FIELD OF THE INVENTION

The present invention relates to a purpose-built underwater drone for harvesting marine sponges. Furthermore, the present invention relates to the use of the underwater drone for a highly efficient, automated and sustainable method of harvesting marine sponges.

BACKGROUND OF THE INVENTION

Marine sponges produce secondary metabolites that can be used as a natural source for the design of new drugs and cosmetics. In the prior art, generally, such marine sponges are grown in aquacultures. For example, such marine sponges are grown on horizontal ropes, inside small cages or glued to substrate.

One particular example of a method for growing marine sponges is described in DE 101 61 174 C1. In said document, there is described a net structure mounted on a frame. The marine sponges may be grown on the net structure.

Generally, in the prior art, the utilization of underwater drones is known. WO 2017/023953 A1 describes an underwater drone, which is provided with measurement sensors to measure environmental conditions, such as water temperature.

When harvesting marine sponges in the prior art, the complete sponges are harvested using primitive and manual means such as hooks, wires or knives etc. Furthermore, these methods include completely separating the sponges at the basal sponge end from the substrate. However, these methods do not allow for healthy and complete regeneration of the sponges for re-harvesting and can negatively impact the natural habitat of the marine sponge colonies.

The present invention addresses these shortcomings by providing a purpose-built underwater drone for harvesting marine sponges.

SUMMARY OF THE INVENTION

The present invention provides a purpose-built underwater drone that allows efficient, automated and sustainable harvesting of marine sponges. These properties are intrinsic to the configuration of the underwater drone. In particular, the operation mechanism of the inventive underwater drone in combination with the apical and perpendicular cutting of the maritime sponges improves harvesting efficiency. It also prevents their complete distortion and allows them to quickly regenerate in their particular underwater environment ensuring sustainable harvesting. In addition, the highly automated configuration of the inventive underwater drone further eliminates the need for manual harvesting methods as used previously.

Accordingly, to solve the aforementioned problem, the present invention provides:

[1] Underwater drone (6) for harvesting marine sponges (1), comprising a drone body (7) with a propulsion mechanism for underwater movement of the drone (6), the underwater drone (6) is characterized in that a cutting unit (20) is mounted on the drone body (7), which is adapted to cut a marine sponge (1) at an apical sponge end (4), which is distal from a basal sponge end (3).

[2] The underwater drone (6) according to item 1 , characterized in that the cutting unit (20) is constituted by at least one pair of opposite blades (20a, 20b) having cutting edges opposing each other, wherein the opposite blades (20a, 20b) are relatively movable with respect to each other between an open position and a closed position, wherein in the closed position the opposing cutting edges cut the a marine sponge (1) at its apical sponge end (4).

[3] The underwater drone (6) according to item 2, characterized in that the blades (20a, 20b) are adapted to be exchanged, during one session of underwater operation of the underwater drone (6).

[4] The underwater drone (6) according to item 3, characterized in that the drone body (7) comprises a blade cartridge for storing blades (20a, 20b) to be exchanged.

[5] The underwater drone (6) according to any of the foregoing items, characterized in that the drone body (7) further comprises a holding means for holding the cut apical sponge end (4) of the sponge (1), at least after cutting it off.

[6] The underwater drone (6) according to item 5, characterized in that the holding means comprises two opposing pressure elements (23), which are movable with respect to each other between an open position and a closed position, wherein in the closed position, opposing gripping surfaces of the pressure elements (23) clamp a holding region on the outer circumferential surface of the cut apical sponge end (4).

[7] The underwater drone (6) according to item 6, characterized in that the pressure elements (23) are made of an elastic material, which is adapted to conform at least approximately to the outer circumferential surface of the cut apical sponge end (4) at the holding region thereof. [8] The underwater drone (6) according to any of the foregoing items, characterized in that the holding means and/or the cutting unit (20) are mounted about a periphery of a through opening (18) extending in vertical direction of the drone body (7), wherein the through opening (18) is adapted that the marine sponge (1) can extend therethrough, such that the apical sponge end (4) is on a different side of the drone body than the basal sponge end (3).

[9] The underwater drone (6) according to item 8, characterized in that the through opening (18) is cylindrical, in particular rectangular.

[10] The underwater drone (6) according to any of the foregoing items, characterized in that the drone body (7) further comprises at least one buoying means for providing an additionally buoying force to the cut apical sponge end (4), in order to uplift the cut apical sponge end (4) to the water surface.

[11] The underwater drone (6) according to item 10, characterized in that the buoying means is constituted by an inflatable balloon (26), which is adapted to be fixed to the cut apical sponge end (4), and which is adapted to be inflated during the underwater operation of the underwater drone (6) in order to uplift the cut apical sponge end (4) to the water surface.

[12] The underwater drone (6) according to any of the foregoing items, characterized in that the drone body (7) further comprises a pressurized gas storage tank (29), which stores a gas with which the inflatable balloon (26) is inflated.

[13] The underwater drone (6) according to any of the foregoing items, characterized in that the buoying means further comprises a fixing means, which is adapted to fix the buoying means to the cut apical sponge end (4).

[14] The underwater drone (6) according to item 13, characterized in that the fixing means has at least one barb (27) to fix the buoying means to the cut apical sponge end (4).

[15] The underwater drone (6) according to item 13 or 14, characterized in that the drone body (7) further comprises a harpoon mechanism (25), with which the fixing means is shot to the apical sponge end (4) to be fixed thereon.

[16] The underwater drone (6) according to any of items 13 to 15, characterized in that the drone body (7) further comprises a fixing means magazine in which a plurality of fixing means to be loaded into the harpoon mechanism (25) are stored, wherein during underwater operation of the underwater drone (6) a plurality of fixing means are respectively shot to and fixed on subsequently cut apical sponge ends (4). [17] The underwater drone (6) according to any of the foregoing items, characterized in that the drone body (7) further comprises a GPS unit, for identification of the specific operation locations of the drone (6).

[18] The underwater drone (6) according to any of the foregoing items, characterized in that the drone body (7) further comprises at least one camera unit (31 , 33), for acquiring photographic information of the ground situation and/or of the specific sponge to be cut.

[19] The underwater drone (6) according to any of the foregoing items, characterized in that the holding means and/or the cutting unit (20) and/or the harpoon mechanism (25) are pneumatically operated.

[20] Method for harvesting marine sponges (1), wherein the method comprises, cutting a marine sponge (1) at an apical sponge end (4), which is distal from a basal sponge end (3), holding the cut apical sponge end (4) of the sponge (1) at least after cutting it off, shooting a buoying means having a fixing means to subsequently cut apical sponge ends (4) and fixing the buoying means thereon, providing an additionally buoying force to the cut apical sponge end (4) to uplift the cut apical sponge end (4) to the water surface.

Accordingly, the inventive underwater drone has a cutting unit which is mounted on a drone body. The cutting unit is adapted to cut a marine sponge at an apical sponge end. This apical sponge end is an end region of the sponge pertaining to an apex of the sponge. The apical sponge end is a sponge end which is distal from a basal sponge end. The basal sponge end forms the base of the sponge with which is grows on the substrate in the underwater environment.

Marine sponges such as Dysidea avara (Demospongiae, Porifera) usually have a structure wherein from the basal sponge end, one or more tubular arms are growing. One or more of these tubular arms of these sponges are cut by the inventive cutting unit, so as to leave the sponge with its basal sponge end growing on the substrate. One or more apical sponge ends is/are cut off. The cut off sponge ends may be used as a natural source for new drugs and cosmetics. Accordingly, it is an embodiment of the invention to provide a method of harvesting the marine sponges for use as a natural source for new drugs and cosmetics.

From the harvested apical sponge ends, there may be extracted the chitin skeleton and/or Bromtyrosines according to an embodiment of the invention. The inventors found that an underwater drone, which is adapted for underwater movement respectively underwater operation, can carry a cutting unit with which the apical sponge ends may be cut. Thereby the basal sponge end remain on the substrate.

The growing rate at the damage of the sponges due to the cutting of the apical sponge end is much higher, for example in the area of 3 to 5 cm/month, than the growing rate for growing new sponges. Therefore, in accordance with the present invention, a higher efficiency of harvesting marine sponges can be obtained.

According to a further development of the invention, the cutting unit may be constituted by at least one pair of opposite blades. Each of the blades has a respective cutting edge, with which the sponge may be cut at its apical sponge end. The respective opposite cutting edges of the pair of cutting blades cut in between them the respective apical sponge end. This is due to the circumstance that the opposite blades are relatively moveable with respect to each other between an open position and a closed position. In the closed position, the opposing cutting edges cut the marine sponge at its apical sponge end. A closed position is a position in which the distance of the opposing cutting edges is smaller than the distance in the open position. In the closed position, the edges are at least pressed against an outer circumferential surface of the respective sponge end to cut the sponge. By providing at least a pair of opposite blades, the cutting efficiency can be improved.

Due to this blade form geometry, there is provided a smooth and even cutting surface, at which the apical sponge end is cut. If this cutting surface generated at the remaining uncut sponge part is smooth and even, the growing rate of the generated damage is further improved. It is advantageous that the kinematic of the cutting blades is such that the cutting blades cut the apical sponge end in a direction normal to the extension direction of the arm in order to obtain a cutting surface being at least approximately normal to the extension direction of the arm.

The blades may be adapted to be exchanged during one session of underwater operation of the underwater drone. Sometimes it happens that the cutting edge gets blunt or otherwise damaged. In order to prevent the necessity that the underwater drone comes up to the water surface in order to exchange the blades manually, there may be provided at the drone body a blade cartridge in which new blades for cutting the apical sponge ends are stored. If it is detected that a blade is deteriorated, there may be initiated an exchange of the respective damaged blade. The damaged blade may either be stored in a further blade cartridge for used blades or may be simply thrown away into the underwater environment.

Further to the cutting unit, the drone body may further optionally comprise holding means with which the apical sponge end can be held at least after it is cut off with the cutting unit. If the cut apical sponge end is not held after it is cut off, there is the danger that this sponge end floats away and gets lost and, thus, cannot be used as a natural source for drugs and cosmetics. This holding means may hold the respective sponge end not only after it is cut, but also before the cutting takes place. However, at least the sponge end shall be held after cutting takes place. The holding means may be mounted in the vicinity of the cutting blades and/or on top of the cutting blades and may be simultaneously actuated during the actuation of the cutting blades.

According to a further development of the invention, the holding means comprises two opposing pressure elements, which are moveable with respect to each other between an open position and a closed position. Said pressure elements may be mounted on top of a respective cutting blade, e.g. in a one to one relation. Such a pressure element may be fixed to the respective cutting blade and may protrude the cutting edge of the cutting blade in a cutting direction thereof. In the closed position, opposing gripping surfaces of the pressure elements clamp a holding region on the outer circumferential surface of the cut apical sponge end. The holding region is a region in which the pressure element holds the apical sponge end. The kinematic of the opposed pressure elements may be similar to the kinematic of the opposed blades of the cutting unit. In an open position, the distance between the opposing gripping surfaces may be higher than the distance of the opposing gripping surfaces in the closed position. In the closed position, the respective opposing gripping surfaces clamp the cut apical sponge end to hold it. While the respective opposing pressure elements are moveable with respect to each other in a horizontal plane, this may be implemented in that one of the pressure elements is fixed and the other is moveable, or in that both of the opposing pressure elements are moveable. Preferably, the plane of movement of the opposing pressure elements is at least parallel to the plane of movement of the opposing blades of the cutting unit.

It may be the case that the respective pressure elements are mounted adjacent to respective blades of the cutting unit, for example, a pressure element may be mounted, when viewed in the vertical direction of the drone body from top to bottom, above or below the respective blade of the cutting unit. The opposing pressure elements and the opposing blades may be simultaneously actuated. However, the opposing pressure element shall hold the cut apical sponge end at least after it is cut.

It is advantageous that the pressure elements are made of an elastic material which is adapted to conform at least approximately to the outer circumferential surface of the cut apical sponge end at the holding region thereof. If there is provided such an elastic material, the fixation of the sponge end, which is cut off, is improved while the respective arm/outer circumferential surface of the cut sponge is not significantly damaged or squeezed. It is beneficial that the holding means and/or the cutting means are mounted about the periphery of a through opening, which through opening extends in the vertical direction of the drone body. The through opening may be an opening which is adapted such that the marine sponge can extend through the opening such that the apical sponge end is on a different side of the drone body than the basal sponge end. The area of the through opening may be in the region up to 2,080 cm ² , up to 2,000 cm ² , up to 1 ,500 cm ² , up to 1 ,000 cm ² , up to 750 cm ² , up to 500 cm ² , up to 400 cm ² . These values as such may constitute an upper limit of the area of the through opening. In various embodiments of the invention, the area of the through opening may be in any one of the regions between 400 cm ² to 2,080 cm ² , between 400 cm ² to 2,000 cm ² , between 400 cm ² to 1 ,500 cm ² , between 400 cm ² to 1 ,000 cm ² , between 400 cm ² to 750 cm ² , and between 400 cm ² to 500 cm ² . These values as such may constitute an upper or lower limit of the area of the through opening.

The drone body may have a planar horizontal structure, e.g. a ray-like structure. The through opening may be provided in a planar area of the drone body. This opening may be provided in approximately a central position of the drone body for balancing reasons.

Therefore, when the underwater drone approaches a marine sponge to be harvested, the underwater drone is moved to a location above the sponge and/or sponge arm to be cut. Then the underwater drone, after it is in a predetermined position above the sponge and/or sponge arm to be cut, may be moved, e.g. by remote control, downward such that the arm of the sponge extends through the through opening. After there is detected that the underwater drone is in the correct cutting position, the cutting unit and optionally the holding means may be actuated to cut off and possibly hold the cut sponge end.

The through opening may be cylindrical, in particular it may have a rectangular form. Other preferred geometries are a D-form, an O-form, a circular form, an oval form. However, it is advantageous that the through opening is placed centrally in the drone body.

According to a further advantageous embodiment, the underwater drone may further comprise a buoying means which may provide an additional buoying force to the cut apical sponge end such that the cut apical sponge end can be uplifted to the water surface and float on the water surface. The buoying means may also have the functionality that the cut apical sponge end is better detectable on the water surface after it is uplifted. The buoying means may have a good visible color such as yellow or red or may have any other feature that makes it better detected when it is floating on the water surface, such as a radar or other electromagnetic detecting element.

It is advantageous that the buoying means is constituted by an inflatable balloon. This balloon can be fixed to the cut apical sponge end. This balloon can be inflated during the underwater operation of the underwater drone. Thereby there is generated an additional buoying force to the cut apical sponge end in order to uplift the cut apical sponge end to the water surface. The inflatable balloon may be inflated by a pressurized gas which comes from a pressurized gas storage tank which may be mounted on and/or in the drone body. As pressurized gas, there may be used air, oxygen, nitrogen, helium, or mixtures thereof, or any other known gasses which may cause additional buoying force when the inflatable balloon is fixed to the cut apical sponge end. By applying such a buoying means to the cut sponge end, it is easy to transfer the cut sponge ends to the water surface and to harvest or collect the cut sponge ends just from the water surface.

The buoying means may comprise a fixing means, which is adapted to fix the buoying means to the cut apical sponge end. As such fixing means, there may be provided at least one barb or a plurality of barbs which may interact with the cut sponge end to fix the buoying means on the cut sponge end.

The fixing means may be fixed to the sponge end by a harpoon mechanism with which it is shot to the sponge end to be fixed thereon. The harpoon mechanism may be loaded with such a fixing means such that such buoying means comprising the fixing means and thus the respective buoying means are shot to the cut sponge end with the harpoon mechanism. This harpoon mechanism may be automatically loaded with the buoying means after one buoying means has been shot to the cut sponge end.

This loading may be done automatically, or manually via remote control of an operator. There may be provided a sensor assigned to the harpoon mechanism, which detects whether the harpoon means is loaded with a buoying means comprising the fixing means or not. In the case the harpoon means is not loaded, it may be automatically instructed that the buoying means is loaded to the harpoon mechanism. In accordance with a further preferred embodiment of the present invention, the drone body may further comprise a fixing means magazine in which a plurality of fixing means to be loaded into the harpoon mechanism, are stored. During one single session of underwater operation of the underwater drone, a plurality of fixing means may be respectively shot to and fixed on to the cut apical sponge ends. Thus, in order to load the fixing means to the harpoon mechanism, it is not necessary that the drone comes up to the water surface.

According to a further preferred embodiment of the invention, the underwater drone body further may comprise a GPS unit for the identification of the specific operation locations of the drone. This GPS unit may communicate with a control station with which the drone is operated by a user and sends the GPS position of the drone to the control station. With the help of an underwater map, the respective location where the sponges are harvested, or are to be harvested may be determined.

According to a further preferred embodiment of the invention, the underwater drone may further comprise at least one camera unit.

With this camera unit, a photograph of the ground situation and/or the specific sponge to be cut may be obtained. This camera unit may take a video sequence or single photograph/frame during the underwater operation of the drone. With the help of this camera unit, the drone may be placed in a specific position above the sponge to be cut and then lowered in its position such that the sponge end extends through the through opening before it is cut.

With this camera unit, there may also be acquired surrounding environment information where the cut sponge ends are grown.

By combination with the GPS information and the information from the camera unit, when, for example, after several days, weeks, or months the specific location where a sponge has been cut is visited, there may be evaluated whether the sponge has regenerated and how much the sponge end has grown, at the damaged/cut location, since it was damaged/cut.

The respective cutting unit, holding means, buoying means, fixing means, harpoon mechanism, GPS unit, camera unit (as long as such a unit/ means is provided) may each together or independently be controlled by a CPU mounted on or in the drone body.

In the CPU, there may be stored a software/application which serves as an operating system for the drone.

The drone may be a remote controlled drone, wherein the control station of the user may be provided with a screen and/or a data analysis unit in which the data acquired by the drone may be analyzed.

If, for example, a point, location and/or area where the sponges may be harvested, is given as input, the drone can, for example, operate fully autonomously. For example, with the camera unit, the specific sponges to be harvested can be selected, the drone can place itself in the specific location and the specific orientation to harvest the apical sponge end.

The holding mechanism and/or the cutting mechanism and/or the harpoon mechanism may be operated fully automatically. Alternatively these mechanisms may also be manually operated by the used via a remote control.

The control may be done by application stored in the CPU provided on the drone body. Although there is described at least one camera unit, there may be provided a plurality of camera units around the through opening and/or there may be provided a further camera on the front side of the drone. It the region of the camera, there may be provided lighting devices such as LED to light the surrounding of the images to be acquired.

According to a further aspect of the invention, there is provided a method for harvesting marine sponges.

The method has the features defined in claim 20/item 20.

The method may be executed with the underwater drone defined in claims I items 1 to 19.

In particular, the method comprises the cutting of a marine sponge at an apical sponge end thereof. In a preferred embodiment, method further comprises cutting the sponge perpendicular to its longitudinal extension/ longitudinal axis. At least after cutting, the cut apical sponge end is held. During the holding of the cut apical sponge end, a buoying means comprising a fixing means is shot to subsequently cut apical sponge ends. Thereby a respective buoying means is fixed to a cut sponge end. Via the buoying force provided from the buoying means, the cut apical sponge end is uplifted to the water surface to be harvested.

BRIEF DESCRIPTION OF FIGURES

Further advantages of the invention will become apparent on the specific embodiment which are described with respect to the subsequent figures.

Therein it is shown in

Figure 1 an example of harvesting sponges by cutting apical sponge ends thereof,

Figure 2 an example of underwater drone viewed from an angle from above,

Figure 3 an alternative view of the underwater drone of Figure 2, when viewed in a vertical direction along a line from top to bottom of the drone body,

Figures 4 a, b, c, d, different equipment mounted on the underwater drone of figures 2 and 3,

Figure 5 a, b, c, d, e, f, different steps of harvesting the marine sponge, and

Figure 6 a and b, a location of the ground surface underwater environment after cutting the apical sponge ends (Figure 6a) and the same location 2 months after the cutting and harvesting of the apical sponge ends (Figure 6b). DETAILED DESCRIPTION OF THE INVENTION

In Figure 1 , there is depicted a sketch how the harvesting of the maritime sponges work. On the left hand side of figure 1 , there is depicted a sponge 1 having two arms 2a, 2b. The sponge has a basal sponge end 3 and an apical sponge end 4, where the basal sponge end 3 constitutes the base of the sponge 1 . Via the basal sponge end 3, the sponge grows on the substrate which, for example, the maritime ground.

The arms 2a, 2b have a tubular form and extend in a longitudinal direction.

With the inventive method which is executed with the inventive underwater drone described below, the sponge 1 is cut as shown in the middle section of figure 1 at the apical sponge end site, so as to leave the sponge with its basal sponge end 3 growing on the substrate. Namely, one or more apical sponge ends is/are cut off. The cut off sponge ends may be used as a natural source for new drugs and cosmetics. Accordingly, in a preferred embodiment, the sponge is cut at its apical end. In a further embodiment, the cut off sponge is used as a natural source for new drugs and cosmetics.

In the particular case, the two arms 2a, 2b are cut off simultaneously while they extend through the through opening of the drone body described below. However, one or more arms may be cut simultaneously. Accordingly, in an embodiment of the invention, two arms of the sponge are cut off simultaneously. In another embodiment, one or more arms may be cut simultaneously.

The cutting is executed such that the cutting surface 5a separating the basal sponge end 3 from the apical sponge end 4 extends perpendicular or approximately perpendicular to the longitudinal extension of the respective arm 2a, 2b. At the cutting surface 5a, located at the basal sponge end, as shown in figure 1 on the right hand side, the arms may heal and grow new. Accordingly, in a preferred embodiment, the sponge is cut perpendicular to its longitudinal extension/axis.

In the present invention, the term “perpendicular cutting” (or similar terms used herein) includes “approximately perpendicular cutting” or “about perpendicular cutting”. In various embodiments, the term “approximately perpendicular cutting” or “about perpendicular cutting” may mean cutting at an angle of at least 75°, or at least 80° to the respective longitudinal extension or axis. In various embodiments, the term “approximately perpendicular cutting” or “about perpendicular cutting” may mean cutting at an angle of at least 85°, 86°, 87°, 88°, or 89°, relative to the respective longitudinal extension or axis. Most preferably, the term “perpendicular cutting” (or similar terms used herein) means cutting at an angle of at approximately or about 90°, or even specifically 90°, relative to the respective longitudinal extension or axis. It was noticed that with the basal sponge end, and thus a living part of the sponge is left growing on the substrate, the regeneration of the sponge is much faster than the growth of a new sponge. Therefore, it is beneficial to only cut the sponge so that it stays growing on the substrate where only a part of the sponge, in particular the apical sponge end is harvested.

The cutting surface 5a being approximately perpendicular to the extension direction of the sponge end is beneficial to improve the regeneration rate after damaging/cutting the sponges. As depicted on the upper portion of figure 1 , from the cut and harvested apical sponge ends 4, there may be extracted in the particular example the chitin skeleton and/or Bromtyrosines. The present invention is in the following explained for harvesting Dysidea avara (Demospongiae, Porifera), however, can be applied to any maritime sponges. In particular, sponges can be preferably harvested which have a growing constitution having arms extending from a basal sponge end. However, any other geometry such as compact geometry without arms can also be harvested with the inventive method executed by the inventive underwater drone. Accordingly, it is an embodiment of the invention to provide a method of harvesting maritime sponges. In a preferred embodiment, the maritime sponge is Dysidea avara (Demospongiae Porifera).

There may be cut simultaneously one single arm or a plurality of arms of one or more sponges. This basically depends on the configuration of the cutting unit, and further this may depend on the opening area of the through opening of the underwater drone which is described later.

In figure 2, there is depicted a specific example of an underwater drone 6, a top view in a vertical direction from top to bottom of the drone shown in figure 2, is shown in figure 3.

The drone 6 has a drone body 7 serving as a floating body in and/or on which different functionalities may be implemented.

In the specific case the drone body 7 has a planar shape, with two surfaces, an upper body surface 8 and a lower body surface 9. The upper body surface 8 and the lower body surface 9 are distanced from each other via the edge 10 of the drone body 7.

The drone body 7 has a shape similar to a ray (ray-like conformation), wherein at the frontal portion 11 , there is provided an arrow like configuration, and on a rear portion 11 the edge extends perpendicular to the longitudinal direction of the drone body 7.

In the following, the longitudinal direction of the drone body is determined as the direction along the longest extension of the drone. The longitudinal direction corresponds to the x axis in figure 2 and 3. The bottom to top direction corresponds to the vertical direction and corresponds to the y axis in figure 2 and 3. The horizontal direction is the direction corresponding to the extension of the upper body surface 8 and the lower body surface 9. The transversal direction is the direction along the z axis in figures 2 and 3.

Although in the embodiments, there is shown the ray like constitution of the drone body, the drone body may have any constitution, e.g. a torpedo like conformation, as long as it is possible to use it as underwater drone.

As propulsion mechanism, in the specific embodiment, there are mounted two first propellers 14 each mounted to a shaft 13, which shaft extends in the longitudinal direction of the drone body 7. This shaft 13 may be actuated by a motor, which is not shown in the specific figures.

Further to the first propellers 14, which are adapted predominantly for forward and rearward movement of the underwater drone 1 , in the specific embodiment there are provided four second propellers 15, which are aligned in the vertical direction along the upper body respective the lower body surface 8, 9. Via said second propellers 15, the adjustment in the high overground may be executed. This second propellers 15 may likewise be actuated by a further motor, for example, a second motor or may be actuated by the first motor via which the first propellers 14 are actuated.

Also, it may be the case that each of the propellers 14, 15 is equipped with a separate motor with which each propeller may be operated independently from each other.

The two first propellers 14 are summarized in the following as forward and/or rearward propelling means while the second propellers 15 are identified as up and/or down propelling means.

In the specific embodiment, there are shown four propellers 15 being used as up and/or down propelling means at the respective four corners of the drone body 7. However, it is not necessarily the case to provide four second propellers 15, there may also be provided one, two, or a plurality of second propellers 15. The up and/or down propelling means is also not delimited to the utilization of propellers, there may also be provided one or more jet generation means or any other means generating a propelling force.

Also in the specific case, there are provided two first propellers 14, each at a respective longitudinal edge of the body, at the rear portion 12 of the drone body 7, there may only be provided one first propeller 14 or more than two first propellers. The forward and/or rearward propelling means is also not delimited to the utilization of propellers, there may also be provided one or more jet generation means or any other means generating a propelling force. However, the forward and/or rearward propelling means and the up and/or down propelling means might be combined as one propelling unit.

The drone 1 body further comprises two floating bodies 16a, 16b, each one is integrated in the drone body 7 at the opposite longitudinal edges thereof. Each floating body 16a, 16b is provided with fins 17 for stabilizing the drone 1. In the specific case, there are provided three fins 17 on each of the floating bodies 16a, 16b. However, any number of fins may be provided or the fins may also be omitted completely.

Between the floating bodies 16a, 16b, in a central section of the drone body 7 there is provided a through opening 18, which extends in a vertical direction.

As shown in figure 3, in the view along the vertical axis from top to bottom, the though opening 18 has in the particular case, a rectangular geometry, with shorter edges extending along the longitudinal direction along the floating bodies 7 and longer edges extending in transverse direction of the floating bodies 7.

This through opening 18 has such dimensions after that the drone may be guided to a location where a specific sponge should be harvested, the drone 1 is placed above this sponge such that the apical sponge end, specifically the arm or arms of the sponge does not yet extend through the through opening 18. Thereafter, the drone is lowered with the help of the up and/or down propelling means, namely the second propellers 15 to be placed such that the arm or arms of the sponge extends through the through opening 18 before it is cut. An example of this configuration is, for example, shown in figure 5a. The cutting unit 20, which is described later, may be placed at any location at or in the drone body 7, which allows the cutting of an apical sponge end such that the basal sponge end remains fixed on the substrate.

As shown in figures 2 and 3, at the lateral edges of the drone body 7, that means the edges which are directed in the longitudinal direction of the drone body 7, there is provided a respective cutting blade 20a, 20b. Each cutting blade 20a, 20b has a cutting edge with which the apical sponge end 4 of a sponge may be cut.

In order to do so, the blades 20a, 20b are moved with respect to each other into a location in the direction of a central part of the through opening 18 such that, as shown in figure 5b, the apical sponge end 4 is cut with the cutting edges of the opposing cutting blades 20a, 20b. The two cutting blades 20a, 20b form the cutting unit 20. Although in the present example, the cutting blades 20a, 20b are positioned at lateral edges 19 of the through opening 18, as long as a through opening 18 is provided, the cutting edges may also be provided along the edges extending in transverse direction. There may also be provided two cutting blades as shown in figures 2 and 3, which are provided at the lateral edges 19 of the through opening 18, and two further cutting blades at the respective edges of the through opening 18 extending in the transverse direction, such that in total the apical sponge end 4 is cut by four blades.

The extension direction of the cutting blade and thus the cutting edge is in the present example slightly tilted with respect to the longitudinal direction of the drone body. This is not necessarily the case, but has a beneficial effect on the cutting of the apical sponge ends 4. It is not shown in these figures that this cutting blades 20a, 20b may be exchanged during underwater operation. In order to do so, the underwater drone 6 may be provided with a blade cartridge for storing the blades 20a, 20b to be exchanged. The blades 20a, 20b may be exchanged via remote control by a user or automatically, if a sensor senses that a blade is destroyed or damaged.

In order to do so, and also in order to provide further functionalities of the drone, the drone 6 may be provided with a computer means 21 (see figure 4a,b,c,d). The computer means 21 may comprise a CPU and an application stored in the computer means 21. Within the computer means 21 , there may be incorporated a GPS module which is not shown. Such a GPS module may be also provided as separate element, separate from the CPU.

Via the computer means 21 , there may be established a communication to a remote control station, which is placed above the water surface with which the drone 6 may be operated by an operator. The remote control station may comprise a screen on which the respective data and/or pictures and/or videos taken by the drone 6 are visible for the operator. The drone may be completely autonomous, wherein it moves along predetermined way points to harvest the sponges, with the help of a later described camera function in combination with the GPS. The sponges may be autonomously searched and harvested along the predetermined way points.

Alternatively, the operation of the drone 6 can executed be manually by an operator by the remote control station. The computer means 21 is connected to the different functionalities such as the cutting unit 20, the propulsion mechanism, and the further means outlined in the following.

Connected to the computer means 21 , there may also be sensors sensing different physical properties such as the damaging of the cutting blades.

In the particular example, the cutting unit 20 is pneumatically actuated, therefore, as schematically shown in figure 4b, there are provided some pneumatic connectors 22 for e.g. connecting a pneumatic actuator to the cutting unit and the like.

Further to the cutting unit 20, the drone 6 is provided with a holding means. In the present case, the holding means is constituted by the two opposing pressure elements 23 (see figure 2 and 3) which are aligned with the cutting blades 20a, 20b. In the particular case, there is one pressure element assigned to each of the blades 20a, 20b.

As shown in figure 5b, c, d, e, and f during and after cutting off the apical sponge end 4, the apical sponge end 4 is prevented from being lost by being held between the pressure elements 23. Each pressure element has at least one pressure surface 24a, 24b. Between the adjacent pressure surfaces 24a, 24b, the respective outer circumferential surface of the apical sponge end 4 is held.

In the present case, the pressure elements 23 are extending in the same direction as the blades 20a, 20b, namely slightly offset tilted from the longitudinal direction of the drone body 7. This pressure element 23 may be made from an elastic material such that the outer contour of the pressure surface 24a, 24b can be adapted during gripping to the outer circumferential surface of the apical sponge end 4 which was cut. The pressure elements 23, in the present case are likewise pneumatically actuated via the pneumatic connectors 22 and a pneumatic actuator, which not shown in the figures for the present embodiment.

In order to provide a buoying force to the harvested apical sponge end 4, there is provided in the inventive underwater drone 6 a harpoon mechanism 25, which is not shown in figures 2 and 3, but which is shown schematically in figure 5b, c, d, e, and f.

Via this harpoon mechanism 25, an inflatable balloon 26, which has at the side facing the cut sponge end, a plurality of barbs 27 serving as fixing means, is shot to the cut sponge end to fix the inflatable balloon 26 thereto. Via the harpoon mechanism 25 which has a pushing rod 28 (see fig. 5e, f), which pushes against the rear side of the inflatable balloon 26, the inflatable balloon 26 including the plurality of barbs 27 is shot to the cut sponge end, which is held by the pressure element 23 (see figure 5b, c, d).

As shown in figure 5d, the inflatable balloon 26 is thus fixed on an outer circumferential surface of the cut sponge end. The described balloon 26 is an example of the buoying means. It is preferential to provide any buoying means and fix it to the cut sponge end in order to have an additional buoying force such that the cut sponge end can be uplifted and float then on the water surface and then harvested from the water surface.

The inflatable balloon 26 as shown in figure 5e, after it is fixed to the cut sponge end, is inflated via air. However, any gas such as oxygen, nitrogen, helium, or a mixture there of may be used.

This gas is stored, for example, in the storage tanks 29 shown in figure 4c which may be provided at the lateral edges of the through opening 18 and extending in longitudinal direction of the drone body 7. In the particular case, the storage tanks 29 contain pressurized air with which the balloon is inflated. This inflation may be done by an inflation tube which is mounted on the harpooning mechanism 25 and which is connected to the inflatable balloon 26.

As shown in figure 5e, after the inflatable balloon 26 is inflated, there is generated an additional buoying force which may uplift to the cut sponge end. After inflating the balloon 26, the inflation tube may be decoupled from the balloon 26. After the holding means with the pressure elements 23 (see figure 5f) is detached from the cut sponge end and retracted into an open position, the cut sponge end may be uplifted with the buoying force of the inflated balloon 26 to be harvested.

The inflatable balloons having the barbs 27 may be stored in a magazine which is named in the claims and general description fixing means magazine. The plurality of stored inflatable balloons 26 including the barbs 27, are shown in figure 4a, b, c, d and 5a, b, c, d, e, and f.

This fixing means magazine is provided adjacent to the harpooning mechanism 25. The harpooning mechanism 25 may be loaded with the inflatable balloons 26 including the barbs 27 before a respective inflatable balloon 26 is shot at the cut sponge end to be fixed thereon. As described in the foregoing section and shown in figures 5a,b,c,d,e,f, one or a plurality of sponges and/or sponge arms and/or one or a plurality of apical sponge ends may be cut simultaneously with the underwater drone 6 which may be moved from sponge to be harvested to sponge to be harvested.

The control is done by the aforementioned computer means 21 , via the remote control station by an operator, or completely autonomously along a predetermined way points.

The underwater drone 6 is further provided with different camera means. A first camera means 31 (see fig. 1 and 5a) comprises an upper high resolution camera and a lower high resolution camera, which are provided at the frontal portion 11 of the drone body 7. Adjacent to the first camera means 31 , there is a lighting means 32 provided, which in the present case is constituted by a plurality of high intensity LEDs mounted at the forward edge of the floating body.

With the first camera means 31 , navigation underwater may be facilitated. This camera means may be connected to the computer means 21 . In the computer means 31 , there may be stored an application, which concerns the processing of the acquired data from the first camera means 31 and sending it to the remote control station. Thereby, it can be navigated through the underwater environment.

Additionally, to the first camera means 31 , for acquiring the information for forward navigation, there may be provided a second camera means 33 (see figure 4b, d), which is in the present case, constituted by three high precision cameras 33, which are mounted around the through opening 18. With this second camera means 33, the specific location of the sponge to be harvested may be photographed or a video may be taken from the specific location. The visual data is saved in the computer means 21 or transferred to the remote control station, e.g. together with the GPS data. Thus is can be assigned the figure to the specific location where the sponge was harvested from. With such a constitution, it is possible, as shown in figure 6 a, b, to come back later with the drone, for example in one day, three days, one week, or some months, to control the respective growth of the damaged sponges.

Figure 6a, shows a photo acquired directly after the sponges are cut. Figure 6b shows a photo acquired after two month at the same location corresponding to the location in figure 6a.

The place with the oval contour in said figures are the same locations. It can be derived therefrom that the damaged arm of the sponge is regrown. Therefore, there can also be obtained a monitoring of growing of the sponges after harvesting.

The aforementioned functionalities of the specific underwater drone are only described as examples but are not meant for delimiting the present invention. The present invention is covered by the claims, and all elements defined in the specific description may be optionally and independently provided as it is desired.

Further to the underwater drone itself, the present invention is also related to a method for harvesting sponge as described elsewhere herein.

Therefore, as long as there are described apparatus related features, this may be as long as the method is concerned, also reformulated as method related features.

Reference sign list

1 Sponge

2, 2a, 2b Arm

3 Basal sponge end

4 Apical sponge end

5a Cutting surface

6 Drone

7 Drone body

8 Upper body surface

9 Lower body surface 10 Edge

11 Frontal portion

12 Rear portion

13 Shaft

14 First Propeller

15 Second propeller

16a, 16b Floating body

17 Fin

18 Through opening

19 Lateral edges (edges in longitudinal direction of the body)

20 Cutting unit

20a, 20b Cutting blade

21 Computer means

22 Pneumatic connector

23 Pressure element

24a, 24b Pressure surface

25 Harpoon mechanism

26 Inflatable balloon

27 Barb

28 Pushing rod

29 Pressurized gas container

31 First camera means

32 Lightning means

33 Second camera means

Aspects and embodiments of the Invention / Claims encompass the following:

1. Underwater drone (6) for harvesting marine sponges (1), comprising a drone body (7) with a propulsion mechanism for underwater movement of the drone (6), the underwater drone (6) is characterized in that a cutting unit (20) is mounted on the drone body (7), which is adapted to cut a marine sponge (1) at an apical sponge end (4), which is distal from a basal sponge end (3).

2. The underwater drone (6) according to claim 1 , characterized in that the cutting unit (20) is constituted by at least one pair of opposite blades (20a, 20b) having cutting edges opposing each other, wherein the opposite blades (20a, 20b) are relatively movable with respect to each other between an open position and a closed position, wherein in the closed position the opposing cutting edges cut the a marine sponge (1) at its apical sponge end (4).

3. The underwater drone (6) according to claim 2, characterized in that the blades (20a, 20b) are adapted to be exchanged, during one session of underwater operation of the underwater drone (6).

4. The underwater drone (6) according to claim 3, characterized in that the drone body (7) comprises a blade cartridge for storing blades (20a, 20b) to be exchanged.

5. The underwater drone (6) according to any of the foregoing claims, characterized in that the drone body (7) further comprises a holding means for holding the cut apical sponge end (4) of the sponge (1), at least after cutting it off.

6. The underwater drone (6) according to claim 5, characterized in that the holding means comprises two opposing pressure elements (23), which are movable with respect to each other between an open position and a closed position, wherein in the closed position, opposing gripping surfaces of the pressure elements (23) clamp a holding region on the outer circumferential surface of the cut apical sponge end (4).

7. The underwater drone (6) according to claim 6, characterized in that the pressure elements (23) are made of an elastic material, which is adapted to conform at least approximately to the outer circumferential surface of the cut apical sponge end (4) at the holding region thereof.

8. The underwater drone (6) according to any of the foregoing claims, characterized in that the holding means and/or the cutting unit (20) are mounted about a periphery of a through opening (18) extending in vertical direction of the drone body (7), wherein the through opening (18) is adapted that the marine sponge (1) can extend therethrough, such that the apical sponge end (4) is on a different side of the drone body than the basal sponge end (3). The underwater drone (6) according to claim 8, characterized in that the through opening (18) is cylindrical, in particular rectangular. The underwater drone (6) according to any of the foregoing claims, characterized in that the drone body (7) further comprises at least one buoying means for providing an additionally buoying force to the cut apical sponge end (4), in order to uplift the cut apical sponge end (4) to the water surface. The underwater drone (6) according to claim 10, characterized in that the buoying means is constituted by an inflatable balloon (26), which is adapted to be fixed to the cut apical sponge end (4), and which is adapted to be inflated during the underwater operation of the underwater drone (6) in order to uplift the cut apical sponge end (4) to the water surface. The underwater drone (6) according to any of the foregoing claims, characterized in that the drone body (7) further comprises a pressurized gas storage tank (29), which stores a gas with which the inflatable balloon (26) is inflated. The underwater drone (6) according to any of the foregoing claims, characterized in that the buoying means further comprises a fixing means, which is adapted to fix the buoying means to the cut apical sponge end (4). The underwater drone (6) according to claim 13, characterized in that the fixing means has at least one barb (27) to fix the buoying means to the cut apical sponge end (4). The underwater drone (6) according to claim 13 or 14, characterized in that the drone body (7) further comprises a harpoon mechanism (25), with which the fixing means is shot to the apical sponge end (4) to be fixed thereon. The underwater drone (6) according to any of claims 13 to 15, characterized in that the drone body (7) further comprises a fixing means magazine in which a plurality of fixing means to be loaded into the harpoon mechanism (25) are stored, wherein during underwater operation of the underwater drone (6) a plurality of fixing means are respectively shot to and fixed on subsequently cut apical sponge ends (4). The underwater drone (6) according to any of the foregoing claims, characterized in that the drone body (7) further comprises a GPS unit, for identification of the specific operation locations of the drone (6). 18. The underwater drone (6) according to any of the foregoing claims, characterized in that the drone body (7) further comprises at least one camera unit (31, 33), for acquiring photographic information of the ground situation and/or of the specific sponge to be cut. 19. The underwater drone (6) according to any of the foregoing claims, characterized in that the holding means and/or the cutting unit (20) and/or the harpoon mechanism (25) are pneumatically operated.

20. Method for harvesting marine sponges (1), wherein the method comprises, cutting a marine sponge (1) at an apical sponge end (4), which is distal from a basal sponge end (3), holding the cut apical sponge end (4) of the sponge (1) at least after cutting it off, shooting a buoying means having a fixing means to subsequently cut apical sponge ends (4) and fixing the buoying means thereon, providing an additionally buoying force to the cut apical sponge end (4) to uplift the cut apical sponge end (4) to the water surface.