NO342704B1 - System for monitoring load on mooring lines of floating installations - Google Patents
System for monitoring load on mooring lines of floating installations Download PDFInfo
- Publication number
- NO342704B1 NO342704B1 NO20161116A NO20161116A NO342704B1 NO 342704 B1 NO342704 B1 NO 342704B1 NO 20161116 A NO20161116 A NO 20161116A NO 20161116 A NO20161116 A NO 20161116A NO 342704 B1 NO342704 B1 NO 342704B1
- Authority
- NO
- Norway
- Prior art keywords
- mooring lines
- mooring
- lines
- indicators
- load
- Prior art date
Links
- 238000009434 installation Methods 0.000 title claims abstract description 26
- 238000012544 monitoring process Methods 0.000 title claims abstract description 9
- 241000251468 Actinopterygii Species 0.000 claims description 7
- 238000009372 pisciculture Methods 0.000 description 8
- 238000006073 displacement reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 238000004873 anchoring Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K61/00—Culture of aquatic animals
- A01K61/60—Floating cultivation devices, e.g. rafts or floating fish-farms
- A01K61/65—Connecting or mooring devices therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B2021/003—Mooring or anchoring equipment, not otherwise provided for
- B63B2021/008—Load monitors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
- B63B2021/505—Methods for installation or mooring of floating offshore platforms on site
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/80—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in fisheries management
- Y02A40/81—Aquaculture, e.g. of fish
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Environmental Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Marine Sciences & Fisheries (AREA)
- Zoology (AREA)
- Animal Husbandry (AREA)
- Biodiversity & Conservation Biology (AREA)
- Selective Calling Equipment (AREA)
Abstract
The invention relates to a system for monitoring load in mooring lines of a floating installation, comprising a number of position indicators being connected to the installation or the mooring lines. Each position indicator has a transmitter for transmitting its position to a control unit and movement of the position indicators reflect load on the corresponding mooring lines. Movement of one or more indicators beyond a predetermined limit results in a report being sent to an operator.The invention relates to a system for monitoring load in mooring lines of a floating installation, comprising a number of position indicators being connected to the installation or the mooring lines. Each position indicator has a transmitter for transmitting its position to a control unit and movement of the position indicators reflects load on the corresponding mooring lines. Moving one or more indicators beyond a predetermined limit results in a report being sent to an operator.
Description
Technical field
The present invention concerns a system for monitoring the mooring lines of floating installations, for instance of a fish farm.
Background
There are a number of floating installations ranging from small private floating rafts to fish farming plants and oil drilling installations, which are anchored at the seabed but floating at or in the water. In most cases it is not possible to supervise the condition of the mooring lines at all times, and in order to avoid dangerous situations where the floating installations may break away, the lines must be inspected regularly, and after specific situations especially. In most cases it is used ROVs or scuba divers to inspect the mooring lines, or, when possible, the mooring lines are raised above the water line.
Trained scuba divers may not be available at all times, and it may be both expensive and time consuming to wait for them to arrive at the installation. ROVs are expensive to use and are normally operated by specially trained persons. US 6481387 and EP 0315561 describes systems and methods for positioning of fish farming plants, however they are not stating the condition of the mooring lines.
The tension in a mooring system may be measured by strain sensors connected directly as a part of the mooring component, and will measure the strain and thereby giving the tension. In WO 200/129323 it is described a method for monitoring damage to or failure of a mooring system comprising mooring lines of a moored vessel. The method involves determining the geographical position of a locating point on the vessel. However, for a more complex mooring system as for fish farms which consists of up to 200 individual components, one would need as many sensors as components to monitor the tension of the whole mooring system. The sensors need power that is usually supplied through cables that will complex the system even more.
The main object of the invention is thus to provide a system for monitoring the mooring lines real-time, and to identify any lines needing inspection. Further there is an object that the system should identify a possible overload and/or predict fatigue lifetime expectancy in the mooring lines in order to reinforce or replace the mooring lines in question. Another object is to provide a system having low maintenance and which may be easily replaced upon breakage. Yet another object is that is should be easy to install even on existing farms.
The invention
The above said objects are met by a system according to patent claim 1, and further features are stated in the independent claims.
The invention is related to a system for monitoring load in mooring lines of a floating installation, comprising a number of position indicators being connected to the installation or the mooring lines, each position indicator has a transmitter for transmitting its position to a control unit, wherein movement of the position indicators reflect movement of the installation and thus load on the corresponding mooring lines. The position of each indicator is received in a control unit, a pattern of indicators of the mooring system is identified, any deviations from a predetermined optimal pattern is calculated, and deviations above a given limit is reported to an operator.
By "position indicator" it is herein meant any unit identifying its position and having a transmitter for transmitting its position, such as a GPS unit. The transmitter may be transmitting directly to an external receiver, or to a receiver on the installation which in turn transmits the positions of a number of units to an external receiver. The receiver is preferably a control unit, such as a computer, and the positions are preferably transmitted real time.
The position indicator may be connected directly to a mooring line, and/or to a part of the installation. If the indicator is connected to a part of the installation, movement of the indicator may reflect load on several mooring lines. Correspondingly, if the indicator is arranged at a juncture of mooring lines, such as a juncture in a mooring grid of a fish farming plant, movement of the indicator may reflect load on several mooring lines.
By "mooring line" it is herein meant the whole mooring, including but not limited to anchor or bolt being secured to the seabed, shackles, chains, thimbles, ropes, mooring plates and even the buoy at the sea surface. A mooring line may also be a part of a mooring system, not running to the sea bed, such as but not limited to, a part of a grid in a grid mooring. By "corresponding mooring lines" it is herein meant the mooring lines being affected when the position indicator moves.
The position of each indicator is received in a control unit, and deviation from a predetermined optimal position is calculated. The load on mooring lines corresponding to the position indicator, can be calculated based on this position deviation. The calculations are based on the tension-displacement characteristics of a mooring line, for instance may a numerical computer program be used for generating dynamic tension-displacement characteristics of the mooring system for floating installations. The measured displacements are set as displacement boundary conditions for a numerical model and the tension loads in mooring are determined when the model has found an equilibrium state for the deformed pattern. This will be obvious to a person skilled in the art. If the load on a mooring line is beyond a predetermined limit, a report is given.
In a preferred embodiment, the mooring lines are below water, and the position indicators are arranged above water, attached to the mooring lines by a line. The "optimal position" of each position indicator is then the position where the mooring lines are at a minimum load, and the position indicator is straight above the attachment point. As the position indicator is floating on water, it may move within a given radius without indicating movement of the mooring lines at the attachment point, in the following this radius is referred to as "free radius". The size of the free radius depends on the depth of the mooring lines, and the length of the attachment line. Movement outside this free radius reflects movement of the mooring lines.
The deviation from the optimal position is calculated, and deviations being larger than a given limit, are reported. The "given limit" is based on a number of factors, such as the size of the free radius, the size of the deviation, the strength of the mooring line and mooring in question, how long time the deviation lasts, etc. There might also be several types of reports, reporting different levels of deviations, reflecting different levels of severity for the mooring of the installation. This will be obvious to a person skilled in the art of programming.
The position indicators are arranged at the mooring lines in a pattern, and the pattern reflects the mooring situation of the installation as such. This means that if the pattern is broken, some mooring lines may be overloaded and needs to be inspected even if the position of the position indicator at this mooring line is not beyond the given limit. Thus when the position of each indicator is received in the control unit, a pattern of indicators of the mooring system is identified, and any deviation from a predetermined optimal pattern is calculated, and deviations above a given limit is reported.
According to the invention, a report is given when a position of a position indicator is deviating beyond the optimal position within a given patter, or when the whole pattern is deviating beyond a given limit from the optimal position of the patter. The deviations are preferably reported by sending a signal to an operator.
The system according to the invention may be used for monitoring load in mooring lines of fish farming plant, wherein the fish farms are moored with a grid system. The position indicators may preferably be connected to junctures in the grid system, for instance every juncture, or at the least one juncture in every grid.
In a preferred embodiment, the control unit comprises a storage medium, wherein the movement of each position indicator and pattern of position indicators are stored for later analysis. In this way an operator is able to go back in time and see the movements of the installation, and the load of the mooring lines calculated from the movement of the position indicators. This may for instance be especially interesting after a storm, or if a boat or other vessel have been in touch with the installation.
Further, it is preferred to visualise the measurements for an operator, indicating both current load and also load over time, being aggregated time. If the installation is intact and also under uniform load, for instance due to wind, the geometry of the installation or the pattern of position indicators, may be maintained. In this case the current load on the mooring lines must be indicated based on displacement of each position indicators from the optimal position.
Mooring lines are certified by the manufacturer for a certain endurance of continuous critical load. Normally, the lines withstand less load if the load lasts long. Thus, it is also important to measure time beyond critical levels, and this should also be stored in the control unit, and preferably reported along with the load. If the mooring lines are loaded beyond their breaking point there may be damage to mooring lines. Some or all affected lines may be torn, and the geometry of the installation may no longer intact, leaving adjacent mooring lines to take up even greater load. Such a condition will be indicated as one or more position indicators are no longer at their optimal position.
When the control unit has a storage medium, the system may calculate fatigue lifetime expectancy for the mooring line components, for instance steal chain elements. The fatigue lifetime is calculated based on change in tension level over time. Material tear can be estimated on a chain based on the predicted dynamic movement and friction force between each connecting chain component. When the remaining lifetime is less than a predetermined level, a report may be given.
Since a change in wind direction may possibly restore geometry to within a predetermined limit, it is also preferred to flag past events in the event of operator absence. It is also preferred to determine aggregated non-continuous time above critical load, to identify mooring lines that require more frequent inspections or possibly further reinforcements.
The system calculates the load on any given component of the mooring based on the global displacement / offset of the components that are measured. The accuracy relies on number of measurement points and where they are placed. Based on experience from observations a typical mooring system for a fish farm would need 4 to 18 measurement points. A floating installation moored to seabed would typically need 1 to 3 measurement points. This depends on the size of the plant or installation and the dynamic movement in sea.
Description of the figure
The invention will now be described with the help of the enclosed Figures, showing a system according to the present invention arranged to monitor the mooring lines of a fish farming plant. The different parts of the figure are not necessarily in scale to each other, as the diagram is merely for illustrating the invention.
The following description of an exemplary embodiment refers to the drawings, and the following detailed description is not meant or intended to limit the invention. Instead, the scope of the invention is defined by the appended claims.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The present invention will now be described, by way of example only, with reference to the following diagrams wherein:
Figure 1 shows a fish farming plant, and
Figure 2 shows the load on the mooring lines of a fish farming plant.
Description of preferred embodiments of the invention
Figure 1 shows a fish farming plant having six net cages 1, all moored with a grid 2 in a well known matter. Each net cage is moored to the grid by eight lines 3, and the grid is moored to the seabed by fourteen anchoring or mooring lines 4. At each junction of the grid, there is arranged a buoy 5, and on each buoy there is arranged a position indicator, in total twelve indicators.
Each position indicator transmit its position to a control unit (not shown), which calculates the deviation of each point from the optimal point, and the deviation from the pattern, if any. Then the control unit calculates the load on the mooring lines, based on the present position of the position indicator, and information regarding the optimal position of each indicator. A picture showing the load on the different mooring lines are shown in Figure 2. As the position indicators are arranged on a buoy 5 connected to a junction of the grid 2, movement of one indicator may reflect load on several mooring lines.
When for instance wind or current comes from the left in Figure 1, all buoys 5 will move to the right to the end of their free radius, that is until the lines holding the buoys are stretched. If the wind is sufficiently strong, the fish nets and the whole plant may move to the right, and the mooring lines 4 become more loaded. Since the position indicators are deviating from their optimal position by more than their free radius, a report will be issued, even if the pattern of indicators is not broken. If some parts of the plant move more then the rest of the plant, the corresponding mooring lines may be overloaded. The pattern of indicators will be broken, and the control unit will send a second report to the operator in charge.
In Figure 2 it is shown a situation where some mooring lines are broken due to overload. The neighbouring lines will also be overloaded since they must compensate for the missing line. In this case several reports may be issued from the control system, as several position indicators are deviating from their optimal position, and the pattern is broken. In the shown figure the lines are coloured blue, green, yellow and red, indicating the severity of the report.
When this is performed real-time with storage, it is possible for an operator to strengthen lines being subjected to too large forces over too long time. Further, when a report is issued, the operator will know which mooring lines that needs to be inspected, and possibly to replace damaged or broken lines before more lines break, and thus the danger for a total breakdown is substantially reduced.
Claims (6)
1. System for monitoring load in mooring lines of a floating installation, comprising a number of position indicators being connected to the installation or the mooring lines, each position indicator has a transmitter for transmitting its position to a control unit wherein movement of the position indicators reflect load on the corresponding mooring lines, characterized in that the position of each indicator is received in a control unit, a pattern of indicators of the mooring system is identified, and any deviation from a predetermined optimal pattern is calculated, and deviations above a given limit is reported to an operator.
2. System according to claim 1, characterized that the control unit has a storage for storing movement of the position indicators
3. System according to claim 1 or 2, characterized in that the position is transmitted real time.
4. System according to any one of the preceding claims, characterized in that the position of each indicator is received in a control unit, and the deviation from a predetermined optimal position is calculated, and deviations above a given limit is reported.
5. System according to any one of the preceding claims, characterized in that the deviations are reported by sending a signal to an operator.
6. Use of a system according to any one of the preceding claims, for monitoring mooring lines of a fish farm, wherein the fish farm is moored with a grid system and position indicators are connected to each juncture in the grid system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20161116A NO342704B1 (en) | 2016-07-05 | 2016-07-05 | System for monitoring load on mooring lines of floating installations |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20161116A NO342704B1 (en) | 2016-07-05 | 2016-07-05 | System for monitoring load on mooring lines of floating installations |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| NO20161116A1 NO20161116A1 (en) | 2018-01-08 |
| NO342704B1 true NO342704B1 (en) | 2018-07-16 |
Family
ID=60997140
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NO20161116A NO342704B1 (en) | 2016-07-05 | 2016-07-05 | System for monitoring load on mooring lines of floating installations |
Country Status (1)
| Country | Link |
|---|---|
| NO (1) | NO342704B1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO345259B1 (en) | 2018-06-12 | 2020-11-23 | Kahrs Hansen As | Instrumentation system for integrity monitoring of a net barrier |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2133151A (en) * | 1983-01-05 | 1984-07-18 | Shell Int Research | Surveying positions of mooring lines |
| WO2007081221A1 (en) * | 2006-01-16 | 2007-07-19 | Fobox As | Mooring system |
| WO2008129323A1 (en) * | 2007-04-19 | 2008-10-30 | Ocean Technical Services Limited | Vessel mooring monitor |
-
2016
- 2016-07-05 NO NO20161116A patent/NO342704B1/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2133151A (en) * | 1983-01-05 | 1984-07-18 | Shell Int Research | Surveying positions of mooring lines |
| WO2007081221A1 (en) * | 2006-01-16 | 2007-07-19 | Fobox As | Mooring system |
| WO2008129323A1 (en) * | 2007-04-19 | 2008-10-30 | Ocean Technical Services Limited | Vessel mooring monitor |
Also Published As
| Publication number | Publication date |
|---|---|
| NO20161116A1 (en) | 2018-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2020204051B2 (en) | System and method for providing information on fuel savings, safe operation, and maintenance by real-time predictive monitoring and predictive controlling of aerodynamic and hydrodynamic environmental internal/external forces, hull stresses, motion with six degrees of freedom, and the location of marine structure | |
| JP5762565B2 (en) | Mooring line cutting detection device and detection method for floating wind turbine equipment, and floating wind turbine equipment | |
| JP6463028B2 (en) | Load / stress monitoring method for floating facilities and load / stress monitoring system for floating facilities | |
| US5284452A (en) | Mooring buoy with hawser tension indicator system | |
| NO20141378A1 (en) | Stretch-anchored cage | |
| GB2560074A (en) | Offshore wind farm management system and method thereof | |
| CN112325859A (en) | Floating seabed base | |
| CN114705342A (en) | Wharf boat wharf cable stress real-time monitoring and safety early warning system and method | |
| Wang et al. | On the monitoring of mooring system performance | |
| NO342704B1 (en) | System for monitoring load on mooring lines of floating installations | |
| Venkatesan et al. | Reliability analysis and integrity management of instrumented buoy moorings for monitoring the Indian Seas | |
| Hageman et al. | Integrity management of mooring systems | |
| Votsis et al. | Review of technologies for monitoring the performance of marine structures | |
| Viselli et al. | VolturnUS 1: 8: conclusion of 18-months of operation of the first grid-connected floating wind turbine prototype in the Americas | |
| Lugsdin | Real-time monitoring of FPSO mooring lines, risers | |
| EP3391742B1 (en) | Mooring plate for fish farm | |
| CN114151292A (en) | On-line monitoring system and method for foundation scouring of offshore wind generating set | |
| KR101358787B1 (en) | Monitoring system for line-equipment of underwater | |
| KR20080092489A (en) | Realtime monitoring system for mooring facilities in a harbor | |
| Nordgård-Hansen et al. | Condition monitoring and maintenance for fibre rope moorings in offshore wind | |
| CN118715158A (en) | Device for monitoring at least one anchor line of a floating support | |
| BR102013007957B1 (en) | WIRE MONITORING SYSTEM FOR FLEXIBLE DUCT TRAIN ARMATURE AND APPLICATION METHOD | |
| Eassom et al. | Detection of Long-Term Changes in Mooring Stiffness Using Vessel Position Monitoring | |
| Michailides et al. | Monitoring the response of connected moored floating modules | |
| Vignoli et al. | Monitoring and dynamic identification of Vega-A platform |