Device, system and method for collecting samples from a bed of a waterbody

Abstract

A pin point corer for collecting samples from a seabed of a sea, having a control unit to be positioned on a vessel or similar remote position, a top lift unit, which can be attached to a lifting and lowering unit of a vessel via an cable, such that it can be lifted and lowered relative to the seabed, a corer unit, releasable attached to the top lift unit by a fixation unit and arranged for being at least partly driven into layers of the seabed to collect the samples from there, e.g. when released from the top lift unit, wherein the top lift unit comprises a positioning unit bi-directionally communicating with the control unit for controlling the position of the corer unit. The invention also relates to a respective system and a method for collecting samples by use of such a pin point corer.

Claims

1. A device for collecting samples from a bed of a waterbody, the device comprising: a control unit to be positioned in a remote position; a top lift unit attached to a lifting and lowering unit of a vessel via a cable, such that the top lift unit can be lifted and lowered relative to the bed of the waterbody; a corer unit releasable attached to the top lift unit by a fixation unit and arranged for being at least partly driven into layers of the bed of the waterbody to collect the samples from the bed, when released from the top lift unit; and a depth stabilizer configured to keep the corer unit and top lift unit stable in a vertical direction when they are attached and to level the top lift unit after the corer unit is released from the top lift unit, wherein the top lift unit comprises a positioning unit bi-directionally communicating with the control unit for controlling the position of the corer unit.

2. The device according to claim 1, wherein the corer unit is a free-fall gravity corer unit arranged for being at least partly driven by dead load of the corer unit into layers of the bed of the waterbody and to collect samples from there, when released from the top lift unit.

3. The device according to claim 1, wherein the positioning unit comprises at least one sensor of a group comprising a depth sensor, a motion sensor, an acceleration sensor, a positioning sensor, a camera for environment monitoring, the position unit being arranged for sending sensor data received from the sensor to the control unit.

4. The device according to claim 1, wherein the positioning unit further comprises at least one thruster for at least horizontally positioning the top lift unit.

5. The device according to claim 1, wherein the fixation unit is controllable by the control unit.

6. The device according to claim 1, wherein the fixation unit comprises an actuator for release the corer unit attached to the top lift unit.

7. The device according to claim 1, wherein the fixation unit is arranged for engaging with the corer unit.

8. The device according to claim 7, wherein the fixation unit is arranged to re-attach a released corer unit to the top lift.

9. The device according to claim 1, wherein the corer unit is connected to the top lift unit via a corer wire.

10. The device according to claim 9, wherein in that the corer wire is arranged such that the corer unit can be pulled out of the bed of the waterbody by pulling at the corer wire.

11. The device according to claim 9, wherein the corer wire is attached to a winch arranged such that the corer wire can be spooled out when the corer unit is released from the top lift unit and arranged such that the top lift unit can be pulled to the corer unit when the corer unit) is driven into the layers of the bed of a waterbody and arranged such that the top lift unit can be pulled to the corer unit to engage with the top lift unit by use of the fixation unit.

12. The device of claim 1, wherein the cable is an umbilical wire.

13. A system for collecting samples from a bed of a waterbody comprising: a vessel, comprising a lifting an lowering unit having a cable attached to a device; and the device comprising: a control unit to be positioned in a remote position; a top lift unit attached to a lifting and lowering unit of a vessel via a cable, such that the top lift unit can be lifted and lowered relative to the bed of the waterbody; a corer unit releasable attached to the top lift unit by a fixation unit and arranged for being at least partly driven into layers of the bed of the waterbody to collect the samples from the bed, when released from the top lift unit; a depth stabilizer configured to keep the corer unit and top lift unit stable in a vertical direction when they are attached and to level the top lift unit after the corer unit is released from the top lift unit, and wherein the top lift unit comprises a positioning unit bi-directionally communicating with the control unit for controlling the position of the corer unit.

14. The system of claim 13, wherein the cable is an umbilical wire.

15. A method for collecting samples from a bed of a waterbody by use of a device, the method comprising: lowering a top lift unit and a corer unit of the device in the waterbody by use of a lifting and lowering unit, the top lift unit is connected to via a cable, wherein the corer unit is attached to the top lift unit; positioning the top lift unit in a desired corer release position in a vicinity of the bed of the waterbody by use of a positioning unit bi-directionally communicating with a control unit and keeping the corer unit and top lift unit stable in a vertical direction by using a depth stabilizer; releasing the corer unit from the top lift unit by activating a release mechanism so that it is at least partly driven into layers of the bed of the waterbody while leveling the top lift unit after the corer unit is released from the top lift unit; collecting samples from the layers of the bed of the waterbody; and pulling the corer unit out of the bed of the waterbody and lifting it back to a vessel.

16. The method according to claim 15, wherein the corer release position is a position providing a free-fall height down to the bed of the waterbody for the corer unit when it is released of 3-0.5 meters.

17. The method according to claim 15, further comprising: pulling at the cable in such a way that the top lift unit is lifted thereby pulling at the corer wire; and pulling the corer unit out of the bed of a waterbody.

18. The method according to claim 15, wherein the corer wire is attached to a winch arranged such that the top lift unit can be pulled to the corer unit, the method further comprising: pulling the top lift unit to the corer unit and optionally thereby releasing the cable; attaching the corer unit to the top lift unit; and pulling at the cable in such a way that the top lift unit is lifted, thereby pulling the corer unit out of the bed of a waterbody.

19. The method of claim 15, wherein the cable is an umbilical wire.

Description

(1) These and other features, aspects, and advantages of the apparatus, system and method of the present disclosure, would become better understood from the following description, appended claims, and accompanying drawings, wherein the Figures show:

(2) FIG. 1 to 3 one embodiment of a system for collecting samples from a seabed according to the invention while deploying an embodiment of a pin point corer;

(3) FIG. 4, 5 a detailed view of the pin point corer according to FIG. 1 in an attached and a released state;

(4) FIG. 6 to 8 the system of FIG. 1 while dropping the corer unit, collecting a sample and pulling the pin point corer out of the seabed;

(5) FIG. 9-12 the system of FIG. 1 while recovering the pin point corer;

(6) FIG. 13 a schematic representation of another embodiment of the pin point corer;

(7) FIG. 14 a schematic representation of one embodiment of the top lift unit according to the invention;

(8) FIG. 15, 16 another embodiment of the system for collecting samples from a seabed while deploying another embodiment of the pin point corer;

(9) FIG. 17, 18 a detailed view of the embodiment of the pin point corer according to FIG. 15 in an attached and a released state;

(10) FIG. 19 the system according to FIG. 15 while dropping the corer unit;

(11) FIG. 20 a detailed view of the top lift unit of the embodiment according to FIG. 15 while dropping the corer unit;

(12) FIG. 21 a detailed view of the pin point corer while pulling the top lift unit to the corer unit;

(13) FIG. 22-24 a detailed view of the pin point corer while pulling the top lift unit over the corer unit and the pin point corer out of the seabed;

(14) FIG. 25, 26 the system of FIG. 15 while recovering of the pin point corer;

(15) FIG. 27 a schematic representation of another embodiment of the pin point corer; and

(16) FIG. 28 a schematic representation of another embodiment of the top lift unit.

(17) Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs as read in the context of the description and drawings. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In some instances, detailed descriptions of well-known devices and methods may be omitted so as not to obscure the description of the present systems and methods. Terminology used for describing particular embodiments is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term and/or includes any and all combinations of one or more of the associated listed items. It will be understood that the terms comprises and/or comprising specify the presence of stated features but do not preclude the presence or addition of one or more other features. It will be further understood that when a particular step of a method is referred to as subsequent to another step, it can directly follow said other step or one or more intermediate steps may be carried out before carrying out the particular step, unless specified otherwise. Likewise it will be understood that when a connection between structures or components is described, this connection may be established directly or through intermediate structures or components unless specified otherwise. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control.

(18) The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and/or cross-section illustrations of possibly idealized embodiments and intermediate structures of the invention. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise.

(19) FIGS. 1 to 3 show a side view of one embodiment of a system 100 for collecting samples from a seabed of a sea according to the invention. The system comprises a pin point corer 1 and a vessel 4. The vessel comprises a lifting and lowering unit 8 having an cable 10 where water parts, i.e. inter alia a corer unit 16 and a top lift unit 3 of the pin point corer 1 can be attached to. The cable 10 can be an umbilical wire, and especially allowing for energy supply and/or communication. By use of the lifting and lowering device the water parts of the pin point corer can be lowered and lifted within the sea 104 and in detail to the vicinity of the seabed 102, and especially to a corer release and sample collection position, where samples have to be collected. This can be controlled by the control unit 2 positioned on the vessel or a similar remote position.

(20) The lifting and lowering unit 8 optionally comprises a main winch 9, the cable 10 can be feed by. Further, the lifting and lowering unit 8 optionally comprises an A-frame arrangement 30 and hydraulic activators 32 for lifting and moving the pin point corer 1 attached to the cable. Further provided is a depth stabilizer 12 for stabilizing the depth of the pin point corer during the sample collection process, as will be explained in the following in more detail. For deploying and recovering the pin point corer 1 further a trolley 34 comprising a bucket 36 may be provided as also be explained in the following.

(21) At the beginning of the deployment process, the water parts to be lowered to the seabed of the pin point corer, i.e. inter alia the top lift unit 6 and the corer unit 16, are attached to the lifting an lowering unit 8 in such a way that they can be lifted and moved from the vessel 4 to the open sea and in the water. Here, a trolley 34 and a bucket 36 are provided, wherein the bucket is arranged such that the water parts 6, 16 of the pin point corer 1 can be secured to and lifted by pulling at the cable 10 via the main winch 9. After the water parts 6, 16 of the pin point corer 1 have been lifted out of the bucket 36, the A-frame swivels the water part 6, 16 of the pin point corer 1 outwards in direction to the sea 104 wherein the main winch 9 lowers the pin point corer downwards to the seabed.

(22) As shown in FIG. 3, when a desired corer release position, e.g. providing a desired free fall height h.sub.f is reached, the lowering process stops by stopping the lifting and lowering device 8, e.g. the main winch 9.

(23) In this corer release position the pin point corer 1 is ready for beginning the collecting process.

(24) In a possible embodiment, as for example shown with FIGS. 1 to 3, the pin point corer comprises the top lift unit 6 which can be attached to the lifting and lowering unit 8 of the vessel 4 via the cable 10 such that it can be lifted and lowered relative to the seabed 102.

(25) The pin point corer 1 further comprises the corer unit 16 releasable attached to the top lift unit 6 by a fixation unit 18 (see FIGS. 4 and 5) and arranged for being at least partly driven into layers of the seabed 102 to collect the samples from there (see FIGS. 6 and 7), e. g. when released from the top lift unit 6. By releasing the fixation unit 18, the corer unit 16 can be released from the top lift unit 6 to be driven into the seabed 102.

(26) As e.g. shown with FIGS. 6-8, optionally, the corer unit 16 is provided as a free fall gravity corer unit 16, arranged for being at least partly driven by its death load into layers of the seabed 102 and to collect samples from there, when released from the top lift unit 6. Optionally and especially with this regard the corer unit 16 therefore comprises a corer nozzle 17 and a corer weight 19. In a special embodiment, the corer unit 16 is provided as a piston corer unit comprising a piston 13 as known from the art.

(27) Dependent on the embodiment of the pin point corer 1 and especially of the corer unit 16, the corer release position is a position providing a free fall height h.sub.f down to the seabed 102 of the corer unit 16 when it is released of 3-0.5 m, preferably 2-0.5 m, more preferably 1.5-0.5 m. This free fall height is depicted by reference h.sub.f in FIG. 3.

(28) FIG. 4 to 5 show detailed views of an embodiment of the pin point corer 1 and especially of the water parts 6, 16 of the pin point corer 1 shown with FIGS. 1 to 3.

(29) The pin point corer 1 comprises the top lift unit 6 and the corer unit 16 releasable attached to the top lift unit 6 via the fixation unit 18. The fixation unit 18 can be controlled from a remote position and especially from a control unit arranged at the vessel 4 (see FIG. 1). The fixation unit may comprise a hydrostatic actuator for releasing the corer unit 16 attached to the top lift unit and especially under the control of the control unit 2. This hydrostatic actuator might comprise a solenoid valve.

(30) In a special embodiment, the fixation unit 18 be provided that not only engaging with and releasing of the corer unit 16 is possible, but also (re-)engaging of a corer unit which has been released from the top lift unit before, i. e. for collecting a sample.

(31) As can be seen with FIGS. 4 and 5, the top lift unit comprises a positioning unit 20 which is arranged for bi-directionally communication with the control unit 2 for controlling the position of the corer unit.

(32) For such positioning the positioning unit 20 optionally comprises at least one sensor of the group of the multiple available sensors 22, 24. Such a sensor 22 can for example be a depth sensor, a motion sensor, an acceleration sensor or a positioning sensor. All these sensors are optionally provided at the top lift unit as shown with FIGS. 4 and 5. A further sensor can be provided, i. e. a camera 24, e. g. for environment monitoring. The sensor 22, 24 can also be provided as a CTD device for gathering conductivity, temperature and depths of the top lift unit. In principle, the position unit 20 is optionally arranged for sending sensor data received from the sensor 22,24 to the control unit and further optionally for receiving data from the control unit 2. Such communication can be arranged via the cable 10 and a respective wired signal connection or any other possible data communication between the vessel 4 and its control unit 2 and the water parts of the pin point corer especially when it is under water.

(33) Here of course any other kind of communication, e.g. wireless communication via a radio communication, optical communication, acoustic communication etc. is applicable.

(34) With this embodiment, the top lift unit optionally comprises two high definition cameras 24 for environment monitoring and especially for monitoring the position of the top lift unit under water. Further, respective lights may be provided (not shown, but here optionally provided). The cameras may further serve for control of the corer unit 16 and especially whether dropping and driving the corer unit into the seabed 102 was successful. Optionally the sensors 22, 24, and especially the cameras 24 can be used for detecting and searching desired sample collecting positions for collecting samples. As explained before, data gathered from the sensors is provided via data communication to the control unit 2 at the vessel 4.

(35) As can be further seen with FIGS. 4 and 5, the top lift unit 16 comprises at least one thruster 26 for at least horizontal control, and especially navigation of the top lift 6 unit. By activating the thrusters 26 horizontal navigation of the top lift unit is possible, wherein the position of the top lift unit 6 can be controlled by the sensor 22,24 and here especially by the camera 24. Of course, other sensors can be used for position detection and control.

(36) For activating the thrusters 26 a power supply and especially battery packs 40 may be provided. Of course, also a wired power supply from the vessel 4 etc. can be provided.

(37) As can be again seen with FIGS. 4 and 5, the top lift unit comprises an open and lightweight construction and especially a frame structure, and optionally of a lattice structure, acting as a carrier element for the respective equipment of the top lift unit, e.g. the sensors, thrusters, batteries etc.

(38) Further, a corer wire 14 may be provided connecting the top lift unit 6 with the corer unit 16.

(39) As explained the pin point corer 1 is arranged for detecting a collecting position via its sensors 22, 24 and especially via the cameras 24. Further, sensors may be provided for depths and acceleration detection and control. Navigation of the water parts of the pin point corer is possible via the lifting and lowering device of the vessel and via the thrusters to find the desired collection position. After this position is found, releasing of the corer unit 16 is possible controlled by the control unit 2 arranged at the vessel as explained in the following.

(40) After positioning the top lift unit 6 such that the corer unit 16 is arranged in a desired position, e.g. with a free fall height h.sub.f from the seabed as mentioned before, the fixation unit 16 (see FIGS. 4 and 5) can be released and opened, respectively, to release the corer unit 16. As can be seen with FIGS. 6 and 7, the corer unit 16 can be arranged such that it drops from the top lift unit 6 thereby being driven into the seabed 102, especially with its corer nozzle 17. With this embodiment the corer unit 16 optionally is a piston corer comprising the piston 13. Any other known corer unit form the art may also be provided. As can be seen with FIG. 7 the piston 13 stays at seabed level wherein the corer nozzle 17 drops over the piston 13.

(41) While dropping the corer unit 16 and driving it into the seabed 102, the corer wire 14 is pulled out. It becomes clear that the length of the corer wire 14 preferably should to be slightly longer than the closest distance of the top unit 6 to the corer unit 16 driven in the seabed 102.

(42) To ensure that after releasing the corer unit 16 from the top lift unit 6 the top lift unit 6 is not flipped upwards in an uncontrolled manner due to loss of weight, the depth stabilizer 12 may be provided on the vessel 4. This depth stabilizer 12 is optionally part of the lifting and lowering unit and allows levelling of the top lift unit in a very quick and reliable manner. Control of levelling of the top lift unit 6 can further be enhanced by use of the sensors 22 sending information with regard to the position and acceleration/movement of the top lift unit 6 to the control unit. The control unit then may be arranged to control the lifting and lowering unit and especially the depth stabilizer 12 and/or the main winch 9.

(43) At the target depths, e. g. the corer release position, the depth stabilizer may keep the pin point corer stable in vertical direction. It may be applicable that the main winch 9 is adjusted when the stabilizer comes out of range.

(44) After the sample has been collected from the seabed 102, the corer unit has to be pulled out of the seabed. In one embodiment the pin point corer 1 may be arranged such that the corer unit 16 can be pulled out of the seabed by pulling at the cable 10 in such a way that the top lift unit is lifted thereby pulling at the corer wire 14 and pulling the corer unit 16 out of the seabed 102. This is for example shown with FIG. 8.

(45) FIGS. 9 and 10 show the embodiment of the system of FIG. 1 while recovering of the pin point corer 1 and its top lift unit 6 and corer unit 16, respectively. As explained before, here the corer unit is attached to the top lift unit 6 by the corer wire 14.

(46) As can be seen with FIGS. 7 to 10, the corer wire 14 comprises a peer socket 42 allowing detaching of the corer unit 16 from the top lift unit 6. For recovering the water parts 6, 16 of the pin point corer by use of this peer socket 42 the before-mentioned bucket or a similar fixation device 36 is arranged such that the peer socket 42 can be temporarily secured thereto. After securing the peer socket 42 to the bucket 36, the top lift unit 6 can be detached and stored to the vessel 4. This is for example possible by use of the A-frame 30 and swivelling each in direction of the vessel.

(47) The corer unit 16 secured to the bucket 36 via the peer socket 42 can be recovered to the vessel for example by use of a lifting and lowering device, i. e. the main winch 9 or another sub-winch 15 and a respective wire 11 or similar rope. With this embodiment the core unit 16 is arranged to be secured to the bucket 36 wherein the bucket can then be swivelled in direction to the vessel to secure the corer unit 16 to the vessel. For moving the corer unit 16 to the vessel a trolley 34 can be provided which is optionally also moveable by a lifting and lowering device and especially by a sub-winch 15.

(48) FIG. 13 represents a schematic visualization of an embodiment of the pin point corer 1 showing respective assemblies and modules provided.

(49) The same applies for FIG. 14 showing an embodiment of the top lift unit and its possible assemblies and modules.

(50) FIGS. 15 and 16 show another embodiment of the system 100 comprising another embodiment of the pin point corer 1. In principle, the system is similar to the system explained before, also comprising a vessel 4, a lifting and lowering device 8 having a main winch 9 and optionally a depth stabilizer 12. Further, an A-frame 30 or similar holding and swivelling device with its respective assemblies is provided. For redundancy reasons to the before-mentioned explanation is referred.

(51) With regard to FIGS. 17 and 18 a further embodiment of the pin point corer 1 is shown again comprising a top lift unit 6 and a corer unit 16 attachable to the top lift unit 6 via a fixation unit 18. The fixation unit allows releasing of the corer unit 16 such that the corer unit can be driven into the seabed 102 (e. g. FIG. 19). It however also allows (re-)connecting a corer unit 16 to the top lift unit 6, e.g. when the corer unit 16 has been released before. This is going to be explained in the following in more detail.

(52) The top lift unit 6 of the embodiment according to FIGS. 17 and 18 is constructed almost identical to the top lift unit 6 as explained before and especially with regard to the embodiment of FIG. 1. Further the top lift unit also comprises a winch 21 or similar coiling unit.

(53) With this embodiment the winch 21 is attached to the top lift unit 6. The winch 21 provides a respective length of the corer wire 14 which can be spooled out when the corer unit 6 is released from the top lift unit 6. This arrangement is shown with FIGS. 17 and 18. The length of the corer wire 14 is optionally provided slightly longer than resulting from the free fall height required for driving the corer unit 6 to the seabed 102.

(54) As can be seen with FIGS. 17 and 18, the top lift unit 6 also comprises a position indicator 28 indicating the position of the corer unit 16 relative to the top lift unit 6. In a special embodiment, the position indicator 28 indicates whether the corer unit 6 is in the attached position at the top lift unit 6 or not. In general, the position indicator may be a sensor of the positioning unit 20. Also with this position indicator distance measurement, movement measurement etc. may be possible, dependent on the embodiment of the position indicator.

(55) As shown with FIG. 19, after reaching the desired collecting position and especially at the corer release position, e.g. having a desired free fall height h.sub.f for the corer unit 16, i.e. the corer unit 16 is released from the top lift unit 6 thereby falling in direction of the seabed 102.

(56) After releasing the corer unit 16 the corer nozzle 17 is driven into the layers of the seabed 102 thereby collecting samples. For preventing that the corer wire 14 connecting the top lift unit 6 and the corer unit 16 is being bent and twisted, optionally a swivel joint is provided and optionally provided at the winch 15, as shown with FIG. 20.

(57) Preparations for pulling the corer unit out of the seabed 102 are shown with FIG. 21-24.

(58) For recovering the corer unit 16 with this embodiment, the winch 21 is activated thereby pulling the top lift unit 6 over and in direction to the corer unit 16 as can be seen with FIGS. 21 to 24. Here it may probably be necessary to release the cable 10 especially by activating the lifting and lowering device 8 on the vessel 4 or the depth stabilizer 12. By use of the position indicator 28 (see FIG. 21) positioning of the corer unit 16 with regard to the top lift unit 6 is controlled. Optionally, it may be provided that as soon as the position indicator indicates that the corer unit 16 is in an attachment position, the fixation unit 18 may be activated to attach and especially lock the corer unit 16 to the top lift unit 6.

(59) With other words, with the embodiment shown the corer wire is optionally attached to the winch 15 which is arranged such that the corer wire 14 can be spooled out when the corer unit 16 is released from the top lift unit 6. Further, it may hold, that the corer wirer 14 and the winch 15 are arranged such that the top lift unit 6 can be pulled to the corer unit 16, e. g. when the corer unit is driven into the layers of the seabed 102 and/or that the winch and the corer wire are arranged such that the top lift unit 6 can be pulled to the corer wire unit 16 to engage and especially re-engage with the top lift unit by use of the fixation unit 18.

(60) As soon as the corer unit 16 is attached to the top lift unit 6 the two units can be pulled in direction to the vessel 4 thereby pulling the corer unit out of the seabed 102.

(61) Recovery of the water parts of the pin point corer 1 and its respective top lift unit 6 and corer unit 16 is shown with FIGS. 25 and 26.

(62) As the corer unit 16 is already attached to the top lift unit 6, the water parts of the pin point corer can be at least temporarily secured to the bucket 36 and moved to the vessel by the trolley 34. Optionally, it is possible to detach the top lift unit 6 from the corer unit 16 while the corer unit 16 is secured to the bucket 36 for storing the two units individually on the vessel 4.

(63) FIG. 27 represents a schematic visualization of an embodiment of the pin point corer 1 showing respective assemblies and modules provided.

(64) The same applies for FIG. 28 showing an embodiment of the top lift unit and its possible assemblies and modules.

(65) In the foregoing specification, the invention has been described with reference to a specific embodiment of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention as set forth in the appended claims. It has to be mentioned that all the features mentioned and especially the features mentioned in the claims could be provided with an embodiment of the invention in combination or on their own. The combination of features as brought forward with the above embodiments is not necessarily required.

(66) However, other modifications, variations and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

(67) In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

(68) Finally, the above-discussion is intended to be merely illustrative of the present systems and/or methods and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments.

REFERENCE SIGNS

(69) 1 pin point corer 2 control unit 4 vessel 6 top lift unit 8 lifting and lowering unit 9 winch 10 cable 11 wire 12 depth stabilizer 13 piston 14 corer wire 15 winch 16 corer unit 17 corer nozzle 18 fixation unit 19 corer weight 20 positioning unit 21 winch 22 Depth-, acceleration-, moving-, positioning-sensor, CTB 24 camera 26 thruster 28 position indicator 30 A-frame 32 hydraulic activator 34 trolley 36 bucket 38 sub winch 40 battery pack/power supply 42 pear socket 44 swivel joint 100 system 102 seabed 104 sea h.sub.f freefall height