Ship monitoring systems and ships

Abstract

The present invention aims to provide a ship monitoring system and a ship that enable shippers and lenders to manage the effectiveness of GHG emission reduction (utilizing specific ships for shipping) and collateral value (quality of ship operation) using quantitative and reliable indicators. This problem is solved by providing a processing device 20 that receives, stores, and analyzes output signals from the ship 1. The processing device 20 calculates the initial and ongoing propeller efficiency and drag coefficient based on the collected thrust values, ship speed, or propulsion engine output. It also calculates the difference between the initial and ongoing propeller efficiency and drag coefficient, quantifies and records / analyzes the temporary and unavoidable factors from the difference, and identifies or predicts the factors that affect changes in the drag coefficient and propeller efficiency.

Description

Technical Field

[0001] The present invention relates to a ship monitoring system and a ship, and more specifically, to a ship monitoring system and a ship suitable for monitoring the energy efficiency and GHG (greenhouse gas) emissions of cargo transport ships whose propellers are directly connected to the engine.

Background Art

[0002] In recent years, regulations on GHG emissions have been tightened, and fuel efficiency reduction has been accompanied by growing social and economic motivations that exceed the cost of fuel expenses.

[0003] In the financing of shipowners and cargo owner enterprises, due to the strong interest of investors (shareholders) and lenders (banks) in environmental protection, and the progressive and further promoted introduction of regulations through economic measures such as regulations and surcharges, the motivation to improve the energy efficiency of maritime transport through operations has been strengthened. That is, cargo owners who entrust operations to the maritime transport industry (ESG investment; ESG reports) and financial institutions that provide funds (the Poseidon Principles) have strengthened their motivation to monitor the reduction of GHG emissions from ships. Here, ESG investment refers to funds for which investment eligibility is determined using environment-friendly corporate governance and business operations as indicators, and financial institutions that have signed the Poseidon Principles are required to quantitatively evaluate the degree of alignment of their own ship financing portfolios with the IMO targets for GHG emission reduction from international shipping, and to publish the results of the evaluation.

Prior Art Document

Patent Document

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

[0005] Conventionally, various technological developments have been made to suppress GHG emissions, such as reducing air resistance (Patent Document 1), optimizing trim (Patent Document 2), and developing auxiliary thrust sails (Patent Documents 3, 4, 5, and 6).

[0006] It is certainly conceptually understandable that a reduction in hull resistance leads to a decrease in fuel consumption, and that hull resistance suppresses the ship's thrust. However, there are various factors that affect thrust suppression, and these factors are intricately intertwined and do not affect fuel efficiency fluctuations. As a result, optimizing and calculating the effectiveness of the developed technologies mentioned above is currently difficult.

[0007] The deterioration of a ship's energy efficiency, or worsening of its fuel consumption, is mainly due to increased hull resistance caused by increased viscous resistance resulting from the attachment of organisms to the hull and the resulting decrease in smoothness, and decreased propeller efficiency due to the attachment and erosion of organisms to the propellers.

[0008] Other factors that contribute to poor fuel efficiency include hull motion, sleighing (a condition where the direction of the ship's movement differs from the direction of its bow), rudder resistance and sleighing due to steering, differences in draft depth, and differences in trim angle, all of which affect the efficiency of the hull.

[0009] These factors contributing to the decrease in efficiency are intertwined and difficult to separate, and furthermore, methods for individually evaluating the aforementioned increase in resistance and decrease in propeller efficiency have not been elucidated, making it impossible to utilize this information in ship operations.

[0010] In recent years, as mentioned in the background above, the environmental aspects of energy efficiency in shipping have attracted attention, and inefficient fuel use has led to the introduction of regulations and penalties such as charges, creating economic risks. From the perspective of shippers and lenders, it is desirable to be able to manage the effectiveness of GHG emission reduction (using specific vessels for shipping) and the management of collateral value (the quality of vessel operation) using quantitative and reliable indicators.

[0011] While it might be possible to address the aforementioned risks by sequentially monitoring and individually quantifying the increased drag and decreased propeller efficiency, conventional methods have proven insufficient.

[0012] In addition to the factors mentioned above, changes in fuel consumption are also influenced by unavoidable ocean conditions (wind and waves), ocean currents, and tidal currents. However, these unavoidable factors presented a problem: the lack of established methods to separate and explain them meant that the resulting decrease in efficiency could not be easily explained.

[0013] Furthermore, while quantifying energy efficiency is desirable as part of environmental conservation efforts in corporate activities, conventional methods have the problem of not being able to isolate unavoidable factors that worsen efficiency, such as the inevitable decrease in efficiency due to rough weather on the Pacific shipping route in winter (Bering Sea).

[0014] The object of the present invention is to provide a ship monitoring system and a ship that enable continuous estimation of the factors causing deterioration in the energy efficiency of a ship. Another objective of the present invention is to provide a ship monitoring system and a ship that can isolate factors affecting the energy efficiency of a ship due to ocean conditions and ship operations. Furthermore, another objective of the present invention is to provide a ship monitoring system and ships that enable shippers and lenders to manage the effectiveness of GHG emission reduction (using specific ships for shipping) and the management of collateral value (the quality of ship operations) using quantitative and reliable indicators.

[0015] Furthermore, other problems of the present invention will become clear from the following description. [Means for solving the problem]

[0016] The above problems are solved by the respective inventions described below.

[0017] 1. A marine vessel monitoring system comprising a processing device that receives, stores, and analyzes output signals from a marine vessel, wherein the processing device calculates the propeller efficiency and the resistance coefficient in the initial stage and during navigation based on the collected thrust value, vessel speed, or propulsion engine output, calculates the difference between the initial stage and during navigation for the propeller efficiency and the resistance coefficient, quantifies, records, and analyzes each of the temporary factors and unavoidable factors from the difference, and identifies or predicts the factors affecting the changes in the resistance coefficient and the propeller efficiency. 2. The marine vessel monitoring system according to claim 1, wherein the marine vessel further comprises a thrust measurement device, and the thrust value is received from the thrust measurement device. 3. The marine vessel monitoring system according to claim 1, wherein the propeller efficiency and the resistance coefficient in the initial stage are selected from a state in still water without acceleration or deceleration of the hull, a sea trial, or a test after maintenance in a dock. 4. The marine vessel monitoring system according to claim 1, further performing separation of some of the factors affecting the propeller efficiency and the resistance coefficient. 5. The marine vessel monitoring system according to claim 4, wherein the part of the factors to be separated is the unavoidable factor, and fouling of the marine vessel or wear of the propeller is extracted from the propeller efficiency and the resistance coefficient after separation. 6. A marine vessel comprising the marine vessel monitoring system according to any one of claims 1 to 5. Effects of the Invention

[0018] According to the present invention, it is possible to provide a marine vessel monitoring system and a marine vessel that enable continuous estimation of the cause of changes in the energy efficiency of the marine vessel. Furthermore, according to the present invention, it is possible to provide a ship monitoring system and a ship that can isolate factors that affect the energy efficiency of a ship due to the influence of sea conditions and ship operations. Furthermore, according to the present invention, it is possible to provide a ship monitoring system and ships that enable shippers and lenders to manage the effectiveness of GHG emission reduction (using specific ships for shipping) and the management of collateral value (quality of ship operation) using quantitative and reliable indicators. [Brief explanation of the drawing]

[0019] [Figure 1] This diagram illustrates one embodiment of the device configuration of the ship monitoring system of the present invention. [Figure 2] This figure shows an example of the processing flow of the ship monitoring system of the present invention. [Figure 3] Perspective view showing an example of a strain sensor mounting location on a ship's crankcase. [Figure 4] An explanatory diagram showing another embodiment of the device configuration of the ship monitoring system of the present invention. [Modes for carrying out the invention]

[0020] Figure 1 is an explanatory diagram showing one embodiment of the device configuration of the ship monitoring system of the present invention.

[0021] As shown in Figure 1, the ship monitoring system of the present invention includes a thrust measuring device 3 for measuring the thrust of the ship's propeller. The ship's hull 1 is equipped with a main propulsion engine 2, which is connected to a propeller 5 via a propulsion shaft (propeller shaft) 4, and the propeller 5 rotates due to the power transmitted from the main propulsion engine 2. The thrust generated by the rotation of the propeller pushes the propeller shaft to the left in the diagram (Figure 1), and this thrust is measured by the thrust measuring device 3. The rudder 6 is configured to be operable by the steering gear 7.

[0022] The ship's monitoring system includes a processing unit 20, which comprises a receiving unit 200 that receives the thrust output signal acquired by the thrust measuring device 3, an operation database 21 that stores the received thrust, an analysis unit 201 that analyzes the thrust stored in the operation database 21, and a processing unit 202 that corrects the propeller thrust based on the analysis results of the analysis unit 201.

[0023] Furthermore, the processing unit 20 estimates the hull's drag coefficient and propeller efficiency from the corrected thrust value of the ship's propeller 5.

[0024] The receiving unit 200 can receive various data from the propulsion main engine 2, thrust measuring device 3, steering gear 7, communication device 8, and information acquisition unit 9. The various types of data to be received include, for example, wind speed, wind direction, wave height, wave direction, ocean current speed and direction, tidal current speed and direction, water depth, water temperature, ship speed and direction relative to land, ship speed relative to water, bow heading, hull motion due to pitching and rolling, yawing, rudder angle, shaft rotation speed, propulsion engine fuel consumption rate, propulsion engine torque, draft depth, and trim. After receiving all of the listed data, it is possible to use only the data necessary for monitoring the ship, or to receive only the data necessary for monitoring the ship. The communication device 8 receives various weather data from the outside via the antenna 10. Weather data is also data that may affect the ship's energy efficiency, and examples include weather data such as wind speed, wind direction, wave height, and wave propagation direction.

[0025] Furthermore, the processing device 20 can acquire the thrust value (referred to as thrust value or simply thrust) generated by the propeller 5 of the ship's hull 1 using a thrust measuring device 3 consisting of measuring instruments. The thrust measuring device 3 can also estimate and output thrust from the amount of deformation of a thrust bearing installed on the hull to support the shaft directly coupled to the propeller against the thrust, which is preferable. Examples of thrust bearings installed on the hull include the bearing pads of thrust bearings. However, it is preferable to be able to detect the amount of deformation based on parts of the hull's propulsion engine's base plate bearing seat or other structures where strain and displacement can be detected, as shown in the figure.

[0026] The processing unit 20 receives data on shaft rotation speed, supercharger rotation speed, scavenging pressure, and fuel consumption rate from the propulsion main engine 2 at the receiving unit 200, and receives thrust values ​​from the thrust measuring device 3. Similarly, it receives data on the direction of the rudder 6 from the steering gear 7. The torque generated by the propulsion system is an estimated value using one or more of the following factors of the low-speed diesel engine: turbocharger rotational speed, scavenging pressure, fuel input and heat generation, and changes in cylinder pressure. The output Ee of the propulsion system is calculated by multiplying the torque generated by the propulsion system by the output shaft rotational speed of the low-speed diesel engine. It is preferable that the information acquisition unit 9 receives the aforementioned data and the communication device 8 receives weather data, and saves them in the operation database 21 along with the time. The data received from the communication device 8 and the information acquisition unit 9 may be configured to receive all of the listed data and then use only the data necessary for monitoring the vessel, or it may be possible to receive only the data necessary for monitoring the vessel.

[0027] If a shaft horsepower meter (not shown) is installed, the shaft output may be stored in the operation database 21. This allows for obtaining data to determine the propeller efficiency, as described later.

[0028] If a shaft horsepower meter is not installed, the shaft output may be predicted from the shaft rotation speed of the propulsion main engine 2, the turbocharger rotation speed, the scavenging pressure, and the fuel consumption rate. For prediction, the characteristics of the propulsion main engine 2 can also be stored in the operation database 21 and used.

[0029] The thrust measurement device 3 receives the thrust value, analyzes the stored thrust value, and corrects it. The processing device 20 performs the entire process from acquiring the measured thrust value to correcting it.

[0030] The part where the deformation is detected may be the thrust bearing of the main propulsion engine 2, or the thrust girder, and it is preferable to detect at multiple locations, and even more preferable to use these in combination. In addition, bending of the bearing pad (not shown) may be detected. Furthermore, strain and / or displacement of the thrust bearing collar of the crankshaft may be detected.

[0031] The processing unit 20 performs the following correction on the output of the deformation amount detected by the thrust measuring device 3. For temperature-related changes, it is preferable to create a correction table through calculations and experiments. This correction table does not need to be created for each vessel; it is preferable to have one prepared for each thrust bearing installed on the vessel. The effects of vibrations caused by combustion are reduced using a low-pass filter. The time constant of the low-pass filter is preferably, for example, around 2 to 5 seconds. The effects of wave-induced changes in rotational speed can be reduced using a low-pass filter or avoided by applying a moving average. The time constant of the low-pass filter is, for example, around 5 to 20 seconds. In this way, by analyzing the effects of combustion, temperature, waves, etc. caused by the deformation using a correction table and a low-pass filter, the thrust value can be corrected and determined based on the deformation.

[0032] (The hull's drag coefficient and propeller efficiency are calculated based on the corrected thrust values.) The processing unit 20 calculates the hull's drag coefficient and propeller efficiency from the corrected thrust value of the ship's propeller 5. The following describes a method for calculating the hull's drag coefficient and propeller efficiency based on the corrected thrust value.

[0033] In the absence of significant acceleration or deceleration, the hull resistance (resistance force) Fr is approximately equal to the thrust Fp (Fp = Fr), and the hull resistance Fr is proportional to the product of the square of the ship speed Vg and the hull resistance coefficient Kd.

[0034] When the above relationship is expressed as an equation, the propeller efficiency Ep can be given by the thrust Fp, the shaft output Ee of the propulsion engine, and the ship's speed over ground Vg as follows (Equation 1-1). (Equation 1-1) Propeller efficiency Ep = Vg × Fp / Ee

[0035] Based on the above (Equation 1-1), the propeller efficiency can be calculated from the corrected thrust values ​​obtained from the thrust measuring device 3 and the processing device 20, the shaft output obtained from the processing device 20, and the ship speed over ground obtained from the information acquisition unit 9.

[0036] Furthermore, given the thrust Fp, hull resistance (resistance force) Fr, and ground speed Vg, if the ship is moving at a constant speed, Fp = Fr holds true, and the hull resistance coefficient Kd can be expressed as shown below (Equation 2-1). (Equation 2-1) Resistivity coefficient Kd = Fp / (Vg) 2

[0037] Based on (2-1) above, the drag coefficient can be determined from the corrected thrust value obtained by the thrust measuring device 3 and processing device 20, and the ship speed over the ground obtained from the information acquisition unit 9.

[0038] Equations (1-1) and (2-1) above essentially describe the phenomenon well and are relationships that are well known to those skilled in the art.

[0039] The processing unit 20 can calculate the drag coefficient and propeller efficiency by acquiring the current draft depth obtained by the information acquisition unit 9, the thrust corrected by the thrust measuring device 3 and the processing unit 20, the torque obtained from the main propulsion engine 2, the shaft rotation speed, and the ship's speed.

[0040] Equations (1-1) and (2-1) above are relational equations for when the ship is operating in still water or when the ship is not undergoing significant acceleration or deceleration. Therefore, they do not necessarily coincide with actual operations that involve external disturbances such as ocean conditions, imperfections in sensor measurements, or fouling during operation, which can lead to changes in the ship's energy efficiency.

[0041] Therefore, by identifying the causes of deterioration and eliminating them as appropriate, it becomes possible to provide accurate energy efficiency data for ship operations, propose maintenance and operational strategies based on this information, and conduct a fair evaluation of the ship.

[0042] A preferred embodiment of the processing flow of the monitoring system of the present invention is described below. Figure 2 shows an example of the processing flow of the ship monitoring system of the present invention.

[0043] As shown in Figure 2, the processing unit 20 first acquires deformation amounts from strain sensors installed in the thrust measuring device 3, and also acquires various data from the main propulsion engine 2, propulsion shaft 4, steering gear 7, communication device 8, and information acquisition unit 9 installed on the ship (S1). Here, if the thrust measuring device 3 has multiple strain sensors installed, it can acquire deformation amounts from each strain sensor and output the optimized deformation amount to the processing unit. The various data acquired by the processing unit 20 are stored in the operation database 21.

[0044] The various data serve as the basis for calculating factors that may lead to changes in the energy efficiency of ships, and are the basis for primary and unavoidable factors.

[0045] (Primary factors) Increase in drag coefficient: The adhesion of organisms to the hull reduces its smoothness, leading to an increase in viscous resistance and thus an increase in the drag coefficient. Therefore, it is preferable to collect data on the adhesion of organisms to the hull and store it in the operational database 21. Reduced propeller efficiency: Biofouling and erosion of the propeller affect the reduction in propeller efficiency. Therefore, it is preferable to collect data on biofouling and erosion of the propeller and store it in the flight database 21.

[0046] Other examples include the following data. ·Heading • Steering angle Draft depth • Trim (whether it's bow trim or stern trim) and trim angle

[0047] (Inevitable factors) Inevitable factors affecting the reduction in hull efficiency include, for example, the following data, and it is preferable to collect some or all of this data and store it in the operational database 21.

[0048] • Weather data • Oceanographic data • Ocean current data • Tidal current data • Ship motion due to pitching, rolling, and yawing • Unavoidable diagonal movement due to wind and waves (deviation in the direction of the bow)

[0049] Based on this data, it is preferable to estimate the degree of influence of each factor. More details will follow later.

[0050] Next, based on the acquired data, the current thrust is calculated, the calculated thrust is corrected, and the drag coefficient and propeller efficiency are calculated based on the corrected thrust (S2). In the illustrated example, the flow shows the output of the deformation amount by the thrust measuring device 3, but if the thrust measuring device 3 had calculated the thrust based on the deformation amount, it would not be necessary to calculate the current thrust, and only the calculated thrust would need to be corrected. Furthermore, if the thrust measurement device 3 also performs thrust correction, the processing device 20 may not perform the calculation to correct the calculated thrust. Instead, the processing device 20 may perform the calculation of the thrust corrected by the thrust measurement device 3, obtain the corrected thrust, and then calculate the drag coefficient and propeller efficiency based on the corrected thrust.

[0051] (Resistance coefficient model) To calculate the drag coefficient, it is preferable to create a drag coefficient model by using the above equation (2-1) with the draft depth as a condition, and modeling the relationship between thrust and ship speed. That is, it is preferable to make the relationship between thrust Fp and ship speed Vg a function.

[0052] The relationship between thrust Fp and ship speed Vg is expressed by substituting the hull resistance coefficient into the above relational equation (Equation 2-1). It is preferable to store the resistance coefficient model in a memory unit (not shown) of the processing unit 20 and use it when calculating the resistance coefficient.

[0053] (Propeller efficiency model) Similar to the drag coefficient model, it is preferable to create a propeller efficiency model that calculates the propeller efficiency Ep from the output Ee and thrust Fp of the main propulsion engine using the above (Equation 1-1). It is also preferable to store the propeller efficiency model in a memory unit (not shown) of the processing unit 20, similar to the drag coefficient model, and use it when calculating the propeller efficiency.

[0054] By acquiring various data such as thrust values, ship speed, and propulsion engine output collected under initial conditions from sea trials and post-maintenance tests in dry dock, the initial drag coefficient and initial propeller efficiency can be derived from the drag coefficient model and the initial propeller efficiency model. These derived initial drag coefficient and initial propeller efficiency represent the drag coefficient and propeller efficiency under idealized conditions where the effects of ship operation can be ignored. Furthermore, it is preferable to store various data for determining the drag coefficient and propeller efficiency in the operational database 21 as initial data. Furthermore, the drag coefficient model and propeller efficiency model can utilize data from normal voyages, collect information on changes in draft depth, and calculate the current propeller efficiency and drag coefficient during normal sailing. This allows for the continuous calculation of the drag coefficient and propeller efficiency under current operating conditions, enabling monitoring of the ship's condition. Furthermore, by using past operational data, it is possible to understand the deterioration trends and changes in propeller efficiency and drag coefficient in past operational performance. This makes it possible to predict the condition of the hull by comparing and analyzing the current state of the hull with past operational performance. Instead of creating the above model, it is also acceptable to estimate and utilize the model through computer simulation using methods well-known to shipbuilding engineers.

[0055] As described above, the drag coefficient and propeller efficiency can be calculated using mathematical methods involving information processing and multivariable functions.

[0056] Next, the drag coefficient calculated based on the current thrust is determined, and the difference from the initial value is calculated (S3). Using the drag coefficient model described above, it is possible to understand how much the current propeller efficiency has changed from the initial propeller efficiency. Furthermore, understanding the degree of change is also preferable in identifying the factors that caused the change. In other words, since the drag coefficient and propeller efficiency of the current operating state can be continuously calculated, the difference between the initial stage and the state during navigation (operating state) can be continuously calculated based on the initial drag coefficient and initial propeller efficiency. This difference is a factor that affects the changes in the drag coefficient and propeller efficiency during navigation. By identifying this factor or acquiring various data to predict it, it is possible to monitor the ship and appropriately understand its capabilities.

[0057] Initial ship data, including draft depth, thrust Fp, and ship speed Vg, is pre-stored in the operational database 21. By applying this data to the drag coefficient model and propeller efficiency model described above, the initial drag coefficient and propeller efficiency can be estimated as initial values ​​in still water. Initial data should preferably be obtained at the time of completion or when performing modifications in dry dock, to calculate the propeller efficiency and drag coefficient in still water using the above-mentioned (Equations 1-1) and (Equations 2-1). This data should be obtained under conditions where the draft depth and trim are kept constant, and the output of the main propulsion engine (torque and shaft rotation speed) and ground speed should be obtained. It is also preferable to obtain data for bow trim, even keel, and stern trim. Furthermore, it is preferable to obtain data in advance for two different draft depths, for example, with a full load and with no load.

[0058] As mentioned earlier, equations (1-1) and (2-1) do not always coincide in actual operation. This is due to external disturbances such as sea conditions, imperfections in sensor measurements, and fouling during operation. In particular, the drag coefficient Kd has different contributing factors than resistance represented by viscous resistance (which is largely determined by the draft depth and shape of the ship) and wave resistance (losses due to the hull displacing water). This is because it becomes more complex in actual sea conditions (not in calm water) due to the effects of hull movement and wind waves.

[0059] Propeller efficiency Ep is affected by the propeller's submersion depth and pitching, but it is often defined by the deviation from the optimal design point (expressed as a pair of ship speed and rotational speed, which is roughly proportional in a graph with ship speed on the horizontal axis and rotational speed on the vertical axis), making changes in efficiency relatively easy to estimate.

[0060] By utilizing the above relationship, it is possible to continuously collect data, estimate the proportionality coefficient, and thereby determine the hull resistance coefficient and propeller efficiency from the thrust, propulsion engine output, and ship speed.

[0061] Next, after calculating the difference, a factor estimation model is used to separate and estimate the primary and unavoidable factors (S4).

[0062] Hull resistance changes due to unavoidable causes such as wind (headwind and tailwind), waves, ocean currents, and tidal currents, as well as fouling caused by marine organism attachment and maintenance / operational factors related to maneuvering. The current drag coefficient and the initial drag coefficient are continuously compared and recorded in the operational database 21 along with data such as wind, waves, and operational conditions at that time. By processing and analyzing the recorded data and the drag coefficient using AI technologies such as multivariate analysis and machine learning, a factor estimation model is created that estimates the influence of various factors on the drag coefficient. Similarly, the influence of various factors on propeller efficiency is estimated.

[0063] In the case of ships, sea conditions are highly likely to be a factor that degrades propeller efficiency and drag coefficient, and are an unavoidable factor for shipowners. Therefore, in this invention, it is preferable that the processing device 20 quantifies the sea conditions estimated from data selected from wind speed, wind direction, and wave conditions. In this embodiment, sea conditions affect the propeller efficiency and drag coefficient of a ship, so estimating and quantifying their fluctuations is of great significance.

[0064] Each oceanographic element, such as wind speed, wind direction, and wave conditions, may be quantified individually, or they may be combined to quantify the degree of influence of oceanographic conditions.

[0065] For example, if the value of a target item such as wind speed has a negligible impact on fuel efficiency, it is set to a standard score of 0. Points are then assigned to each item according to the magnitude of its impact, and the degree of impact can be quantified by the total score of the sea conditions. The propeller efficiency and drag coefficient can be corrected according to the score. This makes it possible to calculate the propeller efficiency and drag coefficient of the hull excluding the effects of sea conditions. In this case, it is preferable to determine the proportion that can be excluded based on the total score of the oceanographic factors, which are unavoidable.

[0066] When estimating the factors that degrade the drag coefficient and propeller efficiency, it is preferable to separate and extract primary factors in addition to unavoidable factors. For example, data can be extracted when factors are changing, even when sea conditions are not a factor. This allows for the isolation of factors that degrade propeller efficiency and drag coefficient, which can then be used to make decisions regarding cleaning the hull or repairing the propeller.

[0067] For example, temporary factors include factors related to draft depth, trim, and fouling. Regarding draft, it is preferable to estimate its influence using calculations and experimental results from the design and manufacturing processes. Regarding trim, it is preferable to determine it during sea trials immediately after completion or after dock maintenance. Regarding fouling, it is preferable to estimate the level of fouling on the hull and propeller based on the time elapsed since the last cleaning. Furthermore, the amount of fouling may be calculated as follows, based on the water temperature and residence time in the area of ​​the voyage. Degree of contamination X = Kt0 × T0 + Kt1 × T1 + Kt2 × T2 + ... Here, Kt is a function of water temperature representing the degree of fouling, T is the residence time, and the fouling can be accumulated by dividing the voyage into segments from 0 to n.

[0068] Furthermore, temporary factors may be separated and extracted into factors caused by steering and factors caused by fouling. Hull resistance varies due to unavoidable factors such as wind (headwind and tailwind), waves, ocean currents, and tides, as well as maintenance-related factors such as fouling caused by the attachment of marine organisms, and operational factors such as frequent oblique turns due to maneuvering. Therefore, by continuously comparing the current drag coefficient with the initial drag coefficient and recording this data, along with wind, wave, and operational data, in the operational database 21, and then processing and analyzing the recorded data and drag coefficient using a factor estimation model trained through multivariate analysis or machine learning, it is possible to estimate the influence of various factors on the drag coefficient. Similarly, the influence of various factors on propeller efficiency can be estimated. Draft depth, waves, and hull motion can be recorded and processed as factors.

[0069] In this embodiment, the processing device 20 may process the decrease in the drag coefficient and propeller efficiency related to fouling and wear in a way that can be converted into fuel consumption over a certain period and displayed. Furthermore, it is possible to estimate ship speed and engine operating frequency based on past operational data, and then make estimates based on those assumed operating frequencies. Furthermore, by separating factors causing contamination and wear from factors caused by operation, and showing only the changes due to contamination and wear, the effectiveness of maintenance can be appropriately demonstrated. Furthermore, factors related to operation can be used to score the methods of ship handling or the skill level of the personnel in charge, which can then be used as a reference for more efficient operation.

[0070] Next, eliminate the unavoidable factors (S5). The factor estimation model models the impact of each factor, allowing us to identify the effects of unavoidable factors such as ocean conditions from current data and then estimate performance and efficiency by working backward to eliminate unavoidable performance changes.

[0071] Here, (A) the performance changes separated for each factor may be subtracted. This allows us to estimate the degree of change due to each factor, which can contribute to improvement suggestions.

[0072] Alternatively, using a method similar to that used for constructing the factor estimation model (B), unavoidable factors can be grouped together and solved as an optimal problem, or they can be estimated separately from the beginning.

[0073] If there were no mutual influence between the various influencing factors (i.e., their influences were independent), then we could simply subtract the separate degree of change for each factor mentioned above. However, in reality, there is mutual influence, but the degree of influence can vary from case to case. For example, rough seas increase the ship's movement, amplifying the effect of steering. Therefore, in that case, (B) may provide a better estimate, but generally (B) is more complex and technically more advanced than (A). It is also useful to use (A) for factors with less influence (e.g., water depth and water temperature) and (B) for others.

[0074] Next, the operating time and energy consumption are corrected and displayed (S6). Specifically, based on performance excluding unavoidable factors, operating time and GHG emissions or energy consumption are adjusted to estimate and display the total GHG emissions and energy consumption for the entire voyage. Preferably, the display uses a display device (not shown) that allows the user to perceive the ship's performance during navigation. This allows for the separation of environmental performance changes caused by unavoidable factors, thus providing a basis for fair incentives.

[0075] The vessel according to the present invention may be any vessel used for shipping, but a preferred example is a vessel in which a propeller is directly connected to a low-speed diesel engine, which is the propulsion engine, via a rotating shaft.

[0076] In this invention, the fuel for the ship's propulsion engine is not limited to heavy oil, but may also be LPG (liquefied natural gas), ammonia, hydrogen, or any mixture thereof. Furthermore, the propulsion engine may be an electric motor.

[0077] A preferred example of a part for detecting the amount of deformation is explained with reference to Figure 3. Figure 3 is a perspective view showing an example of a strain sensor mounting location on a ship's crankcase.

[0078] Figure 3 shows the crankcase 23, which is provided with multiple crank bearing cases 24, and the crankshaft is housed in the crank bearing cases 24. A thrust bearing case 25 is provided on the stern side of the crankcase 23, and the thrust bearing is housed in the thrust bearing case 25. Inside the thrust bearing case 25, there is a reinforcing plate 26 to reinforce the thrust bearing case 25. In the illustrated example, the reinforcing plate 26 is provided near the center in the vertical direction of the thrust bearing case 25, but it is not limited to this and may be provided inside the thrust bearing case 25. In this embodiment, it is also preferable that the part where the amount of deformation is detected is the reinforcing plate 26, and it is preferable to provide a strain sensor on the reinforcing plate 26. When the crankshaft is pushed in the thrust direction within the crankcase 23 by thrust, the crankcase 23 deforms, and the reinforcing plate 26 is easily affected by the deformation of the crankcase 23. By providing a strain sensor on the reinforcing plate 26, the amount of deformation of the crankcase 23 can be detected more accurately.

[0079] Furthermore, it is preferable to install strain sensors at the lower part of both sides of the crankcase 23 and at the strain sensor mounting position 27 near the outside of the thrust bearing case 25. Installing strain sensors at the strain sensor mounting position 27 is preferable because it provides good access for installation and is not affected by lubricating oil. It is also preferable from the standpoint of easy installation (retrofit) to existing ship engines and easy maintenance. In this embodiment, it is preferable to install strain sensors at a location that is easily accessible for installation and is not affected by lubricating oil, rather than being limited to the strain sensor mounting position 27 shown in the figure.

[0080] Furthermore, it is preferable to install strain sensors near the bolt fastening portion 28 that fastens the ship's propulsion engine mounting base to the crankcase 23. The bolt fastening portion 28 is installed by being inserted without any gaps through a reamed hole that penetrates the lower part of the crankcase 23 and the upper plate of the engine mounting base. For this reason, the vicinity of the bolt fastening portion 28 is also a preferred location for detecting strain using strain sensors.

[0081] In the embodiment described above, the processing unit 20 is described as correcting the output of the deformation amount detected by the thrust measuring device 3 as follows, but it is not limited to this, and the thrust measuring device 3 may be a strain sensor. The deformation amount detected by the strain sensor may be output to the processing unit 20 to calculate the thrust value. Alternatively, the thrust measuring device 3 may calculate the thrust value based on the deformation amount detected by the strain sensor, correct the calculated thrust value, and then output the corrected thrust value to the processing unit 20.

[0082] Figure 4 is an explanatory diagram showing another embodiment of the device configuration of the ship monitoring system of the present invention. In Figure 4, the same reference numerals as in Figure 1 are described in the same way as in Figure 1, and therefore their description is omitted.

[0083] Figure 4 shows a configuration in which data is transmitted and received with a ship via a land-based antenna 11, and calculations are performed at a land-based terminal 12.

[0084] In a vessel, as shown in the embodiment, thrust, drag coefficient, and propeller efficiency are calculated on board. However, these calculation results may be transmitted to a land-based antenna 11 via the vessel's antenna 10, and the calculation results may be stored at a land-based terminal 12. The land-based terminal 12 may be connected to a database (not shown) and the calculation results may be stored in the database. This allows for the backup of valuable navigation data, which can then be used as reference data for other vessels via the land-based terminal 12. Alternatively, instead of calculating the results on board the ship, the data obtained on board the ship may be sent to the land terminal 12, where the thrust, drag coefficient, and propeller coefficient are calculated. The calculated results may then be sent back to the ship via the land antenna 11 to the ship's antenna 10, and stored in the operation database 21 via the processing unit 20.

[0085] Furthermore, the land-based terminal 12 can perform only the calculation of the drag coefficient and propeller efficiency, while the ship can calculate and correct the thrust value and send the obtained thrust value along with the data obtained on board to the land-based terminal 12. In this way, the computational load on the processing unit 20 can be reduced.

[0086] The embodiments described above are merely examples and are not intended to limit the scope of the invention. The invention can be implemented in various other forms, and various omissions, substitutions, and modifications are permitted without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents. [Explanation of symbols]

[0087] 1: Hull 2: Main propulsion engine 3: Thrust measurement device 4: Propulsion shaft 5: Propeller 6: Rudder 7: Steering gear 8: Communication device 9: Information acquisition section 10: Antenna 20: Processing unit 200: Receiver 201:Analysis Department 202: Processing Unit 21: Flight Database

Claims

1. Equipped with a processing unit that receives, stores, and analyzes output signals from ships, The aforementioned processing device calculates the propeller efficiency and drag coefficient in the initial stage and during navigation based on the collected thrust values, ship speed, or propulsion engine output. The difference between the initial stage and the navigation period is calculated for the propeller efficiency and the drag coefficient. A ship monitoring system characterized by quantifying, recording, and analyzing the temporary and unavoidable factors from the aforementioned difference, and identifying or predicting the factors that affect the changes in the drag coefficient and propeller efficiency.

2. The aforementioned vessel is further equipped with a thrust measuring device, The ship monitoring system according to claim 1, characterized in that the thrust value is received from the thrust measuring device.

3. The ship monitoring system according to claim 1, characterized in that the propeller efficiency and drag coefficient in the initial stage are selected from still water, when the ship is not accelerating or decelerating, from sea trials, or from tests after maintenance in a dock.

4. The ship monitoring system according to claim 1, further characterized by separating some of the factors that affect the propeller efficiency and the drag coefficient.

5. A ship monitoring system according to claim 4, characterized in that some of the factors causing the separation are the unavoidable factors, and the ship's fouling or propeller wear is extracted from the propeller efficiency and drag coefficient after the separation.

6. A ship characterized by being equipped with a ship monitoring system according to any one of claims 1 to 5.

Images