JP2005039982A - Submarine excavator improved in excavation efficiency - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a submarine excavator which can improve an excavation efficiency, which can bury a pipe or a cable linearly parallel to a sea level, which can flexibly and accurately perform an excavation operation, and which can operate the excavator directly by a diver in the sea. <P>SOLUTION: The marine excavator includes a groove formed to bury the pipe or the cable under the seabed. The marine excavator further includes a support 7 having two flat plates disposed so as to be opposed via a predetermined distance so that two plates of substantially trapezoidal shape which becomes larger gradually as its height is directed rearward, in such a manner that lower ends of the two flat plates for constituting the support are aligned in parallel with a moving direction of the marine excavator. The marine excavator also includes a nozzle for injecting a high pressure water stream for excavating the seabed toward a direction between a direction opposite to the moving direction of the marine excavator and a direction of the seabed direction, a water pipe and an underwater pump 2 for supplying a high pressure water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a submarine excavator with improved excavation efficiency, which is used for the purpose of burying pipes or cables in the seabed.

Conventionally, in order to embed a pipe such as a water intake pipe, a water supply pipe or an oil feed pipe, or a cable such as a communication cable or a power cable, a groove for burying pipes or cables by jetting high-pressure water from a number of nozzles. 2. Description of the Related Art A water jet type seabed excavation and burial machine that is digging is known (see, for example, Patent Documents 1 and 2).
JP-A-6-141430 JP 2001-112136 A

  However, in the conventional water jet type seabed excavation / burying machine, gaps are generated between the numerous nozzles and the seabed, and a part of the high-pressure water flow discharged from the nozzles is used for the seabed excavation. There is a problem that excavation efficiency deteriorates because it flows into seawater without being used.

  Moreover, in the conventional water jet type seabed excavation and burial machine, since the high pressure water from the many nozzles is always discharged from a certain height position, the excavation depth by the high pressure water is always relative to the sea bottom. As a result of the pipe or cable being buried at a certain depth from the undulating sea bottom, the pipe or cable is buried in a vertically curved state corresponding to the sea bottom undulation. There was a problem of being.

  Also, in conventional water jet type submarine excavation and burial machines, hydraulic pressure was sent from the ship with a hose to drive the submarine excavation and burial machines, so that excavation and other operations should be performed flexibly and with high precision. There was a problem that it was not possible.

  Furthermore, in conventional water jet type submarine excavation and burial machines, an operation panel for performing excavation operations and the like is provided only on the ship, and images from a video camera attached to the submarine excavation and burial machine are viewed. However, since it was operated only on the ship, there was a problem that underwater divers could not directly operate the submarine excavation and burial machine.

  The present invention has been made paying attention to such problems of the prior art, and can greatly improve the excavation efficiency compared to the prior art, and embed pipes or cables in a straight line parallel to the seawater surface. It is an object of the present invention to provide a submarine excavator that can perform excavation operation flexibly and with high accuracy, and that allows divers in the sea to directly operate the excavator.

  The seabed excavator according to the present invention for solving the problems of the prior art is used to gradually form a groove on the seabed for embedding pipes or cables in the seabed in a predetermined direction. A submarine excavator that is provided along a direction of movement of the submarine excavator, and a high-pressure water flow for excavating the seabed is directed toward the seabed or in a direction opposite to the direction of movement of the submarine excavator. A nozzle for jetting in a direction between the seabed direction and a support part configured to be movable in a direction close to the seabed or away from the seabed with respect to the seabed excavator body, It consists of a flat plate arranged in parallel with the moving direction of the submarine excavator body, and a lower end portion of the support portion provided with a plurality of the nozzles, and a high-pressure water flow for excavating the sea bottom from the nozzles. When said support part Record the terrain data such as undulations on the bottom of the seabed where pipes or cables are to be embedded in association with the bottom coordinate data of the seabed, and push down parts for pushing down a predetermined distance from the predetermined height toward the seabed. A submarine excavator on the basis of the current position data from the current position estimation unit and the topographic data from the topographic database; The distance by which the support portion should be pushed down by the push-down portion is determined so that the excavation depth of the seabed by the high-pressure water flow from the nozzle at the current position is always a substantially constant depth from the sea level regardless of the undulations on the seabed. A push-down distance calculating means, and when the high-pressure water flow for excavating the sea bottom is ejected from the nozzle, the push-down A push-down control unit for controlling the push-down unit based on an output from the separation calculation unit and adjusting the push-down distance of the support unit toward the seabed by the push-down unit. To do.

  Further, in the submarine excavator with improved excavation efficiency according to the present invention, a hydraulic motor and a hydraulic tank are arranged in the vicinity of the support portion, and electric power and a control signal are transmitted to the hydraulic motor from a marine ship via a cable. It is desirable to do so.

  Furthermore, in the submarine excavator with improved excavation efficiency according to the present invention, the two flat plates constituting the support portion are arranged to face each other through a distance larger than the diameter of the pipe or cable to be embedded. It is desirable that a pipe or a cable to be embedded in the space between the two flat plates is arranged at the time of seabed excavation.

  As described above, in the present invention, “the support portion provided with the nozzle is configured to be movable in the vertical direction (direction approaching or moving away from the seabed), and further, the seabed is moved from the nozzle. When a high-pressure water flow for digging is being ejected (that is, during excavation work on the seabed), the support portion provided with the plurality of nozzles is pushed down from a predetermined height position toward the seabed by a predetermined distance. ”(See the pressing cylinder 9 in FIG. 5)”. Therefore, according to the present invention, “a part of the high-pressure water ejected from the nozzle as in the prior art does not escape from the gap between the nozzle and the sea bottom without being used for excavation. It will be possible to greatly improve the excavation efficiency. ”

  Further, in the present invention, “a push-down control means for controlling the push-down portion so that the push-down distance of the support portion by the push-down portion toward the sea bottom can be adjusted to an arbitrary distance” is provided. . Therefore, according to the present invention, it is possible to obtain a special effect that “the depth of excavation from the sea bottom can be finely adjusted according to the situation such as the undulation of the sea bottom”.

  Further, in the present invention, based on the topographical data of the seabed corresponding to the current estimated position of the seabed excavator, the “depth of excavation from the seabed” to be excavated by the seabed excavator (for example, constant from the sea level) The excavation depth that is parallel to the sea surface is maintained, and further, the push-down distance of the support portion by the push-down portion (such as the press cylinder 9 in FIG. 4) for realizing the obtained excavation depth is obtained. The push-down portion is controlled and adjusted so as to realize the push-down distance. Therefore, according to the present invention, it is possible to embed a cable or a pipe at a depth position (a depth position parallel to the seawater surface) at a certain distance from the seawater surface. That is, in the past, cables or pipes were buried at a certain depth from the bottom of the sea (a position parallel to the bottom of the sea), so that the cables or pipes correspond to the undulations on the bottom of the sea. There was a problem of being embedded in a curved state (see FIG. 8A described later. In addition, if a cable or a pipe is curved and embedded in a vertical direction, for example, a siphon method is used. When trying to take deep ocean water into the sea, there are problems such as air bubbles in the pipe expanding above the pipe and expanding into an air layer that blocks the flow of deep ocean water was there). On the other hand, in the present invention, it becomes possible to embed a cable or a pipe at a depth position (a depth position parallel to the seawater surface) at a certain distance from the seawater surface regardless of the undulations of the seafloor ( (See FIG. 8B, which will be described later), the conventional problems as described above can be avoided.

  In the present invention, the submarine excavator is provided with a hydraulic unit (including a hydraulic tank, a hydraulic motor, a hydraulic pump, etc.), and this hydraulic unit is controlled and driven by electric power and a control signal from the ship. Compared to the conventional case where hydraulic pressure is supplied from the hydraulic tank on the ship to the sea floor by the hydraulic hose, the transfer distance of hydraulic pressure from the hydraulic tank to the hydraulic motor, etc. is significantly shortened, and the driving device such as hydraulic motor The start-up speed and operation accuracy of can be improved.

  The best mode for carrying out the present invention is a mode as described in Example 1 below.

  Hereinafter, a submarine excavation and burial machine according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a submarine excavation and burial machine according to the present embodiment. In FIG. 1, illustration of the traveling wheels (see reference numeral 5 in FIG. 3) and the like is omitted. In FIG. 1, 1 is a sled section for preventing a submarine excavating and burying machine from sinking into a soft ground on the seabed, 2 is a submersible pump, 3 is for taking in a cable or pipe placed on the seabed. It is a capturing part.

  FIG. 2 is a diagram for explaining the configuration of the capturing unit 3. The intake section 3 first surrounds the cable or pipe 4 placed on the sea bottom from both sides (see FIG. 2A), and then scoops the lower surface of the cable or pipe 4 from both sides. Then, it takes it into itself (see FIG. 2B). In this state, the seabed excavation and burial machine travels and moves on the seabed at a predetermined speed while performing seabed excavation work described later.

  Next, FIG. 3 is a plan view showing the submarine excavation / burying machine of the present embodiment. In FIG. 3, reference numeral 5 denotes a traveling wheel for the seabed excavation / burying machine of the first embodiment, and 6 denotes a hydraulic unit for driving the submersible pump 2 and the like. The seabed excavation / embedding machine of this embodiment travels on the seabed at a predetermined speed by the wheels 5 while excavating the seabed and burying cables or pipes.

  Next, FIG. 4 is a side view showing the submarine excavation / burying machine of the present embodiment. The seabed excavation / burying machine shown in FIG. 4 is moved by the wheel 5 in the direction of arrow α in the figure. In FIG. 4, reference numeral 7 denotes a support portion made of a stainless steel flat plate (two pieces) having a substantially trapezoidal (substantially fan-shaped) side surface provided in parallel with the moving direction of the seabed excavation / burying machine, and 8 denotes a support portion 7. Numerous nozzles arranged along the moving direction (arrow α direction) at the lower end of each flat plate, 9 is a pressing cylinder (the hydraulic unit for pushing down the support portion 7 in the seabed direction (arrow β direction in the figure) 10 is a frame for fixing the wheel 5, the hydraulic unit 6, the support portion 7, the pressing cylinder 9, and the like.

  In FIG. 4, the right end portion (the lower end portion of the portion having the largest trapezoidal side surface height) A of the lower end portion (the portion provided with the nozzle 8) of the support portion 7 and the wheel 5. The line connecting the lower end B of the accord with the sea bottom (ground surface).

  In FIG. 4, the support portion 7 is connected to the frame 10 by a connection portion (hinge portion) 11. The support portion 7 is connected to the frame 10 so as to be rotatable in the arrow γ direction with the connection portion 11 as a fulcrum (see also FIG. 5). In addition, an underwater television camera 12 is provided at the left end portion 10a of the frame 10 for capturing a surrounding image and sending the image to a monitor device of a ship at sea.

  In FIG. 4, the hydraulic unit 6 includes a hydraulic motor, a hydraulic pump, a hydraulic tank, and the like that are controlled and driven by electric power and control signals sent from a cable from the ship. The hydraulic unit 6 drives the submersible pump 2, the wheel 5, the pressing cylinder 9, and the like fixed to the frame 10. Although not shown, a submarine operation panel is provided at a position near the hydraulic unit 6 on the frame 10 so that divers in the sea directly operate the hydraulic unit 6.

  FIG. 6 is a diagram for explaining the configuration of the support portion 7 of FIG. 4 in more detail. 6A is a view when the support portion 7 is viewed from the back side of the present embodiment, FIG. 6B is a view showing a side surface of the support portion 7, and FIG. 6C is a view illustrating the support portion 7 according to the present embodiment. It is a figure when it sees from the front (running direction) of an example. As shown in FIGS. 6A and 6C, the support portion 7 is composed of two substantially trapezoidal (substantially fan-shaped) stainless steel flat plates. The two flat plates are arranged to face each other at a position separated by a predetermined distance (a distance slightly larger than the diameter of the cable or pipe to be embedded (for example, 50 cm)).

  In FIG. 6, 13 is a water distribution pipe attached to the support portion 7 in a state where it is connected by a submersible pump 2 (see FIG. 3) and a bellows type hose (not shown), and 14 is a plurality of water distribution pipes 13. It is a water distribution branch attached to the support part 7 in order to connect the nozzle 8 of this (it mentions later in detail).

  The two support portions 7 are for supporting the water distribution pipe 13, the water distribution branch pipe 14, the nozzle 8, and the like. As shown in FIGS. 6A and 6C, the two support portions 7 are formed in a substantially inverted U shape including the water distribution pipe 13 and the water distribution branch pipe 14. Note that the broken line indicated by reference numeral 7 in FIG. 1 indicates the approximate position of the substantially inverted U-shaped support portion 7.

  Next, FIG. 7 is a block diagram for explaining a part of the electrical configuration of the present embodiment. In FIG. 7, 21 is a GPS (Global Positioning System) receiver provided on the ship, and 22 is a terrain database for recording terrain data including undulations on the bottom of the seabed of the cable or pipe planned to be buried. The terrain database 23 composed of a hard disk or the like provided on the ship is used to control a subsea hydraulic motor 6b (and a pressing cylinder 9), which will be described later, based on data from the GPS receiver 21 and the terrain database 22. A personal computer (provided on board) having a push-down control function for outputting a control signal, 25 is an onboard operating panel (provided near the personal computer 23 on board) for operating the hydraulic motor 6b and the like. An onboard control panel for the crew on board to operate while watching the video from the underwater TV camera 12 of FIG. , 25 is provided on board, a control signal transmitting unit, for a control signal from the personal computer 23 or onboard control panel 24 transmits through the control signal cable 26 to the seabed excavation and buried machine side.

  In the terrain database 22, a cable acquired using a side scan sonar for collecting terrain data such as undulations of the seabed and a GPS receiver 21 on the ship before the cable or pipe is buried. Topographic data including the undulations of the bottom of the sea at the site where the pipe is to be buried is recorded in association with the position coordinate data.

  Next, a push-down control function as a part of the function by the personal computer 23 will be described. In this function, when the current position data of the ship from the GPS receiver 21 is received, the current position of the ship is estimated as the current position of the seabed excavation and burial machine. Then, the topographical data of the seabed corresponding to the estimated current position of the seabed excavation / burying machine is called from the topographic database 22. Then, based on the terrain data corresponding to the current position called from the terrain database 22, the “desirable excavation depth” when the seabed excavating / burying machine excavates the seabed is obtained by a predetermined program. A push-down distance of the support portion 7 of the pressing cylinder 9 necessary for realizing the “digging depth that should be” and a control signal to the hydraulic motor 6b for realizing the push-down distance are generated. The generated control signal is transmitted from the control signal transmission unit 25 to the hydraulic motor 6b of the seabed excavation / burying machine on the seabed through the control signal cable 26.

  In FIG. 7, 6a is a hydraulic tank built in the hydraulic unit 6 of the seabed excavation / burial machine, 6b is a hydraulic motor built in the hydraulic unit 6 of the seabed excavation / burial machine, and 9 is driven by the hydraulic motor 6b. And a pressing cylinder 27 for pushing down the support portion 7 by a predetermined distance in the direction of the seabed, and 27 is in the vicinity of the hydraulic unit 6 of the submarine excavation / burying machine (frame) so that the divers in the sea directly operate the hydraulic motor 6b and the like. 10) is a submarine operation panel. It should be noted that the submarine operation panel 27 of FIG. 7 is not shown in FIG.

  The submarine operation panel 27 and the onboard operation panel 24 of FIG. 7 not only operate the hydraulic motor 6b for driving the pressing cylinder 9 of FIG. 7, but also the hydraulic pressure for driving the submersible pump 2 of FIG. It is configured to be used for operating a motor (not shown in FIG. 7) and the like. As described above, the submarine operation panel 27 of FIG. 7 is configured so that an underwater diver can directly operate the submarine operation panel 27 to operate the hydraulic motor 6b, the submersible pump 2, and the like.

  Next, the operation of this embodiment will be described mainly with reference to FIGS. As described above with reference to FIG. 7, when using this embodiment, the planned route to be buried using the GPS receiver 21 and the side scan sonar while cruising on the sea of the route to be buried by cable or pipe in advance. Is recorded in the terrain database 22 in association with the position coordinate data.

  Thereafter, when actually embedding the cable or pipe, the cable or pipe is first placed on the seabed by a ship. Then, the submarine excavation / burying machine of this embodiment is placed on the cable or pipe while towing the ship, and the cable or pipe is taken in by the take-in part 3 as shown in FIG.

  Next, the submersible pump 2 is driven to send the seawater to the plurality of nozzles 8 through the water distribution pipes 13 and the water distribution branch pipes 14 at a pressure set in advance for each. High pressure water is ejected from each nozzle 8 in a “direction opposite to the traveling direction of the seabed excavation / burying machine by the wheel 5 (rearward direction) and the middle direction between the seabed direction”. This ejection is performed in parallel with the traveling of the seabed excavation / buried machine by the wheels 5. At the same time, the pressing cylinder 9 pushes down the upper end portion of the support portion 7 in the seabed direction (arrow β direction) as shown in FIG. When the high-pressure water is discharged from the nozzle 8 to the sea bottom by this depression, a part of the high-pressure water from the nozzle 8 does not escape from the gap between the nozzle and the sea bottom. Can be excavated very efficiently.

  At the same time as the excavation of the bottom of the sea by such high-pressure water jetting, the cable or pipe taken in by the take-in unit 3 (see FIG. 1) is connected to the seabed excavation and burying machine by the wheels 5. As the vehicle travels, it is placed in the groove formed by the excavation. Further, since the seabed excavation / burying machine travels at a predetermined speed in parallel with such an operation, the sediment on the seabed excavated by the high-pressure water from the nozzle 8 is the traveling direction of the seabed excavation / burying machine. The cable or pipe is continuously buried by being rolled up in the opposite direction (backward direction) and the earth and sand that has been wound up being deposited on the cable or pipe placed in the groove. It will be done.

  As described above, in this embodiment, when high-pressure water is ejected from the nozzle 8, the pressing cylinder 9 pushes down the support portion 7 in the seabed direction (β direction in FIG. 5). When there is no such “pressing down of the support portion 7 by the pressing cylinder 9”, even if high-pressure water is ejected from the nozzle 8, a part of the high-pressure water is not used for excavation and the nozzle 8 and the seabed. Excavation efficiency deteriorates because it escapes into the sea from the gap between the surface. In order to prevent such inconvenience, in this embodiment, as described above, the support portion 7 is pushed down by the pressing cylinder 9 so that no gap is formed between the nozzle 8 and the sea bottom. Therefore, in this embodiment, the excavation efficiency can be greatly improved as compared with the conventional case.

  Further, in this embodiment, as described above with reference to FIG. 7, the personal computer 23 on the ship estimates the current position of the submarine excavation / embedding machine based on the data from the GPS receiver 21 on the ship, "Drilling depth from the bottom of the sea" to be excavated by the seabed excavation and burial machine based on the corresponding topographic data of the seabed (for example, to embed a cable or pipe at a certain distance from the sea level, The depth of excavation from the bottom of the sea), and the pressing distance of the support portion 7 by the pressing cylinder 9 for realizing the calculated excavation depth is determined, and the pressing cylinder 9 is driven by this pressing distance. The control signal is transmitted to the hydraulic motor 6b on the seabed via the control signal transmission unit 25.

  Thereby, in a present Example, the pressing-down distance of the support part 7 by the said press cylinder 9 can be changed and adjusted arbitrarily, and the excavation depth from the sea bottom by the high pressure water from the said nozzle can be adjusted arbitrarily. It becomes like this. For example, in this embodiment, by adjusting the pressing distance of the pressing cylinder 9, as shown in FIG. 5, the illustrated right lower end portion of the support portion 7 is pushed down from the position A to the position A ′ in FIG. It is possible to excavate to the position of A ′, or it is possible to excavate to the position of A2 ″ by pushing down the support portion 7 to the position of A ″.

  That is, in this embodiment, it is possible to embed a cable or a pipe at a depth position (a depth position parallel to the seawater surface) at a certain distance from the seawater surface, which has been difficult in the past. That is, the conventional seabed excavation and burial machine cannot perform excavation according to the topography including the undulations of the seabed, and as shown in FIG. 8 (a), a certain distance from the seabed M (not the seawater level H). The cable or pipe must be buried at a depth position L (depth position parallel to the sea bottom M). However, since the actual sea bottom has various undulations, when a cable or pipe is embedded in parallel with the sea bottom M, the cable or pipe is greatly curved in the same manner as the undulation of the sea bottom M (FIG. 8A). There is a problem that it is buried in (see L). In contrast, in the present embodiment, as described above, a depth position (depth position parallel to the seawater surface H) L ′ (a figure parallel to the seawater surface H) from the seawater surface H regardless of the undulations of the seabed M. 8 (b)), it is possible to embed a cable or a pipe. Therefore, in this embodiment, as shown in FIG. 8 (b), even if the sea bottom M is undulated, the cable or pipe is linearly parallel to the sea water surface H (see FIG. 8 (b)). It becomes possible to embed it in the reference L ′).

  Further, in the present embodiment, as described above with reference to FIG. 7, the submarine excavation / burying machine is provided with a hydraulic unit (including a hydraulic tank, a hydraulic pump, a hydraulic motor, etc.) and this hydraulic pressure is controlled by electric power and a control signal from the ship. Since the unit 6 is controlled and driven, the hydraulic pressure transfer distance from the hydraulic tank to the hydraulic motor or the like is smaller than the conventional case where the hydraulic pressure is supplied from the hydraulic tank on the ship to the sea floor by the hydraulic hose. As a result, the start-up speed and operation accuracy of a drive unit such as a hydraulic motor can be improved.

  Furthermore, in this embodiment, not only the operation panel for operating the hydraulic unit 6 and the submersible pump 2 on the ship is provided, but also the hydraulic unit 6 and the submersible pump 2 can be operated on the side of the submarine excavation / burying machine. Since the operation panel is provided, the crew not only operates the hydraulic unit 6 and the submersible pump 2 from the ship as usual, but also divers in the sea directly operate the hydraulic unit 6 and the submersible pump 2 and the like. It becomes possible.

The front view which shows the seabed excavation and burial machine by the Example of this invention. The figure for demonstrating operation | movement of the acquisition part of FIG. The top view of the seabed excavation and burial machine by a present Example. The side view of the seabed excavation and burial machine by a present Example. The figure for demonstrating operation | movement of the seabed excavation and burial machine by a present Example. The figure for demonstrating the structure of the support part of the seabed excavation and burial machine by a present Example. The block diagram which shows a part of electrical structure of the seabed excavation and burial machine by a present Example. The figure for demonstrating operation | movement of the seabed excavation and burial machine by a present Example.

Explanation of symbols

2 Submersible pump 4 Pipe 5 Wheel 6 Hydraulic unit 6 b Hydraulic motor 7 Support portion 7 a Left end portion 7 b of support portion Right end portion 8 of support portion Nozzle 9 Press cylinder 10 Frame 11 Connection portion 12 Underwater television camera 13 Distribution pipe 14 Distribution branch pipe 21 GPS Receiver 22 Topographic database 23 Personal computer 24 Onboard control panel 25 Control signal transmitter 26 Control signal cable 27 Submarine control panel H Sea level L Embedment position M Sea bottom

Claims (4)

A seabed excavator used for gradually forming a groove on the bottom of the sea for embedding pipes or cables in the seabed in a predetermined direction.
Along the direction of movement of the seabed excavator, the high-pressure water flow for excavating the seabed is directed toward the seabed or in a direction opposite to the direction of movement of the seabed excavator and the direction of the seabed. A nozzle for jetting
A support portion configured to be movable in a direction close to the seabed or away from the seabed with respect to the seabed excavator body, comprising a flat plate arranged in parallel with the direction of movement of the seabed excavator body, A support portion provided with a plurality of the nozzles at its lower end,
When a high-pressure water flow for excavating the sea bottom is ejected from the nozzle, a push-down part for pushing down the support part from the predetermined height position toward the sea bottom by a predetermined distance;
A push-down control means for controlling the push-down portion and adjusting the push-down distance of the support portion toward the sea bottom by the push-down portion when a high-pressure water flow for excavating the sea bottom is ejected from the nozzle. When,
A submarine excavator with improved excavation efficiency. In claim 1,
A terrain database for recording terrain data such as undulations on the bottom of the seabed to which pipes or cables are to be embedded, in association with the position coordinate data of the seabed;
Current position estimation means for estimating the current position of the submarine excavator;
Based on the current position data from the current position estimation means and the terrain data from the terrain database, the excavation depth of the seabed by the high-pressure water flow from the nozzle at the current position of the submarine excavator is irrespective of the undulations of the seabed. A depressing distance calculating means for obtaining a distance by which the supporting portion should be depressed by the depressing portion so as to be at a substantially constant depth from the sea surface,
The submarine excavator with improved excavation efficiency, wherein the push-down control means adjusts a push-down distance of the support portion by the push-down portion based on an output from the push-down distance calculating means. 3. The hydraulic motor and the hydraulic tank according to claim 1 or 2, wherein the hydraulic motor and the hydraulic tank are disposed in the vicinity of the support portion, and electric power and a control signal are transmitted from the marine ship to the hydraulic motor via a cable. Submarine excavator with improved drilling efficiency. In any one of Claims 1-3, the two flat plates which comprise the said support part are arrange | positioned so that it may mutually oppose via the distance larger than the diameter of the pipe or cable which should be embed | buried, and at the time of seabed excavation A submarine excavator with improved excavation efficiency, wherein a pipe or cable to be embedded is arranged in a space between the two flat plates.

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