AUTOMATED ANCHOR MANAGEMENT

Abstract

A technique of managing an anchor in a surface vessel includes receiving, by a computerized apparatus aboard the surface vessel, a geographical bounding box within which an anchor of the surface vessel is to be dropped, and applying, by the computerized apparatus, a plurality of filters to the geographical bounding box, the plurality of filters excluding regions within the geographical bounding box at which conditions are unsuitable for anchoring. After the surface vessel has navigated to a region within the geographical bounding box that is not excluded by the plurality of filters, the technique further includes electronically initiating a drop-anchor procedure to drop the anchor automatically within said region.

Claims

1. A method of managing anchoring in a surface vessel, comprising: receiving, by a computerized apparatus aboard the surface vessel, a geographical bounding box within which an anchor of the surface vessel is to be dropped; applying, by the computerized apparatus, a plurality of filters to the geographical bounding box, the plurality of filters excluding regions within the geographical bounding box at which conditions are unsuitable for anchoring; and after the surface vessel has navigated to a region within the geographical bounding box that is not excluded by the plurality of filters, electronically initiating a drop-anchor procedure to drop the anchor automatically within said region.

2. The method of claim 1, wherein the drop-anchor procedure includes: measuring, via an electronic encoder operatively coupled to the computerized apparatus, an amount of anchor line dispensed from the USV when dropping the anchor; and upon the measured amount of anchor line reaching a preset length, activating, by the computerized apparatus, an anchor stop that prevents the anchor line from being further dispensed.

3. The method of claim 2, wherein applying the plurality of filters includes: rendering the geographical bounding box as multiple rectangles of uniform dimensions; and removing rectangles as candidates for anchoring based on unsuitable anchoring conditions within geographical regions represented by such rectangles.

4. The method of claim 3, wherein the unsuitable anchoring conditions include a geographical region represented by a rectangle falling within a shipping lane where other vessels are known to travel.

5. The method of claim 3, wherein the unsuitable anchoring conditions include a predetermined swing circle around a geographical region represented by a rectangle intersecting land.

6. The method of claim 3, wherein the unsuitable anchoring conditions include a predetermined swing circle around a geographical region represented by a rectangle intersecting shallow water.

7. The method of claim 3, wherein applying the plurality of filters is performed one filter at a time, with each filter excluding all rectangles that indicate unsuitable anchoring conditions with respect to that filter.

8. The method of claim 3, further comprising, after performing the drop-anchor procedure, monitoring conditions around the surface vessel and raising the anchor upon detecting of an adverse condition.

9. The method of claim 8, further comprising the computerized apparatus releasing the anchor stop prior to raising the anchor.

10. The method of claim 8, wherein detecting the adverse condition includes detecting that the anchor is being dragged.

11. The method of claim 8, wherein detecting the adverse anchoring condition includes detecting that another vessel has entered a swing circle of the USV.

12. The method of claim 3, further comprising: monitoring, by the computerized apparatus, a tension of the anchor line; in response to detecting a stuck-anchor condition based at least in part on the anchor line tension, directing, by the computerized apparatus, a saw to cut through and release the anchor line.

13. The method of claim 3, wherein monitoring the anchor line tension includes measuring a direction of tension based on a plurality of load cells coupled to an anchor port through which the anchor line passes.

14. A surface vessel, comprising: a vessel hull; an anchor coupled to an anchor line; and a computerized apparatus aboard the surface vessel, the computerized apparatus constructed and arranged to: receive a geographical bounding box within which an anchor of the surface vessel is to be dropped; apply a plurality of filters to the geographical bounding box, the plurality of filters excluding regions within the geographical bounding box at which conditions are unsuitable for anchoring; and after the surface vessel has navigated to a region within the geographical bounding box that is not excluded by the plurality of filters, electronically initiate a drop-anchor procedure to drop the anchor automatically within said region.

15. The surface vessel of claim 14, further comprising: an electronic encoder operatively coupled to the computerized apparatus, the electronic encoder constructed and arranged to measure an amount of anchor line dispensed from the surface vessel when dropping the anchor; and an anchor stop operatively coupled to the computerized apparatus, the anchor stop constructed and arranged to prevent the anchor line from being further dispensed once the measured amount of anchor line reaches a preset length.

16. The surface vessel of claim 14, further comprising: an anchor port formed in the vessel hull and providing a passageway through which the anchor line passes; and a saw operatively coupled to the computerized apparatus and physically coupled to the anchor port, the saw constructed and arranged to cut through the anchor line in response to a command from the computerized apparatus.

17. The surface vessel of claim 16, further comprising a plurality of load cells coupled to the anchor port and to the computerized apparatus, the plurality of load cells enabling the computerized apparatus to determine an angle of tension of the anchor line.

18. A computer program product including a set of non-transitory, computer-readable media having instructions which, when executed by control circuitry of a computerized apparatus, cause the computerized apparatus to perform a method of managing anchoring of a surface vessel, the method comprising: receiving a geographical bounding box within which an anchor is to be dropped; applying a plurality of filters to the geographical bounding box, the plurality of filters excluding regions within the geographical bounding box at which conditions are unsuitable for anchoring; and after the surface vessel has navigated to a region within the geographical bounding box that is not excluded by the plurality of filters, electronically initiating a drop-anchor procedure to drop the anchor automatically within said region.

19. The computer program product of claim 18, wherein applying the plurality of filters includes: rendering the geographical bounding box as multiple rectangles of uniform dimensions; and removing rectangles as candidates for anchoring based on unsuitable anchoring conditions within geographical regions represented by such rectangles.

20. The computer program product of claim 19, wherein applying the plurality of filters is performed one filter at a time, with an application of each filter excluding all rectangles that indicate unsuitable anchoring conditions with respect to that filter.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0009] The foregoing and other features and advantages will be apparent from the following description of particular embodiments, as illustrated in the accompanying drawings, in which like reference characters refer to the same or similar parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments.

[0010] FIG. 1 is a block diagram of an example USV (Uncrewed Surface Vessel) with which embodiments of the improved technique can be practiced.

[0011] FIG. 2 is a block diagram of example inputs and outputs of an automated anchor manager of FIG. 1.

[0012] FIG. 3 is a perspective view of an example automated windlass system of the USV of FIG. 1.

[0013] FIGS. 4a and 4b are perspective views of an example automated chain lock and release system of the USV of FIG. 1.

[0014] FIG. 5 is a perspective view of an example automated anchor port of the USV of FIG. 1.

[0015] FIG. 6 is a block diagram showing an example architecture of the automated anchor manager of FIG. 1.

[0016] FIG. 7 is an example screenshot generated by a user interface of the automated anchor manager of FIG. 1 and showing an example of anchor planning.

[0017] FIG. 8 is a flowchart showing an example method of operating the automated anchor manager of FIG. 1

[0018] FIG. 9 is a partial screenshot generated by the user interface of the automated anchor manager of FIG. 1 and showing an example of anchor monitoring.

DETAILED DESCRIPTION

[0019] Embodiments of the improved technique will now be described. One should appreciate that such embodiments are provided by way of example to illustrate certain features and principles but are not intended to be limiting.

[0020] An improved technique of managing an anchor in a surface vessel includes identifying, by a computer aboard the vessel, an anchor location within a designated geographical bounding box, by applying multiple filters configured to exclude regions within the bounding box based on respective filter conditions that are deemed unsuitable for anchoring. The technique further includes selecting a region not excluded by the filters and automatically dropping anchor in the selected region.

[0021] FIG. 1 shows an example surface vessel 100 with which embodiments of the improved technique can be practiced. As shown, the vessel 100 includes a hull 100a, an anchoring system 110, and an electronic system 120. The hull 100a has an anchor port 112 through which an anchor 114 of the anchoring system 110 may be dropped and retracted.

[0022] The electronic system 120 includes a computerized apparatus 130, which has one or more communication interfaces 132, a set of processors 134, and memory 140. The communication interfaces 122 include, for example, satellite, Wi-Fi, Bluetooth, Ethernet, CAN (Controller Area Network) bus, and/or other adapters for facilitating communications within the vessel 100 as well as with equipment and networks outside the vessel, such as with a control station (not shown) located remotely from the vessel 100. The processors 134 include one or more processing chips and/or assemblies, such as multiple CPUs (central processing units). The memory 140 includes both volatile memory, e.g., RAM (Random Access Memory), and non-volatile memory, such as one or more ROMs (Read-Only Memories), disk drives, solid state drives, and the like. The processors 134 and the memory 140 together form control circuitry, which is constructed and arranged to carry out various methods and functions as described herein. Also, the memory 140 includes a variety of software constructs realized in the form of executable instructions. When the executable instructions are run by the processors 134, the processors 134 are made to carry out the operations of the software constructs. Although certain software constructs are specifically shown and described, it is understood that the memory 130 typically includes many other software components, which are not shown, such as an operating system, various applications, processes, and daemons.

[0023] The electronic system 120 further includes various sensors, subsystems, and actuators, which may be distributed about the vessel 100. Examples of these sensors and actuators are as follows: [0024] Anchoring sensors and actuators 160, e.g., those involved in dropping, holding, or raising the anchor, or for cutting the anchor line in case of emergency. [0025] Oceanographic sensor(s) 162. [0026] Depth finder 164. [0027] GPS (Global Positioning Service) and/or GNSS (Global Navigation Satellite System) 166. [0028] AIS (Automatic Identification System)/Radar, e.g., for identifying other nearby vessels. [0029] Meteorological sensors 170, e.g., temperature, humidity, wind, weather forecasts. [0030] IMU (Inertial Measurement Unit) 172, for determining sea state (e.g., rough or calm). [0031] Hull sonar 174, e.g., for detecting nearby underwater objects.

[0032] Returning to the computerized apparatus 130, the memory 140 includes, i.e., realizes by execution of software instructions using associated data, an automated anchor manager (AAM) 150 and one or more electronic charts 154, such as may be provided by an Electronic Chart Display Information System (ECDIS). In an example, the AAM 150 is tasked with all aspects of anchor management, which include planning, executing, and monitoring anchoring activities. For planning anchoring activities, the AAM 150 is configured to fuse inputs from charts 154 and the above-described sensors and other data sources in selecting a suitable location for dropping anchor. For example, planning may be based on surface conditions (e.g., choppiness), weather conditions, whether there is sufficient space to anchor, whether water is of proper depth for anchoring, and whether seabed conditions are sufficient for anchoring. In an example, the AAM 150 applies filters 152 for excluding certain regions from being candidates for anchoring.

[0033] For executing a drop-anchor procedure, the AAM may obtain real-time measurements of the amount of anchor line released and of anchor line tension, which in some cases may include a direction of anchor line tension. The AAM 150 may further be configured to engage an anchor stop once a desired length of anchor line has been released. The AAM 150 may obtain similar measurements when raising the anchor. The AAM 150 may further be configured to release the anchor stop and to drive a windlass or an associated winch to lift the anchor 114 from the sea floor and to pull the anchor back to the vessel 100.

[0034] For monitoring anchoring conditions, the AAM 150 may track weather and sea surface conditions, check whether the anchor 114 is dragging on the seafloor, check whether other ships have entered the vicinity of the vessel 100, and monitor any other factors that may call for raising the anchor, releasing more anchor line, or retracting some anchor line. The AAM 150 may further react to emergencies. Reactions may include, for example, activating an emergency release if the anchor stop fails to release on its own, and directing a saw to cut through the anchor line in the unlikely event that the anchor 114 becomes stuck and cannot be raised.

[0035] FIG. 2 shows example anchoring sensors and actuators 160 in greater detail. Sensors may include a windlass encoder 210, e.g., an optical encoder or other type of encoder mounted to an axis of a drum of the windlass. As the drum rotates to dispense or retract anchor line, the encoder 210 measures the rotation and sends a signal representing the rotation to the AAM 150, which translates the rotation into a corresponding length of anchor line. In this manner, a precise length of anchor line dispensed or retracted can be determined. For example, the AAM 150 may direct the windlass to dispense a predetermined length of anchor line and may monitor the actual length of line dispensed in real time. When the length of line dispensed reaches a preset length, the AAM 150 may direct the windlass to stop and may activate an anchor-line stop to prevent the anchor line from continuing to pay out passively.

[0036] The anchoring sensors may further include a capstan encoder 220, e.g., an encoder coupled to an axis of a capstan drum placed in line with the windlass. In an example, the capstan encoder 220 works the same way as the windlass encoder 210 and may serve as a check of the windlass encoder 210. For example, the anchor line may occasionally slip on the windlass and/or capstan. By comparing rotations from the two encoders, the AAM 150 may detect the slippage and make adjustments to its representation of dispensed length. In some examples, only a single encoder is provided, which may be either the windlass encoder 210 or the capstan encoder 220.

[0037] The sensors may further include a sensor for measuring line tension 230. In an example, line tension may be measured based on input from one or more load cells coupled to the anchor port 112. As another example, line tension may be measured indirectly by monitoring electrical current drawn by the windlass or an associated winch. For example, the current drawn by the windlass/winch to resist the line tension may be proportional to the line tension itself, such that line tension may be calculated from measurements of current drawn.

[0038] One or more line-stop sensors 240 may be provided for measuring the position of an anchor-line stop, such as a rotatable pawl (FIG. 3). For example, measured positions may include an engaged position and a disengaged position, or it may include a measured angle of pawl rotation about an axis.

[0039] Regarding actuators, an anchor stop actuator 250 may be provided for moving the anchor stop (e.g., the pawl of FIG. 3) between the engaged position and the disengaged position. For example, the actuator 250 may include a stepper motor or other motor for rotating the pawl about its axis between the two positions. An anchor emergency stop release 260 may provide a secondary mechanism for releasing the anchor stop, e.g., if the pawl is stuck in the engaged position. An anchor line cutter 270 may be operated in other emergency situations, e.g., when the anchor 114 cannot be raised from the seafloor and the only available option is to cut the anchor line. A windlass torque/speed control 270 controls a rate and/or torque of rotation of the windlass when retracting anchor line. The control 270 may also be used when dispensing anchor line.

[0040] FIG. 3 shows an example windlass system that may be suitable for use with certain embodiments. Depicted in the figure are a windlass 310, a capstan 320, an automated line stopper 330, and an anchor line 340. The windlass, capstan, and line stopper are mounted to surface 302 of the vessel, such as a top deck or internal floor. In an example, both the windlass 310 and the capstan 320 are equipped with respective encoders (FIG. 2). Also, although the anchor line 340 is shown as taking only a single turn around drums of the windlass and capstan, the anchor line 340 may take numerous turns around the drum of each. The anchor 114 is not shown in the figure but would appear to the left, and a compartment for holding the anchor line 340 would appear to the right.

[0041] In an example, the line stopper 330 includes a rotatable pawl 350, which is shown in the disengaged (up) position in FIG. 3. The pawl 350 may be actuated by a motor 352, such as a stepper motor, which is configured to rotate the pawl 350 between up and down positions about an axis 354.

[0042] FIG. 4a shows the pawl 350 in the down (engaged) position. Here, it can be seen that the pawl 350 stops the anchor line 340 from advancing further to the left by pinning it against a disk 410. For example, the pawl 350 may include a channel 351 configured to capture a link of the anchor line 340. In this manner, the pawl 350 acts as a stop or brake, either allowing the anchor line 340 to pay out or to prevent it from doing so.

[0043] In some examples, the line stopper 330 includes an emergency release 360. For example, if the pawl 350 becomes stuck in the down (engaged) position and cannot be raised by the motor 352, the release 360 may act to lower the disk 410 (FIG. 4b), so that the anchor line 340 falls below the pawl 350 and becomes free. The line stopper 330 may then be reset by rotating the pawl 350 to the up position and raising the disk 410 back to the height shown in FIG. 4a. Preferably, all of these functions are performed automatically under control of the AAM 150.

[0044] In addition to limiting the amount of anchor line 340 dispensed, the line stopper 330 also serves the function of removing line tension from the capstan 320, the windlass 310, and the associated winch, which may be integrated into the windlass 310 or separate. With the line stopper 330 engaged, tension on the line 340 is borne by the line stopper 330, rather than by all of the other components, thus helping to preserve and protect those components.

[0045] FIG. 5 shows an example anchor port 112 in additional detail. Here, the anchor line 340 is shortened for illustrative purposes and is seen to extend from the line stopper 330, through the anchor port 112, and then to the anchor 114. The anchor port 112 is equipped with features that facilitate autonomous, crewless operation.

[0046] As shown in the magnified view to the right, the anchor port 112 includes a line cutter 510 and multiple load cells 540. The line cutter 510 operates under control of the AAM 150 and is configured to saw through the anchor line 340 in the event that the anchor 114 cannot be raised, such as when the anchor 114 becomes stuck under a reef or rock formation and the windlass/winch does not have sufficient power to lift it. A stuck condition may be identified, for example, by monitoring anchor tension (e.g., both magnitude and direction) when attempting to raise the anchor 114.

[0047] Anchor chains commonly include removable links that crewmembers can disconnect to release a stuck anchor. But removing links is typically not feasible in an automated scenario. Thus, to address the rare condition in which an anchor cannot be raised, the line cutter 510 is provided, e.g., at the mouth of the port 112, to saw through the anchor line 340.

[0048] In an example, the line cutter 510 is configured as a bandsaw and includes a blade 520, which may be a diamond wire, for example. The saw is configured to ride up and down under motor control on guides 530. Other arrangements are feasible, however, such as a chop saw or miter saw arrangement, where the saw is hinged on one side and rotates down about the hinge under motor control to cut through the line 340.

[0049] Load cells 540 may be provided at multiple locations around the anchor port 112 and may be positioned between the anchor port 112 and the hull 100a of the vessel 100 in such a manner that they bear forces imposed on the anchor port 112 by the anchor line 140. For example, a load cell 540 may be provided at the top, bottom, left, and right outer surfaces of the port 112 to measure forces in all relevant directions. Outputs from the load cells 540 are processed and sent to the AAM 150, which translates such outputs into measurements of both magnitude and direction of line tension. One should appreciate that the number and placement of load cells 540 as shown are intended merely for illustration and are not intended to be limiting.

[0050] FIG. 6 shows an example architecture of the AAM 150. In an example, the AAM 150 is built on a platform that supports robotic applications, such as the ROS2 open-source platform. In an example, the AAM 150 includes five nodes: an anchor node 610, a user interface (UI) node 620, a sense node 630, a communication node 640, and a mapping node 650. Each node is responsible for populating a set of topics, performing a function, and listening to other nodes. For example, the nodes 610-650 communicate via a publisher/subscriber (pub/sub) scheme wherein any node can publish information to a data distribution layer 660, from which other nodes that are configured as listeners/subscribers can obtain the data. For example, the sense node 630 may publish a value of current depth to the data distribution layer 660, and the map node 650, which is configured as a subscriber to this value, can obtain it. Example functions of the nodes are as follows: [0051] Anchor node 610 is responsible for publishing information about the anchor as well as executing any anchor-related commands. [0052] UI node 620 provides an interface to the AAM 150 for a potential human operator to engage in manual override, e.g., from a local or remote system. It listens to every topic on the ROS system and provides the user a visual of anchoring status across the planning (heat map of preferred anchoring locations-FIG. 7), executing (motor torques/positions, deployed line length), and monitoring (location relative to swing circle, chain location to stem) states. [0053] Sense node 630 produces data from sensors connected specifically to the anchoring system 110 and associated components and publishes the information. [0054] Communication node 640 is responsible for hosting communication with the vessel 100, collecting sensor and mission data, and publishing this information to other nodes. [0055] Mapping node 650 determines safe locations for anchoring, determines if there is a safety critical state when monitoring, and determines when the anchor node 610 should execute a drop-anchor procedure based on input from the sense and communication nodes.
One should appreciate that the modular, node-based architecture of the AAM 150 is easily extensible and can flexibly incorporate new sensors and capabilities.

[0056] For the AAM 150 to plan an anchor event, data is fused from AAM sources such as winch/windlass motor/encoder data, deck hardware sensors, vessel based sources, such as navigation (Global Navigation Satellite System (GNSS), Electronic Chart Display Information System (ECDIS)), vessel traffic sources (Automatic Identification System (AIS)), oceanographic, and meteorological data streams. Utilizing sources already equipped on the USV (via communication node 640) is highly advantageous requiring minimal additional sensors. In the event these sources are not readily available, provisions can be made to outfit a vessel for the collection of data required. For example, charting data may be replaced with high fidelity bottom scans or lower fidelity depth readings.

[0057] FIGS. 7 and 8 show an example arrangement for managing anchoring in a surface vessel, such as the vessel 100. FIG. 7 shows an example map view 700 that may be provided in certain embodiments, e.g., via the UI node 620. FIG. 8 shows an associated method 800. Although the map view 700 is illustrative of various aspects of the method 800, one should appreciate that certain embodiments may not present any map view, particularly in systems that are entirely automated.

[0058] The method 800 will now be described with reference to FIG. 7. Starting at 810, the AAM 150 receives a geographical bounding box 710 within which an anchor 114 of the surface vessel 100 is to be dropped. The bounding box 710 may be received from an external command center, or it may be received from another software component or system running within the vessel 100 itself. As shown, the bounding box 710 covers a portion of a larger map 702 and includes geographic features that may optimally be shown with color coding. The features include, for example, land 720, shallow water 730, deep water 740, and various regions that would intersect an expected swing circle of the vessel 100 once anchored. A swing circle is the area in which a vessel can drift once it is anchored and is typically represented as a circle around the anchoring point. Related to the swing circle is a quantity called scope, which refers to a ratio of anchor-line length to depth of the anchor. Region 750 depicts areas within which a scope of 15:1 would hit land. Regions 760 and 770 are regions within which the swing circle would enter shallow water (760) or would hit land (770). One should appreciate that the bounding box 710 and the various regions shown on the map may be represented in digital form and that visual representation may be optional.

[0059] At 820, a plurality of filters 152 (FIG. 1) is applied to the geographical bounding box 710. The filters operate to exclude regions within the geographical bounding box 710 at which conditions for anchoring are unsuitable. In an example, the AAM 150 renders the area within the bounding box 710 as a grid of rectangles 780 of uniform dimensions, such as 25-meters square, for example. The rectangles need not be squares, but they all preferably have the same dimensions. The AAM 150 then applies the filters 152 to the rectangles 780 within the bounding box 710 one filter at a time. For example, a first filter 152 excludes rectangles 780 that include any land 720, and a second filter 152 excludes rectangles 780 that include any shallow water 730. Although no shipping lanes are shown, another filter 152 may exclude rectangles that intersect shipping lanes. Still other filters 152 may exclude rectangles based on their intersections with expected swing circles. For example, a filter may exclude rectangles around which the vessel's swing circle would intersect land or shallow water, or may exclude rectangles for which an enlarged swing circle of 15:1 would intersect land or shallow water. One should appreciate that any number of filters 152 may be applied, and that the filters 152 may be applied in any order, including simultaneously.

[0060] After applying the filters 152 to the rectangles 780 within the bounding box 710, any rectangles 780 that have not been excluded by the filters remain candidates for anchoring. The AAM 150 may then select a particular, non-excluded rectangle as a selected region for anchoring. In an example, the AAM 150 preferably selects the rectangle surrounded by the largest area of deep water. The selected region is shown using reference 790, which depicts an expected swing circle around the selected region.

[0061] At 830, after the surface vessel 100 has navigated to the selected region, the AAM 150 electronically initiates a drop-anchor procedure to drop the anchor 114 automatically within the selected region. For example, the AAM 150 or another software component may direct the vessel 100 to travel to the selected region and to drop anchor there. The drop-anchor procedure is performed under control of the AAM 150. For example, the AAM releases the line stop 330 and allows the anchor 114 to fall passively or under rate control by the windlass/winch until a preset amount of anchor line 340 is released. Once the preset amount is reached, the AAM 150 may direct the line stop 330 to engage, e.g., by rotating the pawl 350 to the down position. The anchor line 340 is then locked in place.

[0062] While the vessel 100 is anchored, the AAM 150 may continue to monitor conditions within and around the vessel and take corrective actions when necessary. For example, the AAM continues to monitor other ships in the vicinity, weather conditions, sea surface conditions, and the vessel's actual location. If another ship enters the vessel's swing circle, the AAM 150 may raise the anchor 114 and select a new location for anchoring. If the weather or surface conditions deteriorate, the AAM 150 may let out more anchor line 340, assuming a larger swing circle would not intersect any obstacles. The AAM 150 may also monitor for anchor drag.

[0063] FIG. 9 shows an example screen display depicting anchor drag. Here, an anchor location selected by the AAM 150 is shown by reference 910, with reference 912 depicting the swing circle around the selected location 910. While the vessel 100 is anchored, the AAM 150 continues to monitor the vessel's location, e.g., using GPS and/or GNSS. Anchor location 920 depicts an expected anchoring error. For example, location 920 (with its swing circle 922) are at the edge of acceptable error. Although small errors are expected, large errors may indicate anchor drag, i.e., the anchor 114 failing to embed securely in the seafloor. Targets 930 show example vessel locations that are still within expected tolerances, while target 940 indicates an error, as the vessel 100 could not drift to that location unless the anchor was dragging. Detection of the vessel 100 being outside the expected range may result in an alert 950. In an example, the AAM 150 responds to the alert by raising the anchor 114 and attempting to restart the drop-anchor procedure. The AAM 150 may select a new region for this purpose, using the method 800, under the assumption that the seafloor may be unsuitable for anchoring at the originally selected location.

[0064] An improved technique has been described of managing an anchor 114 in a surface vessel 100. The technique includes identifying, by a computer 130 aboard the vessel 100, an anchor location within a designated geographical bounding box 710 by applying multiple filters 152 configured to exclude regions within the bounding box 710 based on respective filter conditions that are deemed unsuitable for anchoring. The technique further includes selecting a region 790 not excluded by the filters 152 and automatically dropping anchor in the selected region.

[0065] Having described certain embodiments, numerous alternative embodiments or variations can be made. For example, although embodiments have been described in connection with uncrewed vessels, they may also be used with crewed vessels, e.g., to automate or facilitate the anchoring process. Also, although embodiments have been described that involve surface vessels, this does not suggest that such vessels are limited only to surface operation. For example, embodiments may include submarines that temporarily operate on a sea surface or amphibious vehicles capable of traveling on both land and sea.

[0066] Further, although features have been shown and described with reference to particular embodiments hereof, such features may be included and hereby are included in any of the disclosed embodiments and their variants. Thus, it is understood that features disclosed in connection with any embodiment are included in any other embodiment.

[0067] Further still, the improvement or portions thereof may be embodied as a computer program product including one or more non-transient, computer-readable storage media, such as a magnetic disk, magnetic tape, compact disk, DVD, optical disk, flash drive, solid state drive, SD (Secure Digital) chip or device, Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), and/or the like (shown by way of example as medium 850 in FIG. 8). Any number of computer-readable media may be used. The media may be encoded with instructions which, when executed on one or more computers or other processors, perform the process or processes described herein. Such media may be considered articles of manufacture or machines, and may be transportable from one machine to another.

[0068] As used throughout this document, the words comprising, including, containing, and having are intended to set forth certain items, steps, elements, or aspects of something in an open-ended fashion. Also, as used herein and unless a specific statement is made to the contrary, the word set means one or more of something. This is the case regardless of whether the phrase set of is followed by a singular or plural object and regardless of whether it is conjugated with a singular or plural verb. Also, a set of elements can describe fewer than all elements present. Thus, there may be additional elements of the same kind that are not part of the set. Further, ordinal expressions, such as first, second, third, and so on, may be used as adjectives herein for identification purposes. Unless specifically indicated, these ordinal expressions are not intended to imply any ordering or sequence. Thus, for example, a second event may take place before or after a first event, or even if no first event ever occurs. In addition, an identification herein of a particular element, feature, or act as being a first such element, feature, or act should not be construed as requiring that there must also be a second or other such element, feature or act. Rather, the first item may be the only one. Also, and unless specifically stated to the contrary, based on is intended to be nonexclusive. Thus, based on should be interpreted as meaning based at least in part on unless specifically indicated otherwise. Although certain embodiments are disclosed herein, it is understood that these are provided by way of example only and should not be construed as limiting.

[0069] Those skilled in the art will therefore understand that various changes in form and detail may be made to the embodiments disclosed herein without departing from the scope of the following claims.

TABLE-US-00001 TABLE or Reference Numerals Reference No. Description 100 Uncrewed Surface Vessel (USV) 110 Anchoring system 112 Anchor port, through which anchor passes 114 Anchor 120 Electronic system 130 Computerized apparatus 132 Communications interface(s), e.g., satellite, Wi-Fi, Bluetooth, etc. 134 One or more processors 140 Memory, including both volatile and non-volatile memory 150 Automated Anchor Manager (AAM) 152 Filters, e.g., used by AAM to exclude regions from being candidates for anchoring 154 Electronic chart(s), e.g., Electronic Chart Display Information System (ECDIS) 160 Anchoring sensors and actuators, e.g., windlass motor current, windlass encoder, capstan encoder, windlass motor driver, anchor stop actuator and release, anchor-line load cells. 162 Data feed(s) from oceanographic sensor(s) 164 Data feed from depth finder 166 GPS (Global Positioning Service) and/or GNSS (Global Navigation Satellite System) 168 AIS (Automatic Identification System)/Radar, for identifying other nearby vessels 170 Data feed from meteorological sensors (e.g., temperature, humidity, wind, weather forecasts) 172 IMU (Inertial Measurement Unit)/Sea State, for identifying rough seas, calm seas, etc. 174 Hull sonar; e.g., for detecting nearby underwater objects. 210 Windlass encoder, e.g., measures rotations of windlass; enables computer to determine length of anchor line dispensed 220 Capstan encoder; e.g., measures rotations of capstan drum; enables computer to determine length of anchor line dispensed and serves as a check of windlass encoder, e.g., to determine slip or skipping. 230 Anchor line tension, e.g., determined based on current drawn by winch/windlass motor. 240 Anchor line stop sensor(s), e.g., angle of pawl used to lock anchor line 250 Anchor stop actuator, e.g., control signal that directs pawl to move between stop position and release position 260 Anchor stop emergency release 270 Line cutter; e.g., control signal that directs saw to cuts through anchor line in case of emergency. 280 Windlass torque/speed control, e.g., control signal that controls speed and/or torque of windlass winch. 302 Horizontal surface of vessel; such as top deck or floor of internal region 310 Windlass/winch system, e.g., equipped with encoder on transverse axis 320 Capstan, e.g., equipped with encoder on transverse axis 330 Automated line stopper 340 Anchor line, e.g., chain, cable, or combination thereof 350 Anchor line stop, e.g., rotatable pawl that engages or releases anchor line. 351 Channel of pawl 352 Pawl motor 354 Pawl axis 360 Pawl emergency release, e.g., pulls down on disk 410 Disk, e.g., drops for emergency release of pawl 510 Automated chain cutter, e.g., band saw in guillotine or miter-saw arrangement 520 Cutting cord, e.g., diamond wire 530 Guide rods 540 Load cells (e.g., x4) 610 Anchor node 620 UI (User Interface) node 630 Sense node 640 Communication node 650 Map node 660 Data Distribution Layer 700 Screen shot of planning phase 702 Map of area containing bounding box 710 Bounding box providing candidate regions for anchoring 720 Land 730 Shallow water 740 Deep water 750 Increasing scope to 15:1 would hit land 760 Swing circle would enter shallow water. 770 Swing circle would hit land 780 Rectangles forming grid on map 790 Swing circle around selected location 800 Method of managing anchoring 810, 820, 830 Acts of method 800 850 Computer-program product 910 Planned anchor location 912 Planned swing circle 920 Actual anchor location 922 Actual swing circle 930 Previous vessel locations 940 Vessel location at drag alarm 950 Drag alarm indicator