NO20161488A1

NO20161488A1 - Apparatus and method for retrieving data acquisition units

Info

Publication number: NO20161488A1
Application number: NO20161488A
Authority: NO
Inventors: Kyrre J Tjøm
Original assignee: Idrop As
Priority date: 2016-09-19
Filing date: 2016-09-19
Publication date: 2018-03-20
Also published as: NO342326B1

Description

The invention relates to an apparatus and a method for retrieving data acquisition units floating in a sea and bringing the data acquisition units aboard a vessel.

A data acquisition unit comprises one or more sensors for sensing data, and means for storing the sensed data. Sensor should be taken in its broadest meaning, as any device that can detect changes in its environment. One kind of data acquisition unit is a seismic node which before data acquisition is lowered to a sea floor. Seismic data are sensed and stored in a memory in the seismic node, and then the seismic node is raised to the sea surface by increasing its buoyancy, e.g. by releasing a weight. The seismic node is then brought aboard a vessel, and the seismic data are retrieved from the memory. Other kinds of data acquisition units are used for sensing environmental data such as atmospheric pressure and seawater temperature for weather forecasting or science, or for military purposes. These data acquisition units may float in the sea during their data acquisition.

Data acquisition units may be provided with pick-up buoys attached by ropes. The data acquisition units can then be retrieved from the sea by throwing out a heaving line with a hook from the vessel, and hook the pick-up buoys and haul them in together with the data acquisition units. The heaving line is typically thrown by a pneumatic heaving line thrower. The operation may be risky for the crew, and is quite slow. The pick-up buoys may also be picked up by a long boat hook, but this necessitates that the pick-up buoys are close to the vessel, which is risky since the vessel may damage the pick-up buoys or data acquisition units.

The purpose of the invention is to provide an apparatus and a method for retrieving data acquisition units floating in a sea and bringing the data acquisition units aboard a vessel, which apparatus and method shall be efficient and safe both for personnel and the data acquisition units, or at least provide an alternative to prior art. Further purposes and advantages of the invention and how they are achieved will appear from the description, the drawings and the claims.

The invention relates to retrieving data acquisition units for any use.

The invention thus relates to an apparatus for retrieving data acquisition units floating in a sea and bringing the data acquisition units aboard a vessel. According to the invention the apparatus comprises:

- a line with hooks for catching the data acquisition units;

- guiding means for the line, arranged to:

- guide the line in a path substantially at the sea surface, hooks of a catching portion of the line have an elevation suitable for catching the data acquisition units;

- guide the line between the sea and the vessel;

- guide the line on the vessel, to a location for releasing the data acquisition units from the hooks;

- a support structure for the guiding means; and

- a driver for pulling the line.

The invention also relates to a method for retrieving data acquisition units floating in a sea and bringing the data acquisition units aboard a vessel. According to the invention the method comprises:

- arranging a line with hooks in a path substantially at the sea surface, hooks of a catching portion of the line have an elevation suitable for catching the data acquisition units;

- moving the vessel forward, the catching portion of the line moves towards and hits the data acquisition units;

- pulling the line, causing the hooks of the catching portion of the line to catch the data acquisition units;

- pulling the line with the hooks and the data acquisition units aboard the vessel, and

- releasing the data acquisition units from the hooks.

"Line" shall mean any load carrying member able to carry the data acquisition units, and shall include segmented or continuous cables and belts.

Preferably the line is a continuous line. The line may be arranged in a path substantially at the sea surface, and another path at the vessel. These two paths may be interconnected in an area between the sea and the vessel.

The guiding means for the line may comprise sheaves. The driver for pulling the line may be one or more driven sheaves, driven by e.g. electric, hydraulic or pneumatic motors on the vessel.

The support structure for the guiding means may comprise a base for supporting the guiding means on the vessel. The base may be a steel structure made of beams joined together. The steel structure may be attached to the vessel by bolting or welding.

The support structure for the guiding means may further comprise an arm with floats for supporting the guiding means in the sea. The floats may be interconnected by rods or beams. The arm is then formed by a row of floats spaced by the rods or beams. The rods or beams may be telescopic, which can be advantageous for adapting the length of the arm to various operational conditions or the length of the line.

The rods or beams may be connected to the floats by movable joints, which allow the floats to move individually in the sea in directions allowed by the joints. Compared to stiff connections between the rods or beams and the floats, movable joints reduce or eliminate application of torque, transverse forces and bending moments from the floats to the rods or beams, which means that the stress on the rods or beams is reduced.

The position of the arm during forward movement of the vessel may be maintained by positioning-ropes to the vessel. Further, the arm may be provided with at least one deflector or thruster for pulling the arm away from the vessel during forward movement of the vessel.

The base and the arm may be connected by an intermediate part. This intermediate part may serve to support the guiding means, i.e. the sheaves, for the line between the sea and the vessel. The intermediate part may further serve to hold the arm in place in the sea. Preferably there is a movable joint between the intermediate part and the arm, in order to allow the arm to move in the sea. The intermediate part may be an inclined rod or beam sloping from the vessel to the sea. The intermediate part may, however, have other shapes, e.g. a frame with a horizontal beam pointing out from the vessel, and a vertical or sloping beam attached to the end of the horizontal beam, pointing down to the sea for connection to the arm.

When retrieving data acquisition units floating in the sea according to the invention, the vessel is moved forward, and a portion of the line with hooks facing the data acquisition units, i.e. the catching portion of the line, moves towards and hits the data acquisition units. The line is pulled towards the vessel, and the hooks of the line hook and thereby catch the data acquisition units. The line pulls the data acquisition units towards and aboard the vessel. The line transports the data acquisition units to a place on the vessel for releasing them. The releasing of the data acquisition units can be manual or automatic.

Some data acquisition units may be missed by the hooks or fall off the hooks in the sea. For catching these data acquisition units, a net may be suspended from the arm.

The invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 illustrates the afterdeck of a boat with an apparatus according to the invention;

Fig. 2 illustrates an enlarged part of fig. 1; and

Fig. 3 illustrates the afterdeck of a boat with another embodiment of the apparatus according to the invention.

Fig. 1 illustrates the afterdeck 26 of a boat 1 moving forward in direction 3 in a sea 2. The boat is provided with an apparatus for retrieving data acquisition units 4 floating in the sea 2 and bringing the data acquisition units 4 aboard the boat 1. In short, this is achieved by a line 5 with hooks 6 that catches the data acquisition units 4 in the sea, and which is pulled aboard the boat 1, in which the data acquisition units are released. When in the sea 2, the line 5 is supported by a floating arm 12, and when on the boat 1, the line 5 is supported by a base 11.

The arm 12 comprises floats 13a-d interconnected by rods 15a-c. Float 13a is farthest from the boat 1, float 13b is second farthest, float 13c is second closest, and float 13d is closest to the boat 1, at the side of the boat.

Fig. 2 illustrates the floats 13a and 13b in more detail. The floats have lower buoyant portions 17 and tops 18. The floats also have not illustrated bottom weights that ensure that the tops 18 are pointing upwards. The floats 13a-d, see fig. 1, further have guiding means for the line 5 formed by free running sheaves 10a-d located between the buoyant portions 17 and the tops 18. The buoyancy of the floats 13a-d is such that the sheaves 10a-d are located slightly above the sea 2.

The rods 15a-c are connected to the float tops 18, but could have been connected to other portions of the floats. The rods 15a-c are telescopic and can be set to a length that provides a specific distance between the floats. The length of the rods 15a-c can be set automatically by hydraulic or electric means, and can be remote controlled from the boat. Alternatively, the length of the rods can be set manually, e.g. by providing inner and outer parts of the rods with corresponding holes that can be locked to each other in different positions by through bolts. If the telescopic function of the rods is not needed, the rods may be made of ordinary steel tube.

The rods 15a-c are connected to the floats 13a-d by ball joints 16. Within certain limits the ball joints allow relative rotation in any direction between the rods and the floats. This in turn allows transverse movement of the float in the opposite end of the rod. In this way the floats 13a-d may be moved by the sea without applying torque, transverse forces or bending moments to the rods 15a-c, and thus the floats do not cause twisting or bending of the rods, which could damage the rods. Positioning-ropes 23a-d, see fig. 1, extend from the floats 13a-d to a not illustrated attachment point at the side of the boat 1. When the boat 1 moves forward, drag from the sea 2 on the arm 12 will push the arm 12 backwards and tighten the positioning-ropes 23a-d. By adjusting the length of the positioning-ropes 23a-d individually, both the shape of the arm 12, i.e. the relative position of each float 13a-d in the arm 12, and the direction of the arm 12 relative to the boat 1 can be adjusted. In fig. 1 the arm 12 has been adjusted to a straight arm extending transversely to the longitudinal direction of the boat 1.

The base 11 is a welded beam structure, fastened to the afterdeck 26, e.g. by bolting. The base 11 has free running sheaves 10g-j for guiding the line 5 on the boat 1.

An intermediate part 27 connects the base 11 and arm 12. The intermediate part 27 is formed by an inclined rod 15d which extends from the afterdeck 26 to the sea surface at the side of the boat 1. The inclined rod 15d is connected to the arm 12 by a ball joint 14, and is connected to the base 11 by another ball joint 28. Similar to as explained above for the ball joints 16 of the arm 12, the ball joints 14 and 28 allow rotational movement of the float 13d and the inclined rod 15d. This allows movement of the float 13d by the sea without applying torque, transverse forces or bending moments to the inclined rod 15d, and also allows adapting the inclination of the inclined rod 15d to the movement of the float 13d in the sea. The inclined rod 15d is provided with driven sheaves 10e,f for pulling the line 5 and guiding the line between the sea 2 and the afterdeck 26 of the boat 1. The sheaves 10e,f are driven by a common electric motor or by separate electric motors (not illustrated).

The illustration of the sheaves is simplified. Not illustrated guiding rollers ensure that the line 5 is kept in the grooves of the sheaves. The line 5 is guided in a path both ways along the arm 12 by means of the sheaves 10a-d. Sheave 10a farthest from the boat 1 is a turning sheave. The driven sheave 10e pulls an ingoing portion 7 of the line in direction 19 towards the boat 1, which in turn pulls an outgoing portion 8 of the line in direction 20 away from the boat 1. Since the sheaves 10a-d are horizontal, the path of the line 5 is also horizontal. Further, since the sheaves 10a-d are located slightly above the sea, the path of the line 5 is also located slightly above the sea.

A data acquisition unit 4a floats in the sea 2. The data acquisition unit 4a is provided with a radio antenna 9 for localizing, which radio antenna 9 also forms a gripping portion. As mentioned above, the line 5 has hooks 6 for catching the data acquisition units. The boat 1 moves forward in direction 3, and the ingoing portion 7 of the line 5 forms a front portion of the line that approaches the data acquisition unit 4a.

After a while the ingoing portion 7 of the line 5 hits the data acquisition unit, as illustrated by data acquisition unit 4b. The ingoing portion 7 of the line 5 with its hooks 6 move in direction 19 towards the boat 1, and a hook 6 catches the antenna 9, i.e. the gripping portion, of the data acquisition unit 4b. The ingoing portion 7 of the line 5 thereby forms a catching portion of the line. A lug 25 of the antenna forms a stopper which prevents the hook 6 from sliding off the antenna 9.

The ingoing portion 7 of the line pulls the data acquisition unit towards the boat 1, as illustrated by data acquisition unit 4c. After passing sheave 10d, the line 5 leaves the arm 12 and is pulled alongside and underneath the inclined rod 15d. The data acquisition unit is then lifted out of the sea, as illustrated by data acquisition unit 4d. The line 5 with the attached data acquisition unit passes the driven sheave 10e of the inclined rod 15d, and further passes sheaves 10g and 10i of the base 11, as illustrated by data acquisition unit 4e. The line 5 then passes sheave 10j and is guided to a not illustrated location for releasing the data acquisition unit from its hook. The releasing of the data acquisition units from the hooks may be manual or automatic. After the release of the data acquisition unit, the line 5 is guided back to sheave 10j, further to sheave 10i and 10h and to the driven sheave 10f. The line 5 is continuous, and forms a path or loop on the boat 1. The path on the boat, i.e. the line from the driven sheave 10e to the driven sheave 10f, is pulled by the driven sheave 10f. Fig. 1 illustrates 5 data acquisition units 4a-e. This is for illustration, in a real operation probably fewer, maybe only one, data acquisition units will be present at a time.

Fig. 3 illustrates another embodiment of the apparatus for retrieving data acquisition units floating in the sea. In this embodiment the intermediate part 27 formed by the inclined rod 15d points backwards from the afterdeck 26 of the boat 1. Compared to fig. 1, the beam structure forming the base 11 has a simpler design, and the sheaves 10g,h are omitted. Float 13d is located behind the boat 1. Rod 15c extends backwards oblique to the longitudinal direction of the boat 1, from float 13d to float 13c. Rod 15b extends from float 13c in a direction perpendicular to the longitudinal direction of the boat 1. Rod 15a extends in the same direction as rod 15b. In contrast to the straight arm of fig. 1, the arm of fig. 3 thus has an angle in float 13c. The positioning-ropes 23a-d for the floats 13a-d are attached to the boat 1 in a positioning-unit 24 located on the afterdeck 26. The positioning-unit 24 may include separate winches for each positioning-rope 23a-d for adjusting their length.

Fig. 3 also illustrates a deflector 21 which is connected to the float 13a farthest from the boat by ropes 22. The deflector 21 is a plate or wing moving vertically in the sea, the front of the deflector points in an angle outwards from the direction 3 of forward movement. The water passing the deflector 21 during forward movement of the arm pulls the deflector 21 and thereby float 13a away from the boat and extends the arm.

In other respects, the embodiment of the apparatus for retrieving data acquisition units floating in the sea of fig. 3 is similar to the embodiment of fig. 1. The embodiment of fig. 3 is also operated in the same way as the embodiment of fig. 1.

In the above, line 5 has been described as going along the arm 12 in a horizontal path slightly above the sea 2. By "horizontal path" is meant that the ingoing portion 7 and the outgoing portion 8 of the line 5 (see fig. 1) have the same elevation and form part of a horizontal plane. The plane of the path of the line 5 may, however, have different orientations, e.g. vertical or have an inclined orientation in the sea. The orientation of the path will be the same as the orientation of the sheaves which guides the line. Further the path may have different elevations, and may even be located below the sea surface. The elevation of the path will depend upon the elevation of the sheaves, which in turn depend upon the design of the floats. The portion of the line facing the data acquisition units in the sea during the movement of the line towards the data acquisition units will be the catching portion of the line. What is important, is that the orientation and elevation of the catching portion of the line suit the elevation of the gripping portions of the data acquisition units, and that the hooks are adapted to catch the gripping portions.

The interconnecting structures between the floats described above are called rods. By rods are meant structures with limited ability to withstand torque, transverse forces and bending moments. Since the joints are ball joints, within certain limits no torque, transverse forces or bending moments will be applied to the rods. The ball joints and the rods therefore go well together. The ball joints may be replaced by simpler mechanical connections made by rings, shackles, bolts, rope or similar, which can be made to not apply torque, transverse forces or bending moments to the rods. Such connections may be cheaper than ball joints.

The interconnecting structures between the floats may also be made of beams. By beams is meant structures able to withstand torque, transverse forces and bending moments. In this case there may be used joints which prevent rotation in directions acceptable for applying loads to the beams. Examples of such joints are universal joints which allow rotation in all directions except around the longitudinal axis of the beam, and fork joints which only allow rotation around one axis perpendicular to the longitudinal axis of the beam.

An example of a joint which may be replaced by a fork joint with a horizontal rotation axis is joint 28 which connect the base 11 and the inclined rod 15d, both in fig. 1 and 3. In the embodiment in fig. 1 the inclined rod 15d will then move in a vertical plane perpendicular to the longitudinal direction of the boat 1 and point down into the sea 2 at the side of the boat 1. Varying distances between the base 11 and the sea 2 will be compensated for by rotation of the fork joint 28. In the embodiment in fig. 3, if joint 28 is a fork joint with a horizontal rotation axis, the inclined rod 15d will move in a vertical plane parallel to the longitudinal direction of the boat 1 and point down into the sea 2 behind the boat 1. Varying distances between the base 11 and the sea 2 will be compensated for by rotation of the fork joint 28. The positioning-rope 23d for float 13d can for the embodiments both in fig. 1 and 3 then be dispensed with, which simplifies the apparatus. The inclined rod 15d will have to be made to withstand torque and transverse forces and bending moments from float 13d, i.e. the inclined rod 15d must be a beam.

Whether the interconnecting structures between the floats are called rods or beams is strictly speaking just a matter of terminology. What is important is that the kind of rotation allowed by the joints suits the ability of the interconnecting structures to withstand torque, transverse forces and bending moments, in order to avoid damage to the joints or the interconnecting structures.

The connections between the interconnecting structures and the floats may also be stiff, e.g. welded or bolted, in which case the interconnecting structures must be beams sized to withstand torque, transverse forces and bending moments from the floats in all directions.

Claims

PATENTCLAIMS

1. An apparatus for retrieving data acquisition units (4a-e) floating in a sea (2) and bringing the data acquisition units (4a-e) aboard a vessel (1), comprising:

- a line (5) with hooks (6) for catching the data acquisition units (4a-e);

- guiding means (10a-j) for the line (5), arranged to:

- guide the line (5) in a path substantially at the sea surface, hooks (6) of a catching portion (7) of the line have an elevation suitable for catching the data acquisition units (4a-e);

- guide the line (5) between the sea (2) and the vessel (1);

- guide the line (5) on the vessel (1), to a location for releasing the data acquisition units (4a-e) from the hooks (6);

- a support structure (11, 12, 27) for the guiding means (10a-j); and

- a driver for pulling the line (5).

2. The apparatus of claim 1, wherein the line (5) is a continuous line.

3. The apparatus of claim 1 or 2, wherein the hooks (6) are adapted to hook gripping portions (9) of the data acquisition units (4a-e).

4. The apparatus of any of the preceding claims, wherein the hooks (6) are adapted to hook radio antennas (9) of the data acquisition units (4a-e).

5. The apparatus of any of the preceding claims, wherein the guiding means comprise sheaves (10a-j).

6. The apparatus of any of the preceding claims, wherein the support structure comprises a base (11) for supporting the guiding means (10g-j) on the vessel (1), and an arm (12) with floats (13a-d) for supporting the guiding means (10a-d) in the sea (2).

7. The apparatus of claim 6, wherein the base (11) and the arm (12) are connected by an intermediate part (27) with at least one joint (14).

8. The apparatus of claim 6 or 7, wherein the floats (13a-d) are interconnected by rods (15a-c) or beams.

9. The apparatus of claim 8, wherein the rods (15a-c) or beams are telescopic.

10. The apparatus of claim 8 or 9, wherein the rods (15a-c) or beams are connected to the floats (13a-d) by joints (16).

11. The apparatus of any of the claims 6 to 10, wherein the guiding means (10a-d) of the arm are attached to the floats (13a-d).

12. The apparatus of any of the claims 6 to 11, wherein the arm (12) is provided with at least one deflector (21) for pulling the arm (12) away from the vessel (1) during forward movement of the vessel (1).

13. The apparatus of any of the claims 6 to 12, wherein the position of the arm (12) during forward movement of the vessel (1) is maintained by ropes (23a-d) to the vessel (1).

14. The apparatus of any of the claims 6 to 13, comprising a net suspended from the arm (12), for catching data acquisition units (4a-e) that are missed by or has fallen off the hooks (6).

15. A method for retrieving data acquisition units (4a-e) floating in a sea (2) and bringing the data acquisition units (4a-e) aboard a vessel (1), comprising:

- arranging a line (5) with hooks (6) in a path substantially at the sea surface, hooks (6) of a catching portion (7) of the line have an elevation suitable for catching the data acquisition units (4a-e);

- moving the vessel (1) forward, the catching portion (7) of the line moves towards and hits the data acquisition units (4a-e);

- pulling the line (5), causing the hooks (6) of the catching portion (7) of the line to catch the data acquisition units (4a-e);

- pulling the line (5) with the hooks (6) and the data acquisition units (4a-e) aboard the vessel (1), and

- releasing the data acquisition units (4a-e) from the hooks (6).