A first aspect of the invention relates, more particularly, to submarine sensing systems, such as seafloor seismic exploration systems.

There are currently two principle seafloor seismic exploration systems. A first system employs hydrophones that each comprise a crystal that is compressed by sound waves to generate a voltage signal. A second system employs geophones (typically in combination with hydrophones) that each comprise a magnet which is movable within a coil to generate a voltage. The voltages are then interpreted to build-up a picture of the submarine structure of the earth in the test location.

In the first system, a vessel tows a number of streamers (typically between 6 and 20, each of six kilometres or more in length) each containing a plurality of hydrophones. The hydrophones record reflected sound waves generated by a pneumatic source, for example, which is towed either behind the same vessel or behind another following vessel. The source generates sound waves that travel through the water medium and are reflected by boundaries between different rock formations below the seabed. By recording the reflected soundwaves, it is possible to build a diagrammatic representation of the structure of the earth beneath the seabed, and to locate oil traps, reservoirs or formations that are likely to contain such traps or reservoirs.

Although this arrangement has been successfully commercially employed for many years, it exhibits a number of serious disadvantages. The chief disadvantage is that this arrangement does not permit the recording of shear waves, as these waves are not transmitted through the water medium. The recording of shear waves is particularly desirable as a means for further determining rock properties, that determination not being particularly successful with P or compressional waves alone.

A further disadvantage is that this system is particularly susceptible to noise, such as submarine noise or noise generated at the surface of the sea during stormy weather, for example. Furthermore, the vessels towing the streamers are very difficult to control as they cannot easily stop and must undertake long, time-consuming turns to reduce the likelihood of the deployed streamers becoming tangled. A further disadvantage is that sophisticated tracking and positioning equipment is required to

determine the exact location, in real time, of each of the hydrophones on the streamers.

To alleviate these problems, the second system-known in the art as OBS (Ocean Bottom Seismic)-was developed. OBS involves the placing of a large number of geophones, usually in combination with hydrophones, on the seabed. The geophones and hydrophones are typically deployed in pairs at locations spaced 50m apart along linear arrays that can be as much as twelve kilometres in length. A plurality of arrays are deployed and are connected to a stationary recording vessel which records signals from the'phones and supplies power thereto.

Whilst the OBS system alleviates some of the problems associated with the first system, it also exhibits a number of serious disadvantages. The chief disadvantage associated with the OBS system is cost. In order for the system to be operated effectively, it typically must employ a minimum of four separate vessels-a first pair to deploy the arrays, a third to carry and operate the signal generating equipment and a fourth, stationary, vessel for recording signals from the arrays. The fourth recording vessel is connected to the arrays by jumpers which are extremely vulnerable to breakage, and thus it is essential for the recording vessel to be kept in the same position at all times when connected to the arrays. A further problem is that the repeated deployment and storage of the arrays can cause the cables to be broken or frayed, thereby increasing the amount of maintenance required to keep the system operational.

It is apparent therefore that a need exists for a system that alleviates some or all of the problems associated with the above mentioned systems. Accordingly, it is an aim of the present invention to provide just such a system.

-In accordance with this first aspect of the invention, there is provided a submarine exploration system comprising: at least one submarine assembly having at least one signal detector; and a buoy connected to said submarine assembly, said buoy having wireless communications means for transmitting said detected signals.

Preferably, the system comprises a remote station for receiving said transmitted detected signals and/or signal generating means. Preferably, the signal generating means is mounted on a vessel which is capable of deploying said buoy and said submarine assembly. Alternatively, the signal generating means may be mounted on a separate vessel to that which is capable of deploying said buoy and said submarine

assembly.

Preferably, the submarine assembly comprises at least one hydrophone and/or at least one geophone. More preferably, the submarine assembly comprises three geophones.

Most preferably, the submarine assembly comprises an elongate mounting arm and a first of said geophones is mounted in parallel to said arm, a second of said geophones is mounted substantially perpendicularly to said arm, and a third of said geophones is mounted at right angles to said first and second geophones. This arrangement enables shear waves to be detected.

Preferably, said submarine assembly also comprises three hydrophones mounted at spaced locations on said arm Preferably, said submarine assembly comprises means for indicating the location of the assembly. The indicating means may further indicate the alignment of the assembly. The indicating means may comprise a pair or transponders mounted on said assembly at spaced locations from one another.

Preferably, the buoy comprises an impact resistant housing having an internal cavity sealed against water ingress ; power means for powering said wireless communications means; and an antenna by means of which said signals are transmitted to said remote station.

Preferably, the buoy comprises float means for maintaining the buoyancy of the buoy. Preferably, the wireless communications means comprises a UHF radio transmitter and/or the power means comprises one or more batteries and/or the power means comprises one or more solar cells forming an integral part of the housing.

Preferably, the solar cells form at least part of a lid that is capable of closing the internal cavity of the housing. The antenna may be mounted on the buoy via a spring loaded mounting.

Preferably, the underside of the buoy is provided with an eyelet to which a kelum grip may be attached. Preferably, the impact resistant housing is of tough ABS plastic. Preferably, the float means comprises closed cell polyurethane foam. The float means may be integrally formed with the housing.

Preferably, the system comprises a submarine cable attached at one end to said transmitting means and at the other end to the submarine assembly, the signals detected

by said detecting means being passed to said transmitting means for transmission.

The wireless communications means may comprise a receiver for receiving signals transmitted from said remote station. The receiver may be a UHF receiver.

Preferably, the submarine assembly is installed, in use, on the seabed and/or the buoy is capable of floating on or near the surface.

In accordance with the first aspect of the invention, there is also provided a method of submarine exploration comprising: deploying at least one submarine assembly connected to a buoy; detecting signals with one or more signal detectors provided on said submarine assembly; and transmitting said detected signals from said buoy with wireless communications means provided within said buoy.

A second aspect of the invention relates to marine buoys, and more particularly to buoys that are suitable for use with the above mentioned exploration system.

A large number of different types of buoys have previously been proposed.

However, none of these buoys are suitable for use with the above mentioned exploration system, nor are they generally suitable for use in the extreme conditions often encountered during marine exploration.

If buoys are to be deployed during marine exploration, then these buoys should be extremely hardy and capable of withstanding rough weather. They should also be able to withstand collisions with shipping without adversely affecting the operating capacity of the buoy. Furthermore, they should be relatively maintenance free as they are typically deployed far from shore and thus cannot easily be returned to shore, or on-board ship, for maintenance.

In accordance with this second aspect of the invention, there is provided a buoy for a submarine exploration system, the buoy comprising: an impact resistant housing having an internal cavity sealed against water ingress; wireless transmitting means provided within said housing for wireless transmission of signals to a remote station; power means for powering said transmitter; and an antenna by means of which said signals are transmitted to said remote station.

Preferably, the buoy comprises float means for maintaining the buoyancy of the buoy. Preferably, the transmitting means comprises a UHF radio transmitter.

Preferably, the power means comprises one or more batteries. Preferably, the power means also comprises one or more solar cells forming an integral part of the

housing. Preferably, the solar cells form at least part of a lid that is capable of closing the internal cavity of the housing.

The antenna is preferably mounted on the buoy via a spring loaded mounting.

Preferably, the underside of the buoy is provided with an eyelet to which a kelum grip may be attached.

The impact resistant housing may be of tough ABS plastic. The float means may comprise closed cell polyurethane foam. The float means is preferably integrally formed with the housing.

Preferably, the buoy comprises a submarine cable attached at one end to said wireless communications means and at the other end to a submarine assembly having signal detecting means, the signals detected by said detecting means being passed to said transmitting means for transmission to said remote station.

A third aspect of the invention relates, more particularly, to submarine assemblies and to submarine seismic sensing assemblies.

As described above, it has previously been proposed to provide a large number of signal detectors connected at spaced linear intervals to a line towed behind a vessel.

As an alternative to this system, it has been previously proposed to lay long signal detector arrays on the seafloor (the OBS system). Both of these systems exhibit a number of disadvantages.

The OBS system is disadvantageous as it requires a large number of vessels in order to be effectively employed. Furthermore, the laying of long arrays is inconvenient and expensive. The other previously proposed system is inconvenient as the lines towed behind the vessel severely reduce the manoeuvrability of the vessel and can become tangled. Furthermore, neither of these previously proposed systems provide particularly accurate results.

In accordance with this third aspect of the invention, there is provided a submarine sensing assembly comprising: an elongate mounting arm having one or more signal detectors connected thereto. Preferably, the assembly comprises: at least three signal detectors connected thereto, the first signal detector being aligned substantially perpendicularly to the mounting arm, the second signal detector being aligned substantially in parallel to the mounting arm, and the third signal detector being aligned substantially at right angles to the first and second signal detectors and to

the mounting arm.

This aspect of the invention alleviates the problems associated with previously proposed systems as it does not require the laying of long linear submarine detector arrays. Instead, a plurality of the submarine assemblies can be deployed, each of the submarine assemblies being more easily laid and subsequently recovered than previous systems. Furthermore, the particular arrangement of detectors employed in this aspect of the invention enables the accuracy of the readings taken to be improved.

Preferably, the first, second and third signal detectors are geophones. In this way, the detection of signals can be improved as the geophones allow the detection of shear waves. Preferably, the elongate mounting arm is of brass.

Preferably, one end of the arm is provided with an eyelet to which an anchor or the like may be connected to reduce drifting of the assembly. Preferably, the detectors are each mounted on the arm via a gimbal. Preferably, the submarine assembly comprises a housing within which said detectors are provided.

Preferably, the housing is provided with an eyelet to which a kelum grip or other suitable connector may be attached.

Preferably, the assembly comprises an umbilical connected at one end to the detectors of the assembly and at the other end to a buoy. Preferably, the umbilical is braided over its full length in kevlar fibre.

Preferably, the arm is connected to a spring rod and/or the spring rod is approximately 2m in length. Preferably, an acoustic transponder is provided on the end of the rod furthest from the arm. A second acoustic transponder may be provided on the other end of the submarine assembly.

Preferably, the submarine assembly comprises one or more hydrophones. More preferably, the assembly comprises three hydrophones. Preferably, the hydrophones are spaced from one another along the assembly.

A fourth aspect of the invention relates to marine vessels and in particular to marine vessels which are operable to recover the above described buoys and submarine assemblies.

As discussed above, there are two principal previously proposed submarine exploration systems. Both of these systems require long, linear arrays to be handled.

Towed Hydrophone Arrays are recovered onto large reels at the stern, for storage.

Maintenance has to be performed in water, usually whilst deploying or fully deployed from a smaller vessel. OBS cables are recovered over the bow, via a large diameter drum, acting as a cable-bend restrictor. Storage of the cable is in large'bins', (usually the vessels main deck, divided into one or more sections) and require to be fed into the bin via the stem to allow redeployment in the correct manner (in a first on last off sequence.). Maintenance here occurs whilst the cables are onboard. OBS cables allow access to individual arrays, which can be replaced if they fail. Towed streamer arrays require entire sections to be replaced. However, due to the nature of streamer work, where the equipment can be deployed and remain out for weeks or months without recovery, failures are less. OBS cables, on the other hand, due to daily recovery and deployment, suffer very great failure rates.

In accordance with this fourth aspect of the invention, there is provided a marine vessel comprising a conveyor belt that is operable to convey items from the surface to the vessel.

This aspect of the invention provides an arrangement which removes the need for a large diameter rotating drum and thus addresses the inefficiencies associated with the previously proposed arrangement.

Preferably, the vessel is a catamaran. Preferably, the conveyor belt extends from the surface, or from just below the surface, to the vessel. Preferably, the conveyor belt has a coarse mesh. Preferably, the conveyor belt is of kevlar.

Preferably, the conveyor belt is provided with engaging means that rotate with the belt and can engage with items floating at or near the surface to subsequently convey them within the vessel. Preferably, the engaging means comprises a series of stainless steel wire hoops. More preferably, the engaging means comprise two rows of hoops that extend from either lateral edge of the belt to leave a channel therebetween.

Preferably, a rail is provided either side of the belt to reduce the likelihood of retrieved items being washed off the belt. Preferably, the conveyor belt is attached at one end to one or more arms that are operable to move the end of the conveyor belt away from the surface. Preferably, the end of the belt is lowerable to an angle of up to 45° below the horizontal. Preferably, the end of the belt is lowered to an angle of approximately 32° below the horizontal during use. Preferably, the conveyor belt extends, in use, downwardly towards the bow of the vessel.

Preferably, a wheeled drive mechanism is provided within the vessel.

Preferably, the drive mechanism comprises four close coupled driven tyred wheels that can engage and transport any items retrieved by the conveyor belt. Preferably, the vessel comprises a storage rail mechanism within the vessel so that items retrieved can be stored. Preferably, the storage mechanism comprises a plurality of trolley units movably mounted on a rail, each trolley unit comprising a first trolley for supporting a buoy, a second trolley for supporting an umbilical and a third trolley for supporting a submarine assembly.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a submarine exploration system; Figure 2 is a schematic representation of a buoy; Figure 3 is a schematic representation of a submarine assembly; Figure 4 is a schematic representation of a marine vessel; and Figure 5 is a schematic representation of a unit of a rail storage mechanism.

Figures 6 and 7 are schematic representations of an illustrative catamaran.

The various aspects of the invention will now be described with reference to an illustrative deployment at sea. However, it should be noted that the invention may be employed in any marine environment, whether that environment be a freshwater environment or a saltwater environment. Accordingly, any reference herein to a marine environment or to a sea environment should be understood to include both fresh and salt water environments.

As in the known OBS system, two linear arrays spaced by 50m, for example, are set-up. In accordance with this example of the invention, each array comprises a plurality of submarine assemblies each connected to a respective buoy.

With reference to Figure 1, the submarine exploration system 1 comprises a plurality of submarine assemblies 3 each connected to a respective buoy 5. Each of the buoys is provided with an antenna 7 and transmitting means. An illustrative example of a suitable submarine assembly and a suitable buoy will be later described. The submarine assemblies detect reflected soundwaves and generate signals indicative thereof which are subsequently passed to the buoys for transmission to a remote station 9.

The remote station 9, which in this example is a marine vessel, is equipped with an antenna 11 and the appropriate equipment to permit reception of signals transmitted from the various buoys 5. The remote station may solely be employed as a signal receiving station, or more preferably may also be employed as a deployment vessel for deploying the submarine assemblies. An illustrative example of a suitable vessel will be later described.

In use, signal generating means (not shown) are employed to generate signals, for example soundwaves, which travel through the marine medium and through a portion of the earth therebelow. The soundwaves are reflected by transitions between different rock types and by other underground formations. These reflected soundwaves are subsequently detected by the submarine assemblies and signals are generated in response thereto. The detected signals are passed to the transmitters for transmission to the remote station. The sound generating means may comprise a pneumatic pulse generator, an explosive source or any other suitable signal generating means.

Advantageously, the signal generating means could be mounted on the remote station so that a single vessel may be employed for the generation and reception of signals, and for the deployment of submarine assemblies and buoys.

An illustrative example of a suitable buoy will now be described with reference to Figure 2. It should be noted however, that this buoy may be utilised with systems other than those described above.

As shown in Figure 2, the buoy 5 comprises an impact resistant housing 20 having an inner cavity 22. The cavity is sealable against water ingress by a lid 24 which in one embodiment may comprise one or more solar cells. An antenna 26 is spring-mounted on the lid 24 of the buoy and is connected to a signal transmitter 28 provided within the sealed cavity 22 of the buoy 5. The antenna may be provided with reflective tape 30 or other reflective devices to improve the visibility of the buoy.

Power means 32, for example batteries, are provided within the sealed cavity and are preferably connected to the underside of the lid 24 for easy removal therewith. The batteries are connected to the transmitter and to the solar cells, if provided, to supply power to the transmitter. The solar cells are provided to extend the time between battery charges particularly for those situations where battery recharging cannot easily be accomplished.

The transmitter preferably includes a flash memory so that a number of readings may be taken and then subsequently transmitted, rather than making large numbers of individual transmissions. Preferably, the number of available transmission channels corresponds to the number of signal detectors provided on the submarine assembly. In the preferred embodiment, the transmitter has six channels and utilises 24 bit delta-sigma transmission to provide a two way communications link to the remote station. Preferably, the transmitter uses a digital modulation technique to transmit data at a very high data rate over a reduced spectrum (for example between 68 to 88 MHz or 220 to 238 MHz). The transmitter is preferably a low power transmitter with a range of 4kms at 100 mW, 20kms at 1W and 35kms at 10W.

The underside of the buoy 5 is provided with an eyelet 34 to which a suitable connector such as a kelum grip 36 may be attached. The kelum grip 36 supports an umbilical 38 which is connected at one end to the transmitter 28 and at the other end to the submarine assembly (to be later described). The umbilical is attached to the buoy via the kelum grip to reduce the likelihood of the umbilical capsizing the buoy, and to reduce the strain placed upon the connection between the umbilical and the transmitter.

The composition of the umbilical will later be described in conjunction with the submarine assembly.

The impact resistant housing 20 of the buoy 5 is preferably of ABS plastic, or some other suitably tough material. The interior cavity is preferably filled with a buoyancy aid, such as closed cell polyurethane foam, that also defines suitably shaped cavities into which the batteries and transmitter may be inserted. The housing and buoyancy aid may be formed at the same time by an injection moulding process, for example, or may be formed separately and then subsequently joined. Preferably, the batteries are located towards the base of the buoy so that the centre of gravity of the buoy is kept as low as possible in the water. Any space above the batteries may then be filled with removable sections of closed cell polyurethane foam.

An illustrative example of a submarine assembly will now be described with reference to Figure 3. However, it should be noted that the submarine assembly described below could be utilised with exploration systems or buoys other than those described above.

With reference to Figure 3, the submarine assembly 40 comprises an elongate

mounting arm 42 which is preferably of brass or another dense corrosion resistant material. The mounting arm helps to keep the submarine assembly in close contact with the seafloor, and thus helps the geophones to couple effectively with the seabed.

One end of the arm 42 is provided with an eyelet 43 to which an anchor or the like (not shown) may be connected to reduce drifting of the assembly.

A first geophone 44 is connected to the arm 42 and is aligned parallel thereto.

A second geophone 46 is connected to the arm 42 and is aligned substantially perpendicularly thereto. A third geophone 48 is connected to the arm 42 and is aligned at right angles to the other geophones and to the arm 42. In this way, the three geophones are aligned along the x, y, and z axes with respect to the arm. The geophones may be directly mounted on the arm or, more preferably, they may be secured within a housing 50 that is mounted on the arm. It is further preferred that the geophones are each mounted on the arm via a gimbal so that they are correctly oriented with respect to the vertical.

The housing 50 is provided with an eyelet 52 to which a kelum grip or other suitable connector may be attached. An umbilical 54 (which may be the same umbilical shown in Figure 2) is connected at one end to the various detectors of the submarine assembly and at the other end (not shown) to a buoy, for example. The umbilical 54 is braided over its full length in kevlar fibre which is supported by the kelum grip so that the umbilical may be used to lift the submarine assembly upon the retrieval thereof..

The arm 42 extends beyond the housing and is connected to a spring rod 56 that is preferably approximately 2m in length. An acoustic transponder 58 is provided on the end of the rod 56 furthest from the housing 50. A second acoustic transponder 60 is provided on the other end of the submarine assembly close to the housing 50. The acoustic transponders 58,60 enable the location and alignment of the submarine assembly to be accurately determined. A spacing of 2m meters between the two transponders enables the alignment of the assembly to be determined to a resolution of better than 10 degrees.

In addition to the three geophones, it is preferred that three hydrophones are also provided. The first hydrophone 62 is preferably provided within the housing 50 and the second and third hydrophones 64,66 are preferably spaced from one another

along the rod 56. The combination of hydrophones and x-y-z aligned geophones enable particularly accurate readings to be taken.

An illustrative example of a marine vessel that is operable to retrieve the above described buoys and submarine assemblies will now be described with reference to Figure 4. However, it should be noted that the marine vessel described below could be used to recover a variety of alternative items.

Figure 4 shows a schematic cross-sectional view of a vessel 70. In the preferred embodiment, the vessel is a catamaran and only one hull 72 is shown in Figure 4.

As shown, the vessel 70 includes a conveyor belt 74 which extends from the surface, or just below the surface, to the interior of the vessel 70. The conveyor belt 74 is provided with engaging means 76 that rotate with the belt and can engage with buoys or other items floating at or near the surface to subsequently convey them within the vessel 70. Preferably, the conveyor belt has a coarse mesh and is of kevlar. In this way, the belt allows the water to flow freely though it so that any possibility of damage being caused to the belt is reduced.

The engaging means 76 comprises, in the preferred embodiment a series of stainless steel wire hoops that extend from either edge of the belt to leave a channel therebetween. A rail (not shown) is provided either side of the belt to reduce the likelihood of retrieved items being washed off the belt.

The conveyor belt is attached at one end to one or more pneumatic or hydraulic arms 78 that are operable to lift the end of the conveyor belt up out of the sea. The end of the belt may be lowered to any angle of up to 45°, but the normal operating angle of the belt is approximately 32°. In this way, the belt can be lifted out of the sea when it is desired to move the vessel at an increased speed.

A wheeled drive mechanism 80 is provided within the vessel and comprises, in the preferred embodiment, four close coupled driven tyred wheels that can engage and transport any items retrieved from the sea. A storage rail mechanism 82 is provided within the vessel so that the items retrieved from the sea can be stored.

Figure 5 illustrates a group of trolleys which comprise one unit of the rail mechanism 82 and which are particularly suited for the storage of a buoy and submarine assembly as described herein. As shown, the rail mechanism 82 comprises

a rail 84 and three trolleys 86 per unit. A first trolley 86 (i) supports the buoy 5, a second trolley 86 (ii) supports the umbilical and a third trolley 86 (iii) supports the submarine assembly 3. The trolley storage system is advantageous as it requires only a small amount of room on-board the vessel. Thus, a large number of buoys, umbilicals and submarine assemblies can be stored on board.

When used to collect buoys and submarine assemblies as described herein, the vessel is manoeuvred until the buoy is caught by the engaging means 76, whereupon the buoy is conveyed from the sea to the vessel. At the top of the conveyor belt, the buoy is lifted onto the first trolley 86 (i) and the wheeled drive mechanism draws the umbilical along the channel between the engaging means up the belt. The umbilical is then looped onto the second trolley 86 (ii) and as it is drawn into the vessel, so the submarine assembly is lifted from the seafloor and drawn towards the vessel 70 whereupon it will eventually be engaged by the engaging means 76 and lifted up onto the belt. The assembly will then be drawn up the belt within the vessel and then can be hung upon the third trolley 86 (iii) to complete the loading process for that buoy and submarine assembly. The process can then be repeated until all of the buoys have been collected or until the vessel has reached maximum capacity, whichever should occur the earlier.

Referring to Figures 6 and 7, there is shown an example of the vessel 70 showing optional booms carrying signal generating equipment. As mentioned above, it is conceivable for the present system to be employed from a single vessel.

However, to improve the operating efficiency, it is preferred that the buoys etc. are deployed from and recovered onto a first vessel, and that the signal generating means is provided on a second separate vessel.

As shown in Figure 6, the vessel comprises a catamaran having a storage area 100 between the two hulls 72. The catamaran also has booms 101, the ends of which are at least 60m apart. The booms are retractable and are provided with signal generating means 102 which, in use, generate signals for detection by the submarine assemblies..

As shown in Figure 7, the conveyor belt 74 of Figure 4 is arranged between the hulls 72. In the embodiment of Figure 7, two conveyor belts are provided-but a single belt or a greater number of belts may be provided if desired.

It will be understood, of course, that the invention has been described above by way of example only and that modifications may be made within the scope of the invention. It should also be noted that further preferred features of aspects of the invention are described in the attached appendix, and that the particular combination of features claimed is not limiting in that further combinations and/or permutations of features other than those specifically enumerated may be claimed. In other words, any of the features described herein (whether in the appendix or the main body of the description) may be claimed either alone, or in combination with any one or more other features described anywhere in the application.

APPENDIX A Brief. Lavman's overview of the McABS projects.

It is proposed to create a new company, operating two field crews equipped with Marinised Syntron Polvseis radio teiemetry seismic equipment.

What does this mean? Background: Seismic Exploration : Currently, oil companies explore for oil and gas by drilling, often very deep-and expensive-holes. This is not'blind'; they have many tools to assist in determining where to drill. Principal among these is the seismic section, a cross section of the reflective layers of rock below the surface. Generally, a change in rock formation will act as a reflective layer-and sedimentary rocks, often many miles thicic, will contain many rock changes. This is both in material-limestone to sandstone, for example-or density, aggregates to siltones, etc..

The medium used to locate these reflective layers is sound-acoustics; low frequency noise created by explosives, or pneumatic sources like high pressure tuned'air gun arrays', which simply make a very large bang under water. In the Marine environment, Seismic is the principal tool for looking beneath the earth's surface. The tool for listening to the returned reflected sounds is a series of phones buried in the ground. From these recorded returns, a picture of the sub surface is constructed, showing structures, hopefully with'oil traps' (reservoirs).

The Onnonunitv for new technolov-McABS.

The marine environment has a peculiar problem for seismic-the water medium is ideal for detecting the returning, reflected sound waves with towed arrays of hydrophones, devices that when compressed by pressure waves-the returning sound waves-generate a very small electrical impulse. This is performed by compressing a crystal in the'hydrophone'. The problem is only certain pressure waves can travel through water-if the Geophysicists require more information; they employ Geophones, which are directly coupled to the sea floor. These units employ a magnet suspended inside a coil, which when moved creates a small electrical curent. However, a significant problem is, that although the geophones have many advantages over the hydrophones, logistically it's a lot more difficult to deploy. And thus more expensive.

The nature of the Marine environment-often deep, frequently hostile, rarely quiet, and usually full of boats, ships, and fishing equipment-means care and thought is required to deploy any equipment to record the rezurning sound waves.

Currently, the bulk of the Marine seismic Industry employs towed hydrophone arravs. usually many of them, in streamers (up to 12, currently, with plans for 20, six or more Kilometres long, 50 or 100m apart, from specialised, expensive, purpose built vessels.) The Problem: However, a small market has developed, where Geophones are deployed, long Kilometresmaximum)arrays,(currently12 with dual sensors every 50 m. aresensors hydrophone,employed,one one Geophone, per point receiving location, to 'ghosts' in soundwaves,causedbytheseasurfaceactingasarefectionlayer.)Thi sreceived tec.-msue s caileå OBS or Ocean Bortom Seismic'Currently world wide there are less than 1 vs. due. o the hieh costs.

This market couid deveiop hugely, if the costs- currently more than twice thai of the towed couldbereduced.Themarketiscailingforgeophonesystems,arrays- (hence the expensive OBS ifasuperiorsystemcouldbeestablished,thenthehowever market would respond with expansion ofthe number or crews.

The Soiution: The McABS (Multi-component Array Bottom Seismic) is a solution to the 'stagnation' seen in the current Geophone placing technology, whereby four vessels are required. OBS requires a recording vessel, with Dynamic Positioning to hold its location, in any seas, whilst connected to the cables on the sea floor via vulnerable'jumpers'in the water column. A second vessel is required for the seismic source, to create the pulses of energy, usually pneumatic air guns, sometimes dynamite. Two more vessels are required to handle the huge Sengths of heavy, expensive cables, now at > 70 kilometers per crew.

McABS requires no dynamically located vessel-the recorder is on the second vessel, no longer required to be hard wired, but linked via telemetry buoys. So the relocation of the recording system onto the source vessel removes an entire, expensive, ship with crew, and associated duplication oferfbn. An Immediate reduction in cost.

By eliminating the need for cables to link the receiver arrays together, the second cable vessel is removed. We now have a logistically simpler crew with only half the operating overhead, doing the same thing! And the other advantaes: But-its potentially much better, because: 1. Employs 3 vari-axial geophones and three hydrophones PER ARRAY. A Geophysical improvement over received signals from the deep sub surface obtained currently.

2. Arrays can be varied to suit the requirement, not the cable dimensions.

3. Dragging long heavy cables onto ships and spitting them off the stern every day wrecks the cables-this is no longer required! Reliability is vastly improved.

4. Grater flexibility in marine environments- reslistically, OBS is limited to 120 meters depth-this method can go as deep as the client can pay for ! Whv hasn't his heen done before?- 1. This telemetry buoy technology is newly evolved-previous systems were single cnannel,nor appropriate to a marine, multi array.<BR> <BR> <BR> <BR> <P> 2. Concern over catching the buoys,-McABSdesignedradio concepts removes this possibility.

. Another problem is the handling of a large number or discrete buoys with arrays- again McABS has a fast, reliable solution to this. Other, more minor problems exist, but solutions for these are contained in this plan.

Conclusion: Borrom line of this project: A superior product. more flexible desivered. at half the withtheIndustriesmostexperiencedpersonnel.cost.AND Title: Rapid Buoy Recovery Device.

1. ABSTRACT. In order to safety but rapidly recover heavy, cumbersome telemetw buovs from the sea. a particular technique employing specialized equipment is required.

It is essential that this operation is totallv hands free. to reduce or eliminate any possible hazard to the Ships'crcev whilst operating in frequently difficult conditions.

Bv the use of a constantl moving mesh belt. deployed from the vessels main deck line. parallel to the ships hull. the buoys can be'scooped'out of the water, lifted to the ships main deck, where buoy is safely attached to an overhead rail for stacking inside the ship.

Recovery of the Umbilical, often in lengths of greater than 30m, also needs to be hands free, this is achieved by use of conventional four ATV tyred direct drive hydraulic wheels. Again, the cord is stacked on an overhead rail trolley.

Final item to comc onboard, now lifted by the 4-wheel puller, is the multi- component array, again lifted by the broad gap mesh conveyor system, deposited onboard onto the guides, and attached to the overhead rails.

2. Baclcground of the Invention. Seismic Companies have to respond their customers requests for more sophisticated products, the principal amongst these is to deploy Geophones on the seafloor, as an alternative to towed hydrophone arrays. There are many advantages to the use of geophones instead of hydrophone arravs. Prime amongst which is the geophones abilitv to couple directly to the solid sea floor. Thus the bottom placed Gecphone can receive and respond to sheer waves, which do not travel through water and thus cannot be recorded by hydrophones. However the increased cost of the bottom placed Gcophone normally precludes it being selected for use by most oil companies to survey their sectors. The majority of all marine seismic surveys are still recorded by the use of towed array of hydrophones.

Sufficient interest however in the advantages of the gcophonc in the marine environment. has lead to the support of a number of crews dedicated to the deployment of the Geophone. (Usuallv in combination with a close-coupled hydrophone, to create what is termed a'dual sensor'phone array.) These crews are called'Ocean Bottom Seismic'or OBS crews, and fill an important niche in the seismic survey market.

One aspect of the OBS operation that marks it out as difficult. is the need to frequcntlv recover the ends of the cables deployed at sea. This is achieved by maneuvering the cable vessci as close to the surface marker buov as possible. usually a Norwegian buov, or a Sonardyne ORT. an acoustically released device. Once close enough. a crewman must launch from the bow of the vessel a grapple hook. catch the rope beloxv the buos. and haul it onboard. The ropc is then placed into a four or eight-wheeled puller. over a large diameter wheel. All this is labour intensive and can pose quite a hazard. particularly if the weather is rough. or die currents strong. Trapped fingers arc common whilst putting the buoy rope over the bow.

It is also very inefficient, taking upto torecovereachbuoy.minutes Evidentially, there is a requirement for a faster. safcr more efficient recovery method.

Technical features: In order to produce long periods of totally rcliable service whilst working in very harsh, abrasive and frequently hostile environments, requires some over-engineering of construction and high specification materials. As such. the lower roller of the conveyor belt is mounted in heavy dutv. fully sealed marine roller bearings. Constructed of thick wall schedule 80 stainless steel. it is perforated with 30-centimeter wide 6 centimeters deep slots to allow water to pass through with minimal resistance. Diameter of 60 centimeters is required to prevent an undue bending strain on the umbilical cord connecting the surface control buoy with the Multi-component array on the sea floor, during recovery.

Over the lower free wheeling roller is a wide mesh chain mail conveyor belt. This again must be designed to offer minimal resistance to the passage of water through the belt. Attached to the underside of the belt at 25-centimeter spaces across the width. are 40-centimeter long prongs. These are stiff'catching'prongs, to arrest the buoy and carry it up the belt to the vessel main deck. Teflon covered side rollers on the rail sides reduce the drag on the buoy in its joumey up the belt, mounted in strong Stainless I beam supports for the lower roller.

The top roller is smaller diameter than the lower, and is constantly driven. Direct drive from a hydraulic motor ensures reliability and compact operation.

The buoy is carried to the top of the roller where it is dropped onto Teflon guides. A hook from the overhead rail system is attached to the buoy, and it is carried to the rear, using the same mechanism as employed on the ski lift T bar system. The Umbilical cord is caught between rotating tyres of a four-wheel puller, and pulled onboard. The Cord is looped onto a frame below the second roller as it is spat out of the puller; this is retrieving the array from the seafloor. Once the array is caught by the belt probes, and carried to the main deck level. the vessel can move onto the next buov where the operation is repeated. A third trolley is employed to carry the array, which is moved into the main deck for maintenance prior to re-deployment.

Diagram1.

1. Conveyor belt to 'scoop' Buoys from the water. Constructcd from strong and wide mesh Stainless stcel to offer minimum resistance to the passage of water, it has to withstand being driven through the water at up to 6 knots whilst still deployed.

2. A large Diameter roller freely rotates on the lower end. driven bv die large gap mesh. stainless steel chain mail. Constructed light but strong ; is perforated to allow free passage of water through the roller, to reduce to a minimum possibility of damage from heavv usage. <BR> <BR> <P> 3. Four-Nviieei puller to recover the umbilical cord, as it follows the buoy over the<BR> <BR> <BR> <BR> <BR> beit. The buov is suspended above the wheel by Teflon guides above the wheels, whilst the Umbilical falls through the guides between the ATV tvres of the puller. Recoverv of the cord shoots it in loops into a bin. which is attached to an overhead trolley.

4. Probes, attached to the underside of the stainless steel mesh of the conveyor belt.

Strong enough to take the weight of the buoy without being bent backwards.

Located every 25 cms across the width of the belt. in rows 2 meters apart. to catch the buov.

5. Activating arm of hydraulic recovery ram. to lift the entire conveyor belt up to the main deck level when not in use. Required for high-speed transits and bad weather periods. Constructed from Stainless steel to offer maximum protection from corrosion. bearing is fully sealed.

6. Bridge extended over side of vessel, with Storm proof windows located to allow full view of the lowered conveyor belt. Thus recoverv of die buoy is remote and totallv hands free, allowing maximum maneuverability of the vessel to position for the buov scooping.

7. Trolley on overhead rail svstem. similar to the T bar recovery system for Ski slopes. Removes the equipment to the main deck. where it can be worked before re-deployment.

8. Surface control Telemetrv. Nonvegian or ORT (acoustic release) buov 9. Multi-Component buov being recovered up the conveyor belt. pulled by the Umbilical cord being recovered bv the four-whcei puller.

1. Title : Multi-Component Arrav seafloor Seismic Instrumentation. <BR> <BR> <BR> <BR> <BR> <BR> <BR> <BR> <P> 2. ABSTRACT : To place on the Sea Floor devices to record returning sound waves<BR> <BR> <BR> <BR> <BR> acontrolledmanner,inordertodeterminetheraypathfromtheenergyg eneratedin <BR> <BR> <BR> <BR> therecordingdevice,requiresexpensiveteeliniqueswithsophistic atedsourceto recoveryineehanisins.depioymentand By employing a much-modified six-channel radio Telemetm product in the manne environment allows the recording from a single point on the sea floor of six discrete recording devices, with any combination of geophones and hydrophone. 2 meters separation of two attached but discrete transponders allows determination of geophone orientation as well as accurate location (sub meter) on trie sea floor of the geophone and hydrophone array. Data recorded is stored in internal Flash inemorycards until UHFradio,locatedonthesurfaceinacontrolbuoy.Thisbuoy,poweredd ownloadedvia by battery and solar ipanels. receives control commands from the Source Vessel.

No separate recording vessel is required, the multichannel recorder being located on the buoy-handling vessel. An umbilical, selected to be 1.5 times the deepest water depth of the survey area, connects the array on the sea floor via 12-core cable, to the control buoy. oftheUmbilical,withKelumClampattachmentstothebuoyandtheKevla rbraiding array, allows the umbilical to be strong enough to lift the amy from Sea floor.

3. Background of the Invention.

Manne Seismic Exploration is currendy divided into two discrete methods.

A./Principal method is for a vessel to toiv streamers containing arrays of Hydrophones, wlicii record returned sound waves generated, usually, by a pneumatic source, either also towed behind the same vessel or a second vessel. Although very successful. and accounting for the majority of all seismic surveys recorded to date. this method does have some disadvantages. The largest disadvantage is the use of therecordingofsheerwaves,whichdonottravelthroughthewatermedi um.Hydrophonesprecludes Other disadvantages include the susceptibility to generatednoiseinsurface pour weather conditions. controlofavesselusuallytowinginuitiplestreamers,makingitnavi gational impossible to come to a stop. and also long time consuming turns to prevent the towed streamers tangling.

Very sophisticated acoustic and tracking mechanisms are required to détermine the exact location in real time of tiie dynamically moving arrays in the towed streamers. responseB/.In to ExplorationIndustryrequirementformoredetailedrecordedOil information, a second OccanBottomSeismic(OBS)hasevoivedtoplacegeophonescalled (usually in combination wuli Hydrophones), at the same location on the sea floor. Vast numbers of arrays are tobeconnectedtoastationaryrecordingvessel,tofeedbothpowerdow ntherequired long - often 12 Kilometers - cables, and record the array signals generated from sound sources. Most of the associatedwiththetowadstreamersareansweredbytheadoptionofOBS systems,significantproblems but other problems result.

The major problem widi a Bottom Cable is cost-it requires four vcsscis. as opposed to trie one or two of towed streamer. to facilitatc recording. due to the recording vessel now not beuig able to tow the seismic source. The Huge amounts of cable required also require multiple vessels to deploy and cables.recoverthe To problems,athirdtechniqueisrequired.Thisisthesubjectofthisthe se Patent.

C.dio i cTcicmctrv buoys. dcpioycd in the manne or fresh water environment. to record muitiple numberofvesselsrequiredishalved,unreilablecablesareremoved,a ndmultipleThe geopliones/Hydroplionescanbedeployed.OrtentationoftheGeophon eaxisinthecombinattensof isrequired,andthisisaccemplishedbyuseoftwoSonardyneTZ7815tra nspondersorhorizental@@ane equivalents.Digicourse2410 Technical features: Details of the MulLi-Component Army Bottom Seismic system: Diagram 1.

Shows the surface buov, constructcd to surviveimpact impact tlie recording vessel. and rough treatment on recovery and deployment. A tough ABS plastic skin surrounds Poiyurethane. closed ceil notation medium. A molded anchor point on the underside is for the attachment of the Kclum grip, (Chinese Finger) to impart forces direct from the Kevlar braid on the Umbilical to the buoy body. This then prevents undue strain on the umbilical connection, whilst maintaining a direct pull central on the buoy vertical axis.

Inset into the top surface of the buov are large area solar panels. to maintain battery life for extended periods of operation over many days. They are sufficient for Duller Northern latitudes. The buoys, in periods of non-use, have a'sleep'facility to preserve battery life. Quickly removable batteries are employed, to be changed and re-charged every time a buoy is recovered at the end of its recording period. The Antenna is a rugged, fully marine UHF unit, capable of iulstanding some harsh treatment without damage. AH connections, for the batteries, antenna and umbilical, are fully marinized bulkhead connectors.

Diagram 2. Shows detail of the Umbilical cord, used to connect the array on the sea floor with the floating control buoy on the surface. A fully waterblocked 12 core cable, 16 AWG tinned cadmium Bronze 7 x 6 x 32 stand cable is used. End connections are fully marinized bulkliead connectors. being double 0 ring sealed. Pins are gold plated to prevent corrosion from seawater when opened for maintenance on the vessel decks. Length of the Umbilical is to be 1.5 times the water depth This will allow the cord to respond to current pulls without lifting die array from die sea floor. Excessive length will prevent the appro. xisnate location of the buoy to be known, and make navigating past the buoy without impact by the source vessel very difficult For example, in 30 meters of water, maximum, 45 meters of cord will be required. Thus for surveys in different areas, an inventory of different length cords will be required. Maximum water depth of operation is only restricted by the build specifications of the Umbilical and arma units. as the surface buoy, altlough fully marinized is not required to be pressure sealed. This improves reliabilitv enonnously, and extends the operating depth of the ystem beyond those normally encountered in OBS survens.

Diagram 3. Shows die detail of the array employed on the seafloor. Three Geophones. aliened in three different axes, are employed. All three geophones will be gimbaied. to remove die requirement of the array to land horizontally, not always a practical possibility. To prevent the array being moved once settled on the sea floor and improve coupling of the Geopliones with the bottom medium, a heavy, non-maenetic, non-corrosive metal rod is molded into tiic array, along the axis of one of the geophones. One end of the rod has an eye, for attachment of a small sand or Bruce anchor to also resist movement. particularly in areas of strong tidal currents. A mount for the acoustic transponder is also incorporated here. This allows accurate location of the array when it lias settled on the sea floor, to better than 1 meter resolution. ordinarily. Two hull mounted transducers on the buoy deployment, or source, vessels arc required, and this operation is independent of trie seismic operation. (For Interest seismic acoustic frequencies are in the range of 3 to 123 Hz : die transponders operate in 40 kHz frequency range.) A spring rod, plastic covered spring steel, is attached to the other end of the brass rod. to allow it to always be orientated in the direction of the rod. This is 2 meters long, with a second transponder located on the far end. This second unit is required to produce a second location for the array, from which via established RGPS algorithins the orientauon of the rod and hence the Principal arra Geophone. is determined to better than ten degrees. Also located on this rod are two Hydrophones. These extra two channels are recorded to improve the signal/noise ratio of the final product. reduce the effect of multiples. by combination of the signals with the opposite polarity geophones. and improve the flexibility of the arrays usage.

1. Tough, High Visibility ABS impact rcsistant tough plastic'skin'for the bodv of the control buov. This is to contain the electronics and the UHF radio. protect the flotation matenial, and offer a platform to mount the electronics, solar panels and die batteries. A molded eyelet on the underside of the buoy allows for attacument of the umbilical Kelum gnp, (Clunese Finger).

2. Closed cell Poiyuathene foam. to maintain buoyancy and form for the control buoy.

Easily repairable on the crew if damage.

3. Large capacity, sealed batteries, attached to the underside of trie solar panels for quick release and replacement, extend down deep inside the buoy, to maintain the center of gravity of the buoy to be as low in the water as possible. This will maintain an upright orientation at all times for trie maximum range of the antenna. Spare volume above the battery is closed cell polyuathene foam. molded as part of the battery.

4. Solar panels mounted to the top of the buoy, with a large O ring seal undemeadi to act as the top plate and prevent seawater ingress into the buoy body. A single cable connects the pancilbattery to the electronics box, via a fully marinized bulkhead connector. This to expedite rapid changeout of the batteries, and maximum reliability. The Batteries are secured directly to the underside of the panels. Attachement to the buoy body is via quick release single turn stainless connectors.

5. Electronics: Minimum 6 Channel system, with flash memory, and the latest leading edge low power UHF radio. 24 bit Delta-Sigma technology with two-way communications.

The central Recording unit, located on the Buoy vessel, can remotely program the Buoy, controlling due K-Gains, complete instrumentauon and seismic Quaiity Control monitoring, and customize the processing software. Single Interface cable connector for the Umbilical Cord, mounted on the top of the anodized Aluminum case body, widi a second connection for trie marine antenna. Download of the stored data is at the convenience of the Buoy vessel, being at the completion of the designed shooting patch array line. whereby the buoys are recovered prior to re-deployment at the other side of the rolling patch.

6. Antenna. Fully marinized. rugged and flexible, built to witlistand the harsh environment, accidental mnriing over of the buoy by the survey vessels. and for maximum range. Being mounted at sea level ; the ground plane effect will maximize the range attainable.

7. Reflective tape on antenna. to allow detection of the buoys at night by use of the vessel searchlights. Renecuve tape is also bonded to trie outside of the ABS plastic buoy bodies.

8. Umbilical Cord. This feeds the signals from the six phones located on die sea floor to the electronics in trie control box, where it is stored in the flash memor. Connecuon is via a fully mannized Bulkhead connector. To prevent any strain on this connector, and prevent any turning moment of the top mounted cord tending to pull the buoy over. the cord is attached to the eyelet under the buoy. The Cord is braided its full length in Kevlar fiber. to allow the umbilical to be a strain member. and the lifting mechanism for the array on die seafloor. It is important that no strain is imparted to trie conductors in the Cord.

9. Kelum grips, or Chinese Fingers. are used on the top and bottom of the Cord to attach, via a quick release Carabina Stainless Connector, die grip to the eyelet. This maintins the buoy in a vertical inpoorweather,improvingvisibilityofthebuoyeven and radio range.

Figure 1. The Surface control buoy. 7 5 1 4 0 \ 9 3 Figure 2. The Umbilical Cord. | 10. Hydrophone &num 1, built in. part of the 4C (four Component) army. Rated for 400m or deeper if<BR> <BR> <BR> <BR> <BR> Industry requires.

11. Hydrophone # 2, on flyead from array body. Attache to the spring rod claim 13 12. Hydrophone # 3, on end of flylead. Attached to the spring rod claim 13.

13. Spring rod. Plastic coated stainless spring steel, firmly attached to brass rod. claim 14, parallel.

This is a support for the acoustic transponder located on the spring rod end. Length two meters.

Can be increased if required, but shoner length is advantagous in on boardtandliny of array.

14. Brass rod. Non metallic, non corrosive dense material. Weight approximatly 10 Kg. To aid coupling with the sea-floor. To allow spring rod to be attached parallel to the prime Geophone axis. Claim 14. Eyelct on one end for attachment of Bruce or sand anchor to prevent drugging by surface buoy in currents, and attachement for acoustic unit. Claim 18. Other end of Brass rod is extended to allow attachment of the Spring rod. Claim 13.

15. Gimbaled Geophone &num 1. Vertical axis, Conventional response to imparted energy from earth. opposite to that of Hydrophone. (for flat seafloors, it's not nessisary to Gimbal this Geophone.) 16. Gimbaled Geophone ? 2. Horizontal axis, parallel to the Brass Rod. claim 14.

17. Gimbaled Geophone &num 3. Horizontal axis. at right angles to that of the Brass Rod, claim 14.

1S. Acousuc transponder. To locate the array on the sea floor, using high frequency acoustic pinging methods, whereby as die source or Buoy vessel passes the transponder, ranges are recorded to the unit. Determination of die Array location is derived by knowine accuratly the locations of the Hull transducer in die Vessel employed to ping the unit Multiple ranges increase the accuracy of the derived fix.

19. Second acoustic transponder. This unit is required to determine the orientation of die Geophone arrays, required to process the impaned energy waves impinging on the Geophone. A Resolution of better than 10 degrees is obtained with a seperauon of 2 meters. Figure 3. Nlulti-Component Array. 9 3 10 19 1 is t'il 12 11 ' I '4 t5 ;,'7 I 1 0 I IS 1 17 , 0 Radio Frecuercies: 6S-SS NiHz. 400 kbits dataratt. Or altemmvly 220-238 hQ-iz.. 3Z,, t je,tive iape Radio aananissioa usa a dli2ital modulation technique to transmit data at very hizh data rate in reduced radiowave Spring loaded stainless antenna. specuum Ranges of 4 Kms are ed Anchor power as low as 1000 uuiliwnrts. W With one watt raaats of 20 Kms apte attinable, ten watts for 35 Kilomters. The sea surtace acu as a base plane. Ego-tronc: mimnisni Poissais second gene : auon svstea. with radio power management Aquires 6 channels. tNlst Ls QC header burst every ShotpoinL stores n Recas m top: Stainless steel tnv seismic dae in dash metneory unul m mossmsng est solar partels for time penncs co download. (on roU,yj :. operations ia Norchern Iatitudes. Of feCCiYtf 1111e.)ljS SSVts bauj=v Life, allows 24 hr ope=on module, two rei=sc larr of receiver line.) This saves -nhr BMon":! Qutdc &sss '= in OVCM= northern latitudes. nisme capa-Y 0 ooanaaions-baaay maz baxay md deployed Thick wtll A. B. S moulding a. ffe. >swab with P. U. foam fillis ìo Speciticanons: c3pabiliue5 in excess of 8000channets. amonmsmgK.-Gam to Closed cell PU faaal optimise overall dynarltc rangee, data y". psscesssag in the RTU (poue- ; _ : _ :-... _. =_ matching, synchromzaaon. noise editing, vertical or diverstty sttking aadcoae3ation.) Streinrelief from RTU (remote telemetry unit) can be and kelum (chinese .,/6nger) chmp. Error correcuon svstem to encre= data J sntessrisv !. Umbilicalcord-U core kevtar shrouded/ uble lenzbs to suit operation. Le 3m wcer depth uses 45m cord. 200m water pth uses 300m cord. For shallow depths excess cord is tareed up using kellum clamps, to prevent rogue buoy locations. An-aycord Heavy Brass sage=ertoamich (Umbilical) is l. 5 sonardtme tlylead. improve coupling timp-q wntpr need for chaitv wcght& 10 4 m toth to detennine -from sonatdynes locations and onentanon- Kallum gnp sQain reiieC attachment Stiffn : ed flyltad co hold sonardvnes to eye'ptsveaa along to Optional along aaay zrcis to detamie oientatioa Ctranrv, i In hraev enti'. r, rr rrtrnann aLLICC fOT aachor. for heavy Sonardyne Sonardvne so=-i- unis 1. i ..... : : : : :. ° = °] v. : : : : : : : : : : :, : when 1. 9m overall | _ p J 0 110) ol 0 po) F P t°1 P 97 K =S <'T _whenstacked. O O O OJ Tether line . I between trolleys ABS Telemeay buoy Buoy 0 0 4C anay, with brass heading rod, acoustic Umbilical booms Rail required: 0.8 m for buoy, 1.1 m for loops and array, = 1. 9m / unit. 625 units requires 1190 m of rail, with 40 m of deck, require 32 rails, 0.8 m apart. Source vessel will have backup but reduced rail capacity, for backup buoy collection and transits, with spares. (125 of.). ; D C-* 4 g WEa ; beployrner. t . : :... Conveyar Hd Stbd. Side PtcY. Rails, slide port to stbd adj.,--a--a trridge tmmbilical To axcss iadd n Pia dmps buoy. cable arsc. /V <) 1 r c C) ' 1 r Modified existing vessel for season 1997 whilst wading on jet drive c3ts. Propellers need to be shrowded with cage. (0) Hydmuiic ran j I 0 \ 1 >C I, > (oConveyor belt S. S. meth with 8 inch pins Buoy,totallyhandsfreetocatch bu@@to@@@@@@@@@@@@tionDeliver@ Rails required : 4c array, toops & Buoy require 1.9m of rail; assume working deck 40m long, rail to be 36m long, i. e. 19 arrays. This is sufficient for 3.7 Kms of layline with 200m spacing. For 10 sq.kms requires 10 rails, at 400m receiver line Thus can lay 190 arrays.

If require 100 m x 400 m arrays, require 20 rails for 380 arrays.

Vessel loaded for 500 arrays, requires 27 rails For this vessel needs to be 30 m working beam.

. kltcmadve is two boats. to aa as buoy vessels. Too expensive. <BR> <P>Solution: upper deck of rails. I. e. two decks. With powered trolley delivery between decks. Spares and dameed buoys on upper deck.

This layout is for the convened vessel prior to the catamaran being delivered. Props will need shrouding as wiU rudders.

Jet drive on car will elimmate this concern. - vim o of bow deell c r d ° 0 wholelength, or Equiv.'t Q aJJm'av.'- full bm 1g. f r tX<tFor 2 jj wifwlle, nwAww, 1 J I stup. r Y"Ship* am » \ I Chin _ > sewagt oil deancivea Liff Fne mom : Elteic upamm cm_ 1600 Cf= UM= cinvm je% m pa > _ Ihls _ SpXlt sr 1600 ehZl IllI&i _ driven jets, « C pX _ 8 _tinil oovt Doots, as per hrziing craft. two conveyor belts. SS chninlink with 8 inch spikes. Port Hull : Whist in traaiit are 40 deas. Stb up from Pivot point, for buoy Hui iasanmmt recovery are 40 degrees down. See dctail. F4 _ Working dxlc Capaary 625 RTUs vta ovaaesd rails min. Pa vessel. Depiovmc= 625 R= @ 1. 9 in perrmi-1190 ma=AaiL Worivng deci 40 m long rails. oa seda : Rxovay tail at bow door. 5m long, ', 4m long depioyme rsil at stem. Pivot po= 2 40 in long mlis, with 1. 9m i a=y, (buoy O. Sm coils. 0. &zL zm 0. 3nL ot hyd=uiic cmT= 21 armys/rmL For full capaeity. icctuding the ZS% sp, teqsmes 57 maveyac bdis rails. Rails ae 0. 5 m apt whm loaded 30 ma forI f « dss ß PmcedzsrNired. tcwvay 1. To prl-vem rmls fr= rolling to port =d stbd. Due to ships motion 2. To reduce tbe deasity of apmt, the goa boat will cany the spes, this will be eqmpped with bow dorez deployment rails at staa, to act as bacfom for acptd recovay eg. Winttr gaia ia sbaliows, sowhea Norsh Sc eccaampla 3. Smooh astionom recovay rail to starage tail, to deployment rait SOUMCI IS mG : I I 1 15 me :Urn : : | deilectlon. overall outcr I tooutcr60mrequi 1 U s 1 i 1 1 liez Front vlheel puller Wre ; ,,, 7es3 .. :" ! ! ! \ W1N. -,: ='-.: i'. aulic dirct drir_mafor: 1I metes i Cons, belt loops.

To collect Polyseis buoys from the sea, hands free, during inclement weather, and allowing fast operating speeds.

The system is a strong, stainless steel frame, 11 metres long, 1.2 meter wide. The pivot point is 1.5 meters inside the top, where the direct drive hydraulic motor is located above. This drives a coarse mesh conveyor belt, of Keviar weave. This construction imparts minimal frontal area, and thus resistance, to the sea action, allowing water to now directly through the mesh, reducing the possibility of swell damage.

Attache to the underside of the mesh and projecting through 45 cms long, are stainless steel wire loops, 9mm diameter, extending half the width of the belt. Two loops are side by side, with a gap between of 12 cms to allow the Umbilical to trail through. These wilI catch the Telemetry buoys on the underside, and convey up to the 4-wheel puller on the vessel main deck A rail system I-meter tall extends the length of the platform, to prevent the buoy being washed off the side.

Hydraulic recovery of the platform, for stowage whilst underway, is effected by a beam action on the lower free rotating drive pulley. A hydraulic ram located above the ships moulded side acts on the beam, to force the platform up. This keeps the ram out of the water, and prevents corrosion.

Angles of 45 degrees are availabie, but normal operating angle will be 32 degrees. a Hydraulic diive, direct coupkd. / 0 Hydraulic dnve. dllect coupled. Pil PotPm emetry Buoy . _ __ _. _ Celeme ry Buoy bef just br n This system replaces the Large diameter drum on a conventional Ocean Bottom seismic vessel. This drum is vunerable, requires manhandling of the buoys, and quite inefficiant.

The system comprises a retractable conveyor belt which is safely stowed in very bad weather, offers little resistance to water passage, and totally hands free.

The buoy is collecte at the wateriine, and deposited onto the 4 wheel puller, (guides over, to sit the buoy on whist the buoy is attached to the rail trolley and pulled aft). The puller then recovers the umbilical cord. This equates to a significant improvement in RELIABILTY, and thus a massive reduction in downtime. _ _ _ _ = _ r_ I I i I l, ° r : nTf7 L$ =Zz l0tE< z v < t tZoo time ivo lu E a -, Floating Telemetry buoys on the sea surface are a hazard : this problem can be overcome by the use \ of two solutions: 1. Design everything such that it can survive being impacted. This means using jet drive propulsion, smooth gun umbilical lines to the tail of the array, and resiliem telemetry buoys and antennas. 2. Do not use the Industry standard Baravanes to achieve wide spreads, but wide beam catamarans and booms. ofBaravanes:Boomsinstead catamaranExtrawide solutionforspread.hasthe 1 1 X r l Access to tvorkin deck, and I/systev'=_ \ I/.., \ \ X = 4 ..-__- __---- ..-. ___ _ : _ __-_- 9 metets 12 mctecs 0 0 U D lJ OIJU U UIJIJ 9 IE ? D czn baLse of- _ . _ _