’). The ROV may comprise a plurality of thrusters. The plurality of thrusters may be arranged around or about the ROV’s centre of gravity and/or the buoyancy element/s such that the thrusters can always impart a net vector thrust through the ROV’s centre of gravity. The ROV may be configured to exert thrust such that the ROV is always propelled with a maintained orientation. The ROV may be configured to exert thrust such that the ROV is always propelled with a maintained orientation, irrespective of orientation of the ROV (e.g. angle of pitch and/or roll), relative to direction of thrust.

The ROV may be configured to approch a portion/s of the vessel or the intended inspection/maintenance object/target at any angle of the ROV. For example, the ROV may be tilted to match or mirror an inclination of the obkect/target. Additionally, or alternatively, the ROV may be angled to direct a particular portion of the ROV towards the object/target at a particular angle. The ROV may be configured to be moved in a direction unrelated to the angle. For example, the ROV may be configured to move along a path (linear or otherwise) whilst maintaining the angle, the path being different, even independent, of the angle. The path may be lateral, such as transverse or perpendicular, to the path. For example, the ROV may be angled towards an object, such as a sloped or curved hull or chain or rope or the lie; and configured to follow a path alon the hull/chain/rope, etc., whilst mainting the same angle. The angle may be absolute, such as relative to the vertical. Additionally, or alternatively, the angle may be relative, such as relative to the path and/or object. For example, where the path follows a non-linear portion of hull/cable/rope etc., then the ROV may rotate to mainatain a same angle relative to the path and/or object. The method may comprise measurement of an angle. For example, the method may comprise rolling the ROV (e.g. through 360°) and generating a horizontal line (e.g. on a monitoring screen) and measurement/derviation of the mooring angle thereby. This provides significant advantages over a a conventional ROV without the configuration of the present ROV (e.g. without such pitch control) that can only approch horizontally and needs to use a tool that is placed on the mooring system to measure the mooring system angle. Accordingly, the method may comprise a more efficent cleaning, inspection and/or measuring of vessels or associated apparatus, such as mooring systems or the like.

The ROV may be equipped with one or more of: a visual camera; a sonar camera or scanner; an inspection instrument/s; a repair tool/s; an ultrasonic measurement device; a laser scanner; a sampling tool. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will readily be appreciated that features recited as optional with respect to the first aspect may be additionally applicable with respect to the other aspects without the need to explicitly and unnecessarily list those various combinations and permutations here (e.g. the apparatus or device of one aspect may comprise features of any other aspect).

Optional features as recited in respect of a method may be additionally applicable to an apparatus or device; and vice versa.

In addition, corresponding means for performing one or more of the discussed functions are also within the present disclosure.

The above summary is intended to be merely exemplary and non-limiting. Various respective aspects and features of the present disclosure are defined in the appended claims.

It may be an aim of certain embodiments of the present disclosure to solve, mitigate or obviate, at least partly, at least one of the problems and/or disadvantages associated with the prior art. Certain embodiments may aim to provide at least one of the advantages described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 shows a schematic view of a working enclosure; Figure 2 shows a perspective view of a ROV;

Figure 3 shows a perspective view of the ROV of Figure 2 during deployment;

Figure 4 shows a method according to the present disclosure;

Figure 5 shows a schematic depiction of a traditional ROV;

Figure 6 shows a schematic depiction of a ROV according to the present disclosure; Figure 7 shows an example of a ROV according to the present disclosure, in a first use; and

Figure 8 shows an example of a ROV according to the present disclosure, in a second use.

DETAILED DESCRIPTION

Fig. 1 is a perspective view of a working enclosure 40 and occupied by an operator in readiness to carry outwork on a vertical surface within, for example, an emptied oil tank.

The canopy 10 made from, for example, a durable material such as nylon, pre-treated or lined with a fire prevention substance or blanket, is supported by a frame 11 and has a peripheral skirt 12 adapted to locate closely against a working surface to which the device may be applied and retained by magnetic pads 13. The canopy is supported from above by rigging ropes 14 and 15. A sealable access flap 16 is provided through which an operator 17 may enter and leave the enclosure. One or more suspension lines 18 to support the operator, pass into the canopy 10 through a generally sealed aperture 19 at the top of the canopy. Thus the enclosure can be located temporarily in a fixed position against the working surface and in substantially sealed engagement therewith by means of the skirt 12, the flap 16 and the aperture 19.

An air inlet duct 20 is connected to the canopy wall and communicates with the interior of the enclosure. The duct is preferably made from a flexible material and passes upwardly out of the hazardous environment, for example, through an aperture in a decking panel 21 and is supported above same by a frame 22 at the upper open end of which there is provided a fan 23 supplying air through the duct 20 into the enclosure. The fan 23 is associated with a sensing or monitoring device (not shown) which is further associated with an adjacent or remote alarm I shut down system for a purpose to be described. Within an enclosure as described the operator may carry out welding, cutting or similar operations without the risk of causing an explosion since clean air is ducted into the enclosure at a slight over-pressure thus bleeding from the flap 16 and aperture 19, and around the skirt 12.

The upstanding frame 22 ensures that the fan supplying clean air is disposed well above the deck 21 and any low-lying gases which may be present.

The sensing or monitoring device associated with the fan 23 is adapted to detect the presence of a toxic or inflammable contaminant in the air being supplied to the enclosure, and if present will either sound an alarm to alert the operator or other staff thus to discontinue the hot work, or to shut down the supply of power to whatever hot work tools are being used in the enclosure, or simply to shut down the fan supplying the contaminated air to the duct 20.

When the working surface upon which the hot work is being carried out is located between two potentially hazardous zones, for example, when repairing a bulkhead separating two hydro-carbon storage tanks, a second enclosure similar to that described may be positioned on the opposite side of the bulkhead whereat local heating of the working surface may otherwise create an explosive condition.

Although not explicitly shown, the canopy 10 houses a dehumidifier and a humidity monitor. Accordingly, the atmosphere within the canopy 10 is also of controlled humidity, as well as controlled overpressurization. The humidity can be selectively programmed to remain at (or below) a predetermined threshold. Accordingly, the canopy 10 provides a safer working environment for performing marine operations, such as hotwork, inspections, ROV operations (e.g. power and/or control) or the like.

Referring now to Figure 2, there is shown a ROV 50 according to the present disclosure. The ROV 50 is configurable to comprise inspection and/or maintenance apparatus, such as one or more of: lighting, cameras, scanners, manipulators. The ROV is self-propelling, with electrical motors powering directionally-controllable propulsion means 52. As shown in Figure 2, the ROV can be electrically powered via a cable or umbilical 54. The ROV 50 is shown in Figure 3 suspended from a hoist or winch, but it will be appreciated that when released, the ROV 50 is free to vary depth and position by virtue of the propulsion means 52. Typically, the ROV 50 is remotely controlled, with the operator providing input to the ROV 50, often in response to information relayed to the operator (e.g. images from the ROV’s camera/s). In at least some examples, the cable 54 transfers electrical power to the ROV from a canopy, such as that 10 shown in Figure 1. Accordingly, the ROV power supply can be housed in a safe marine habitat. It will be appreciated that the cable 54 shown can be powered from a vessel’s power supply via a UPS, marine filter and a step-down transformer. Accordingly, the ROV 50 may receive more power than conventionally, such as when self-powered or powered from a portable power supply taken onto the vessel along with the ROV. Accordingly, the ROV 50 may be able to provide more thrust. More thrust can help the ‘supercharged’ ROV 50 cope with adverse weather conditions. Likewise, the enhanced power supply may enable an extension of the upper limit of when it’s safe to deploy ROVs. In at least some examples, the ROV may be powered using two ‘Power Supply Units’ (PSUs) connected in series at the topside unit, and a D/C to D/C Power Converter installed on the ROV. In at least some examples, the ROV may be provided with a thrust increase of 35% on average; and an increase of 33% average on continuous pull.

Figure 4 shows a method 2 according to the present disclosure. A first step 4 involves connecting a ROV 50 to vessel power supply via step-down transformer and umbilical 54. A second step 6 involves operating the ROV 50, such as from a marine working habitat 40. A third step 8 comprises performing a marine operation, with the ROV 50.

Figure 5 shows a schematic depiction of a traditional Inspection Class ROV. Here, it can be seen that the ROV’s comprises an unbalanced or misaligned buoyancy, relative to the centre of gravity, at least when the ROV 50 is oriented at a different angle (e.g. pitch and/or roll) as shown in Figure 5b, relative to a neutral or default orientation, such as shown in Figure 5a.

Figure 6 shows a schematic depiction of a ROV 50 according to the present disclosure. The ROV 50 comprises a plurality of buoyancy elements 51 , such as one or more of: zones, regions, relatively buoyant members, pockets, chambers or the like. The buoyancy elements 51 are distributed. The ROV 50 comprises at least one buoyancy element 51 above the ROV 50’s centre of gravity 53. Additionally, the ROV 50 comprises at least one buoyancy element 51 below the ROV 50’s centre of gravity 53. Here, the ROV 50 comprises buoyancy elements 51 above and below the centre of gravity, whereby the buoyancy provided by the lower buoyancy element/s 51 , below the centre of gravity 53, at the bottom of the ROV 50 provide a similar total buoyancy to the total buoyancy provided by the upper buoyancy element/s 51 , above the centre of gravity 53, at the top of the ROV 50. The ROV 50’s buoyancy is/are configured to facilitate movement associated with the thrusters 52 in any direction, irrespective of orientation/angle of the ROV 50. The ROV 50 is configured, such as with the particular arrangement of buoyancy elements 51 above and below the CoG 53, to enable application of thrust in any direction without necessarily resulting in rotational motion of the ROV 50. The method comprises applying or providing thrust in any direction without undesirably applying a rotation moment to the ROV 50.

In contrast to conventional inspection class ROV 50s (see e.g. Figure 5), providing buoyancy below the centre of gravity 53 can enable maintenance of alignment of upwards buoyancy and downward gravity forces, as shown in Figures 6a and 6b. Accordingly, the ROV 50 is configured to adopt an angled position, such as an angled pitch and/or roll position (see e.g. Figure 6b), whereby the angled position can be passively maintained. For example, the ROV 50 her in Figure 6b is configured to maintain a selected one of a plurality of angled positions. The ROV 50 comprises aligned forces or vectors of gravity and buoyancy. The ROV 50 comprises aligned forces or vectors of gravity 55 and buoyancy 57 irrespective of orientation of the ROV 50. The ROV 50 comprises aligned forces or vectors of gravity and buoyancy 55, 57 irrespective of orientation of the ROV 50.

The ROV 50 is equipped with six degrees of freedom of movement. The ROV 50 is configured to move in any linear direction (e.g. x, y or z - or any combination thereof). Here, the ROV 50 is configured to move rotationally about any axis (e.g. about x, y or z - or any combination thereof, such as an intermediate or imaginary axis).

The ROV 50 is configured to move in any horizontal direction. For example, the ROV 50 is configured to move in any forward, rearward, sideward direction, or any intermediate direction - irrespective of which direction ROV 50 is ‘facing’. Here, the ROV 50 is configured to move in any vertical direction. For example, the ROV 50 is configured to move in any upward, downward, inclined direction, or any intermediate direction - irrespective of which direction ROV 50 is ‘facing’. The ROV 50 is configured to move in any horizontal and/or vertical direction with a same or similar amount of thrust, such as maximum thrust. The ROV 50 is configured to move in any direction with a similar maximum thrust, irrespective of orientation of the ROV 50 (e.g. in which direction ROV 50 is ‘facing’).

Figure 7 shows an example of the ROV 50 according to the present disclosure, in a first use. The ROV 50 comprises a plurality of thrusters 52. The plurality of thrusters 52 are arranged around or about the ROV 50’s centre of gravity 53 and/or the buoyancy element/s 51 such that the thrusters 52 can always impart a net vector thrust through the ROV 50’s centre of gravity 53. Here, there are 8 thrusters 52: one at or towards each corner of the cuboid ROV 50. The ROV 50 is configured to exert thrust such that the ROV 50 is always propelled with a maintained orientation, irrespective of orientation of the ROV 50 (e.g. angle of pitch and/or roll), relative to direction of thrust. The angle can be absolute, such as relative to the vertical. As shown here, the angle can be relative, such as relative to the path 90 and/or object 80. For example, where the path 90 follows a non-linear portion of hull 80 such as in Figure 7, from underneath the hull 80 to a seachest 82 opening at the side, then the ROV 50 may rotate to mainatain a same angle relative to the path 90 and object 80. This provides significant advantages over a a conventional ROV 50 without the configuration of the present ROV 50 (e.g. without such pitch control) that can only approch horizontally.

Accordingly, the method comprises a more efficent cleaning, inspection and/or measuring of vessels or associated apparatus, such as mooring systems or the like.

Figure 8 shows an example of the ROV 50 according to the present disclosure, in a second use. The ROV 50 is configured to approch a portion/s of the vessel or the intended inspection/maintenance object/target at any angle of the ROV 50. For example, the ROV 50 is tilted to match or mirror an inclination of the obkect/target. As shown in Figure 8, the ROV 50 is angled to direct a particular portion of the ROV 50 towards the object/target at a particular angle. Here, the ROV 50 is configured to move along a path (linear or otherwise) whilst maintaining the angle, the path being different, even independent, of the angle. The path can be lateral, such as transverse or perpendicular, to the path. For example, in Figure 8 the ROV 50 is angled towards the cable 80; and configured to follow a path around the chain 80 (e.g. between the two positions of the single ROV 50 shown in Figure 8) whilst mainting the same angle. Accordingly a camera/s and/or scanner/s can be continuously directed towards the chain 80 whilst performing a complete (e.g. circumferentially complete) inspection of the chain 80. It will be appreciated that the ROV 50 is equipped with one or more of: a visual camera; a sonar camera or scanner; an inspection instrument/s; a repair tool/s; an ultrasonic measurement device; a laser scanner; a sampling tool.

It will also be appreciated that the ROV 50 here forms part of an apparatus 100, such as together with the enclosure 40 of Figure 1. Here, the ROV 50 is controllable or at least communicable via wired and/or wireless connection/s, such as to/from the enclosure 40. The apparatus 100 is configured to operate the ROV 50 from within the marine working habitat. The apparatus comprises a step-down transformer (e.g. within the enclosure 40), which is configured to step-down the vessel’s power supply to power the ROV 50 from the vessel’s power supply with a lower voltage than the vessel voltage. The apparatus 100 comprises an electrical umbilical cable 54, such as extending from the marine working habitat 40, to power the ROV 50 from the vessel’s power supply via the step-down transformer.

It will be appreciated that the umbilical cable 54 and other portions of the apparatus 100 are not shown in all figures for clarity and ease of viewing. Nonetheless, it will be appreciated that the umbilical 54 can extend from the enclosure 40 to the ROV 50. Benefits of one or more of the examples or embodiments described herein can include one or more of: Enhanced Safety; Reduced Cost; Reduced POB; Improved Budget Certainty (e.g. lower weather dependency).

Accordingly, the present disclosure here relates to diverless methods, including those disclosed in WO/2020/161479, the contents of which are incorporated herein by reference. It is accordingly an object of at least some examples of this disclosure to inspect and/or maintain a marine vessel, installation or subsea equipment, such as a hull opening (e.g. to repair or replace sea chest isolation valves), without divers.

It will be appreciated that at least some of these processes may be at least computer- assisted. It will be appreciated that embodiments of the present invention can be realised in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program comprising code for implementing a system or method as disclosed in any aspect, example, claim or embodiment of this disclosure, and a machine-readable storage storing such a program. Still further, embodiments of the present disclosure may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The applicant indicates that aspects of the present disclosure may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the disclosure. For example, it will be appreciated that although described here for a single device, multiple devices, such as a plurality of ROVs, may be provided (e.g. powered, such as simultaneously powered, from a vessel’s power supply).

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

Claims

1. A marine operational method of performing an operation from an enclosure, the enclosure comprising a marine working habitat, the method comprising operating a Remotely Operated Vehicle, the ROV being controllable or at least communicable via wired and/or wireless connection/s, such as to/from the enclosure, the method comprising operating the ROV from within the marine working habitat; wherein the method comprises electrically powering the ROV via an electrical umbilical cable from the marine working habitat, with the ROV being powered from a vessel’s power supply via a step-down transformer powering the ROV from the vessel’s power supply with a lower voltage than the vessel voltage.

2. The method of claim 1 , wherein the method comprises powering the ROV with an ‘Uninterrupted Power Solution’ (UPS) system.

3. The method of claim 2, wherein the UPS comprises an output power capacity of 6.0kWatts I .QW .

4. The method of any preceding claim, wherein the method comprises powering the ROV from one or more (e.g. at least two) Power Supply Units (PSUs) at the topside.

5. The method of any preceding claim wherein the voltage is stepped down to around 230V from 400V available on the vessel.

6. The method of any preceding claim, wherein the method comprises converting the vessel’s 3-phase voltage to a single-phase voltage to power the ROV from the vessel’s power supply.

7. The method of any preceding claim, wherein the method comprises mitigating fluctuations and/or deficiencies in a vessel’s power supply to ensure continuity of power to the ROV, including mitigating loss of power to the ROV by provision of continuous power to the ROV even in an event of loss of vessel power.

8. The method of any preceding claim, wherein the method comprises not separately powering the ROV primarily from a discrete power source, such as a portable power supply brought onto the vessel, the ROV being safely based on a vessel’s available power supply.

9. The method of any preceding claim, wherein the ROV’s power supply filters power supplied by the vessel; and providing a suitable back-up power supply to safely retrieve the ROV in the event of power loss (of the vessel).

10. The method of any preceding claim, wherein the ROV’s power supply includes a battery; wherein the battery is configured to provide a similar power as via the vessel’s supply after step-down. In other examples, the battery may be configured to provide a different power.

11. The method of any preceding claim, wherein the method comprises providing additional power to the ROV than conventionally, including providing additional power to the ROV than conventionally available on a self-powered ROV or powered via a portable supply.

12. The method of claim 11 , wherein the additional power increases the thrust of the ROV by at least 10%; by at least 20%; by at least 30%.

13. The method of any preceding claim, wherein the method comprises providing a D/C to D/C Power Converter installed on the ROV.

14. The method of any preceding claim, wherein the method comprises powering the ROV from the marine working habitat, the marine working habitat comprising a dehumidified habitat to prevent moisture ingress to the ROV topside control and power systems due to humidity.

15. The method of claim 14, wherein the habitat comprises an over-pressurized safe working habitat for housing personnel and/or hardware.

16. The method of claim 14 or 15, wherein the habitat comprises a temporary marine working habitat, such as temporarily installable for the performance of a relatively short-term operation (e.g. in comparison to the lifespan of the marine vessel).

17. The method of any preceding claim, wherein the method comprises performing the operation on or to the vessel, the vessel being the marine vessel powering the ROV; wherein the marine vessel is selected from one or more of: ships, semisubmersibles, floating platforms, FOIs, FPSOs or other marine facility.

18. The method of any preceding claim, wherein the method comprises ROV operations at a depth of 50m or more; and includes an inspection and/or maintenance of a hull and/or underwater opening.

19. The method of any preceding claim, wherein the operation comprises hotwork, particularly in hazardous areas.

20. An apparatus for performing the marine operational method of any preceding claim, the apparatus comprising at least: the enclosure; the step-down transformer for powering the ROV from the vessel’s power supply with a lower voltage than the vessel voltage; the electrical umbilical cable for powering the ROV from the enclosure’s marine working habitat; and the ROV, the ROV being configured to be operated from the enclosure via the electrical umbilical cable from the vessel’s power supply.