Method and system for diagnosing maintenance needs for marine vessels - Patents.com

Abstract

The present disclosure provides a method for optimizing ship maintenance, the method including obtaining ship operational data, calculating a torque index, calculating a slip index, indicating a propeller wash is required if the torque index exceeds a torque index threshold, and indicating a hull wash is required if the slip index exceeds a slip index threshold.

Description

[Technical field]

[0001]

[0001] The present invention relates to a method and system for diagnosing the need for maintenance on a sea-going vessel. The vessel may be a ship. The vessel may be a commercial vessel, for example for carrying bulk cargo. The cargo may include, but is not limited to, one or more of crude oil, petroleum products, LNG, hydrogen, ISO containers, granular materials, etc. [Background technology]

[0002]

[0002] Large ocean-going ships are usually subjected to repair activities, for example every 5 years, during which the underwater parts are painted and the propellers are polished. The performance of the ship deteriorates over the 5-year period. The rate and extent of deterioration depends on several factors, but one that has a decisive impact and can be influenced is the choice of paint applied. The shipping industry has developed a standard, ISO 19030, to quantify performance in terms of speed loss for a given power. However, this methodology does not take the final step required to monetize the impact of performance deterioration.

[0003] Underwater coatings applied to ships have a limited design life, e.g. 5 years. Proposals to increase this to 7.5 years are becoming widespread in the shipping industry. A ship whose underwater coating performance has deteriorated over time may require, e.g., up to 25% more power or 25% more fuel to achieve the same speed compared to a newly applied condition. As a result, the average fuel consumption across the fleet generally exceeds the "ideal" or best achievable value. Overall fuel consumption may steadily exceed the ideal value by about 9% for a large number of ships.

[0004] Fleet management generally tends to assume that the speed required by the voyage order is fixed, so the effect of performance degradation is to increase power demand, thereby increasing fuel consumption, costs, and emissions. Fuel consumption management can be done using the Hull Resistance Index (HRI), which is typically based on ISO standard 19030. The HRI takes the relationship between power and speed to determine the increase in power demand to maintain the required speed. This directly translates to increased fuel, costs, and emissions, but does not attribute this degradation to hull or propeller factors.

[0005] Cleaning a ship's hull is generally significantly more expensive than polishing the propeller alone. While propeller polishing can be performed relatively easily in shallow water, hull cleaning requires complex procedures and special equipment, especially for larger vessels with a certain draft, e.g., over 10 metres. ISO standards and HRIs cannot distinguish whether deterioration is the result of hull or propeller problems. To mitigate this, some operators perform propeller polishing on a regular basis. Other fleets, including the fleet managed by the applicant, perform propeller polishing on an ad-hoc basis.

[0006] There are technologies that aim to be able to determine the deterioration of a propeller, either by mathematical means or by fitting shaft thrust meters that supposedly measure the thrust generated accurately and thereby directly determine the efficiency of the propeller. However, the relatively high capital expenditure (CAPEX) for these thrust measurement systems, and the fact that they are highly novel products, have resulted in very slow adoption to date. In any event, it is unrealistic to expect large-scale thrust meter retrofit programs to be undertaken for existing tonnage, and as most vessels in the Applicant's portfolio are chartered on either a long-term or short-term basis, a data-driven approach is essential.

[0007] WO 2019 / 243932 discloses a method and device for detecting fouling of a propeller installed on a ship and connected to the main engine powering the propeller, the method comprising comparing the revolutions per unit time of the propeller versus time obtained during coastal navigation maneuvers in real conditions with a corresponding curve obtained during coastal navigation maneuvers with an unfouled propeller.

[0008] U.S. Pat. No. 10,543,886 discloses an exemplary method for a marine vessel having a propeller mounted on a rotatable shaft to convert rotational shaft power transmitted from the shaft to the propeller into thrust to propel the marine vessel through water, the method including obtaining measurements representative of shaft power, thrust and underwater speed of the marine vessel, separately estimating at least one of a first excess shaft power caused by fouling of the propeller and a second excess shaft power caused by fouling of a hull of the marine vessel, issuing a propeller washing instruction in response to the first excess shaft power and issuing a hull washing instruction in response to the second excess shaft power.

[0009] Notwithstanding the advantages and cost savings offered by the above-referenced systems, the present disclosure aims to provide alternative methods and systems that offer further improvements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 243932 [Patent Document 2] U.S. Pat. No. 1,054,3886 Summary of the Invention

[0004]

[0010] Among other things, the present disclosure provides methods for improving vessel maintenance, hull cleaning, and propeller cleaning, which may allow for a reduction in fuel consumption beyond a desired level, such as 9%. In addition to improved performance with proper maintenance resulting in less fuel consumption, the methods described herein allow for the need for hull cleaning or maintenance to be assessed separately and independently of propeller performance, which may indicate a need for propeller cleaning and maintenance. The methods disclosed herein provide vessel maintenance options to (a) perform both hull cleaning and propeller polishing, (b) perform hull cleaning only, or (c) propeller polishing alone. Knowing what type of maintenance is needed can reduce unnecessary costs that may be incurred by performing both hull cleaning and propeller polishing when only propeller polishing is required, especially when hull cleaning is typically significantly more costly than polishing the propeller alone.

[0011] Most cleaning methods tend to remove some of the paint film and leave micro-scratches on the cleaned surface, which act to accelerate fouling after cleaning. Repeated hull cleaning during a repair cycle can result in excessive removal of paint film thickness, making it impossible to maintain the surface in a high performance state except by early repair and repainting. The insight provided by the present invention ensures that hull cleaning is only performed when actually required by fouling, thereby eliminating premature paint wear.

[0012] In one aspect, the invention provides a computer-implemented method for diagnosing a need for maintenance on a sea-going vessel, the vessel comprising a hull, a propeller, an engine, and a drive shaft connecting the engine to the propeller, the method comprising: (a) calculating a propeller distance using formula (A), Propeller Distance = (nominal pitch) * (a number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A) The nominal pitch is a value indicating the pitch at a radius of 0.7. calculating an observed RPM, which is a value indicative of the number of revolutions per minute of the drive shaft over a selected period of time; (b) calculating a slip factor using equation (B), Slip coefficient = (propeller distance) / (observation distance)(B) Calculating the observed distance, where the observed distance is the observed distance traveled by the vessel over a selected period of time; (c) outputting at least one of a propeller sharpening indicator and a hull cleaning indicator, the propeller sharpening indicator being output as a separate value from the hull cleaning indicator.

[0013] The step of outputting the propeller grinding indicator includes: - calculating a reference torque multiplier using formula (C), Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) 3 (C) Rated engine power is the maximum power output of an engine specified by the engine manufacturer. Calculate the rated RPM, which is the maximum RPM of the propeller at the rated engine power specified by the engine manufacturer; - calculating an observed torque multiplier using formula (D); Observed Torque Multiplier = Observed Engine Power / (Observed RPM) 3 (D) - calculating the torque index using formula (E); Torque index = (number in the range 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip factor) 2 (E) - Comparing the torque index to an upper torque index threshold.

[0014] The step of outputting a hull cleaning indicator comprises: - calculating the slip index using formula (F); Slip index = (number in the range 85-110) * (slip coefficient) 3 (F) - Comparing the slip index to an upper slip index threshold.

[0015] Optionally, the step of outputting a propeller sharpening indication further comprises comparing the torque index to a lower torque index threshold and an upper torque index threshold, indicating that propeller sharpening would be beneficial if the torque index exceeds the lower torque index threshold but not the upper torque index threshold, and indicating that propeller sharpening is necessary if the torque index exceeds the upper torque index threshold. Optionally, the step of outputting a hull cleaning indication further comprises comparing the slip index to a lower slip index threshold and an upper slip index threshold, indicating that hull cleaning would be beneficial if the slip index exceeds the lower slip index threshold but not the upper slip index threshold, and indicating that hull cleaning is necessary if the slip index exceeds the upper slip index threshold.

[0016] Optionally, the method further comprises adjusting at least the upper slip index threshold, and optionally the lower slip index threshold, over a period beginning from when the marine vessel was last painted.

[0017] Optionally, the method further comprises resetting at least the upper slip index threshold, and optionally the lower slip index threshold, when the marine vessel is painted.

[0018] Optionally, the step of calculating the slip index comprises calculating a rolling average of the slip index over a period of time, optionally at least 15 days, more preferably 30 days.

[0019] Optionally, the step of calculating the torque index comprises calculating a rolling average of the torque index over a period of time, optionally at least 15 days, more preferably 30 days.

[0020] This improvement can be achieved without the need for additional hardware or sending data for expert interpretation. The process can be embedded into existing dashboards to get results, or can be performed in a simple stand-alone spreadsheet. Data sources can include simple noon reports or high frequency automated data. [Brief description of the drawings]

[0005]

[0021] The drawings depict, by way of example only, and not by way of limitation, one or more embodiments consistent with the present teachings.In the drawings, like reference numbers refer to the same or similar elements. [Figure 1] 1 illustrates a flow diagram of one embodiment of the present invention. [Diagram 2] FIG. 1 depicts a comparative diagram showing exemplary HRI data for a vessel over time since last repair (maintenance). [Diagram 3] FIG. 1 depicts a diagram showing exemplary slip index data (based on operational noon data) for a vessel over time since last repair. [Figure 4] FIG. 1 depicts a diagram showing an exemplary torque index (based on operational noon data) for a vessel over time since last repair. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006]

[0022] The method described herein advantageously allows for the differentiation of the effects of the propeller and the hull in the overall performance loss determined from the speed loss as described in ISO 19030 or a similar calculation. The method described herein allows for the propeller performance and the hull performance to be evaluated separately, which allows for the hull condition and the propeller condition to be evaluated separately and independently of each other. This allows for the tailoring of maintenance activities to actual needs.

[0023] The disclosed method and system can reduce the overall fuel consumption of a fleet by at least 1-2% overall. Herein, where a large number of vessels typically exceed the ideal average fuel consumption by about 9%, the disclosed method and system can reduce the excess fuel consumption on average across the fleet by about 2%, and in fact perhaps more. Furthermore, various embodiments of the present invention can be implemented via computer executable instructions, and various elements of embodiments of the present invention are essentially software code that defines the operation of such various elements. Also, embodiments of the present invention may be implemented in a controller or processor. The executable instructions or software code may be retrieved from a readable medium (e.g., hard drive medium, optical medium, EPROM, EEPROM, tape medium, cartridge medium, flash memory, ROM, memory stick, etc.) or communicated via a data signal from a communication medium (e.g., the Internet). In fact, the readable medium may include any medium capable of storing or transferring information.

[0024] As used herein below, the terms may be defined as follows:

[0025] The term "engine power" relates to the engine power (expressed for example in horsepower or kW) that is delivered to the drive shaft.

[0026] The term "HRI" means Hull Resistance Index, which has its ordinary meaning known to those skilled in the art. In general, this index uses ship performance data, sometimes called operational data (known to those skilled in the art as "midday data"), as input and compares the power and speed of each ship to a "hypothetical curve" that has a cubic curve based on reference speeds in loaded and ballast conditions related to engine power. Sister ships are given the same reference value so that the relative performance of different coatings and / or other in-dock treatments can be quantified. Composite numbers are generated for each coating cycle in an attempt to quantify the relative performance of different coatings over their life cycle, for example 2.5-year and 5-year cycles. A baseline value of 100 represents the expected performance of a new coating from a refit, and values ​​above it approximate the percentage of power increase required to compensate for the degradation in performance and achieve a given speed.

[0027] The term "lower slip index threshold" is a pre-defined value, determined by a user, indicating a level above which it would be beneficial to perform a hull wash. This value is preferably adjusted upwards over time to reflect possible deterioration of the hull due to increased fouling, etc. One skilled in the art may select this value based on historical data, for example, of when hull washing and / or painting would have been beneficial. For example, the methods described herein may be applied to past operational data to develop historical slip index values ​​that can be correlated to actual propeller conditions and need for polishing, from which an appropriate lower slip index threshold may be selected. In one example, the number of months since painting may be increased by 12. This value may be reset once the hull is washed and / or painted.

[0028] The term "lower torque index threshold" is a predetermined value determined by a user that indicates a level above which it would be beneficial to perform propeller sharpening. This value is preferably adjusted upward over time to reflect possible deterioration of the propeller due to increased fouling, etc. One skilled in the art can select this value based on historical data, etc., of when propeller sharpening would be beneficial. For example, the methods described herein can be applied to past operational data to develop historical torque index values ​​that can be correlated to actual propeller conditions and the need for sharpening, from which an appropriate lower torque index threshold can be selected. This value may be reset upon sharpening of the propeller.

[0029] The term "nautical mile" (Nm) has its ordinary meaning known to those skilled in the art and includes units of measurement used in maritime navigation and is intended for use in defining territorial waters. A nautical mile is defined as exactly 1,852 metres.

[0030] The term "nominal pitch" refers to the pitch at a radius of 0.7.

[0031] The term "observed distance" is the observed or actual distance traveled by a vessel in actual conditions over a selected period of time such as minutes, hours, days, etc., depending on the applicable operational data that is available. The applicable operational data typically includes underwater distance as indicated by a GPS tracker or (optionally) a logging system. The term actual distance may be used interchangeably with observed distance herein.

[0032] The term "observed engine power" is the observed or actual engine power of the vessel over a selected period of time, in particular a period already selected for operational data to which the methods described herein are applied. The selected period of time may be minutes, hours, days, etc., depending on the applicable operational data that is available. The applicable operational data typically includes distance underwater as indicated by a GPS track, or (optionally) a logging system.

[0033] The term "observed RPM" refers to a value indicative of the revolutions per minute of the drive shaft over a selected period, in particular a period already selected for operational data to which the method described herein is applied. The selected period may be minutes, hours, days, etc., depending on the applicable operational data that is available. The applicable operational data typically includes distance underwater as indicated by a GPS track, or (optionally) a logging system.

[0034] The term "observed torque multiplier" is calculated using formula (D).

[0007] Observed Torque Multiplier = Observed Engine Power / (Observed RPM) 3 (D)

[0035] Without being bound by theory, it has been found that there is a correlation between the observed torque multiplier value and the condition of the propeller, with increasing values ​​indicating increased fouling (i.e., worsening propeller condition).

[0036] The term "pitch at a radius of 0.7" has its ordinary meaning as known to those skilled in the art and may be referred to as the nominal pitch. Typically, each radius of a blade may have a different pitch. The pitch at a radius of 0.7 is often used as a representative value to indicate the nominal pitch when the propeller is in use (i.e., moving through the water). The pitch at a radius of 0.7 may be provided by the manufacturer.

[0037] The term "propeller" generally refers to an underwater device that has a rotating hub and radial blades set at a pitch that, when rotated, exerts a linear thrust to propel a vessel through the water. Most marine propellers are screw propellers with helical blades that rotate on a drive shaft.

[0038] The term "propeller distance" is calculated using the following formula (A):

[0008] Propeller Distance = (nominal pitch) * (a number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A)

[0039] The term "propeller pitch" has its ordinary meaning known to those skilled in the art, including the distance a propeller would theoretically advance in one revolution if the propeller was moving through a soft solid (i.e., there was no slip).

[0040] The term "propeller abrasion" refers to any type of cleaning method that can be applied to a propeller below the waterline. Typically, this includes, but is not limited to, physical abrasion.

[0041] The term "rated engine power" has its ordinary meaning including the maximum power output of the engine as specified by the engine manufacturer.

[0042] The term "rated RPM" has its ordinary meaning, including the maximum RPM of the propeller at rated engine power as specified by the engine manufacturer.

[0043] The term "reference torque multiplier" is calculated using formula (C).

[0009] Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) 3 (C)

[0044] The reference torque multiplier is not a commonly used measure in propeller calculations. Without being bound by theory, it has been found that an increase in this value indicates an increase in propeller torque due to an increase in propeller surface roughness. The reference torque multiplier is derived using reference information. The reference torque multiplier is different from the term "propeller torque coefficient kQ," which has a specific design value that does not change and therefore does not indicate any change to the propeller torque.

[0045] The term "RPM" has its ordinary meaning and relates to the rotational speed expressed in revolutions or revolutions per minute, which is usually associated with the rotation of shafts and propellers.

[0046] The term "shaft" refers to a drive shaft (alternatively called a propeller shaft) or similar mechanical connection between the engine and the propeller.

[0047] The term "slip coefficient" is calculated using formula (B).

[0010] Slip coefficient = (propeller distance) / (observation distance)(B)

[0048] Slip coefficient is a relative measure of propeller slip in water.

[0049] The term "slip index" (sometimes called "propeller slip index") is calculated using formula (F).

[0011] Slip index = (number in the range 85-110) * (slip coefficient) 3 (F)

[0050] The term "torque" refers to the torque (expressed, for example, in Nm) delivered by the engine to the shaft.

[0051] The term "torque index" (sometimes referred to as "engine / drive shaft / propeller torque index") is calculated using equation (E):

[0012] Torque index = (number in the range 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip factor) 2 (E)

[0052] The term "upper slip index threshold" is a predefined value determined by a user that indicates the level above which a hull cleaning should be performed. This value is preferably adjusted upwards over time to reflect possible deterioration of the hull due to increased fouling, etc. One skilled in the art may select this value based on historical data, for example, of when a hull cleaning and / or painting was beneficial. For example, the methods described herein may be applied to past operational data to develop historical slip index values ​​that can be correlated to actual propeller conditions and need for polishing, from which an appropriate upper slip index threshold may be selected. In one example, the number of months since painting may be increased by 12. This value may be reset upon cleaning and / or painting of the hull.

[0053] The term "upper torque index threshold" is a predetermined value, determined by a user, indicative of a level above which propeller sharpening is required. This value is preferably adjusted upward over an elapsed period of time to reflect possible deterioration of the propeller due to increased fouling, etc. One skilled in the art may select this value based on historical data, etc., of when propeller sharpening would be beneficial. For example, the methods described herein may be applied to past operational data to develop historical torque index values ​​that can be correlated to actual propeller conditions and need for sharpening, from which an appropriate upper torque index threshold may be selected. This value may be reset upon sharpening of the propeller.

[0054] The conversion of shaft power to speed in a ship involves two steps.

[0013] -Converts torque and RPM to produce thrust, -Use thrust to gain speed.

[0055] The first step is mainly determined by the propeller performance, and the second step is mainly determined by the hull performance. However, inevitably, the impact of the propeller on the hull performance is small, and the impact of the hull on the propeller performance is large.

[0056] In general, propeller slip is the difference between the actual distance the propeller travels forward through the water (prop distance) and the distance the propeller should theoretically travel without slip (prop pitch). For example, a propeller with a 21 inch pitch will theoretically travel 21 inches forward in one revolution through a soft solid (such as a screw turning through a piece of wood). However, when moving through the water, there will be some slippage and the propeller will travel less than theoretical. As mentioned above, propeller polishing (which may include painting or repainting) can help reduce slippage due to the deteriorated condition of the propeller (and thus improve performance leading to reduced fuel consumption). However, performing propeller polishing early, before such polishing is needed or required, will not reduce slippage, will incur increased costs, and will provide only minimal performance improvements and fuel savings. As mentioned above, this is also true for hull washing. Additionally, due to the cost differences associated with each of the hull cleaning and propeller polishing services, it is beneficial to know when each service is requested or needed, rather than simply performing both together.

[0057] The methods described herein enable the determination of whether hull cleaning is required or needed and / or whether propeller sharpening is required or needed, thereby allowing the benefits disclosed herein to be fully realized. Furthermore, the methods described herein can reliably determine a hull cleaning indicator or a propeller sharpening indicator based on (i) operational data including an observed distance traveled over a selected time period (Obsessed Distance), an observed engine power during a selected time period (Obsessed Engine Power), and an observed revolutions per minute (Obsessed RPM) during a selected time period, and (ii) vessel baseline information including a Propeller Pitch@0.7R value of the vessel's propeller (Propeller Pitch@0.7R), a Rated Engine Power value of the vessel's engine (Rated Engine Power), and a Rated Revolutions Per Minute value of the vessel's propeller (Rated RMP). Both such operational data and baseline information are readily available without the need for complex data acquisition, storage, and / or analysis sets (which may require additional equipment and / or third party involvement) or additional equipment (such as sensors) to derive hull and propeller status.

[0058] 1 shows step 100 of outputting indicators for hull cleaning and / or propeller sharpening, where each indicator output can be determined independently of each other. As shown in FIG 1, step 102 includes calculating the propeller distance using formula (A).

[0014] Propeller Distance = (nominal pitch) * (a number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A)

[0059] Observed RPM is a value indicative of the number of revolutions per minute of the drive shaft over a selected period, such as 24 hours if noon data is used, or over a shorter or longer period depending on the particular operational data.

[0060] Step 104 involves calculating the slip factor using equation (B).

[0015] Slip coefficient = (propeller distance) / (observation distance)(B) Observed distance is the observed distance traveled by the vessel over the same selected period as used in formula (A).

[0061] Step 106 involves outputting at least one of a propeller sharpening index and a hull cleaning index. As can be seen, the propeller sharpening index can be calculated and output separately from the hull cleaning index. Thus, a user can choose to output only the propeller sharpening index, or only the hull cleaning index, or both. Furthermore, these values ​​are provided separately by the methods and systems described herein to allow a user to know whether only the hull needs cleaning, only the propeller needs sharpening, or both. For example, the propeller sharpening index may be below an upper slip index threshold, while the hull cleaning index is above an upper torque index threshold. Such an output would inform the user that only the hull should be cleaned, thereby saving costs associated with possibly unnecessary propeller sharpening.

[0062] 1, step 106A of outputting a propeller sharpening indicator includes steps 202 through 208. Step 202 includes calculating a reference torque multiplier using equation (C).

[0016] Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) 3 (C)

[0063] Step 204 involves calculating the observed torque multiplier using equation (D).

[0017] Observed Torque Multiplier = Observed Engine Power / (Observed RPM) 3 (D)

[0064] Step 206 involves calculating the torque index using equation (E).

[0018] Torque index = (number in the range 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip factor) 2 (E)

[0065] Step 208 involves comparing the torque index to an upper torque index threshold.

[0066] 1, the step 106B of outputting the hull cleaning index includes steps 302 to 304. Step 302 includes calculating a slip index using formula (F).

[0019] Slip index = (number in the range 85-110) * (slip coefficient) 3 (F)

[0067] Step 304 involves comparing the slip index to an upper slip index threshold.

[0068] The step of calculating the slip index may advantageously comprise calculating a rolling average of the slip index. Calculating such a rolling average of the slip index may include: - averaging slip index values ​​over a period starting from the last repair (maintenance) of the vessel (typically the last 60 days) and resetting the rolling period when a maintenance operation occurs.

[0069] Grading the average slip index for a period of time includes:

[0020] - green, below the lower slip index threshold; - amber, above the lower slip index threshold but below the upper slip index threshold; - Red, above the upper slip index threshold.

[0070] The step of calculating the torque index may advantageously include the step of calculating a rolling average of the torque index. Calculating such a rolling average of the torque index may include: - averaging the torque index values ​​over a period of time (typically the last 60 days), starting from the last repair (maintenance) of the vessel, and resetting the rolling period when maintenance work occurs.

[0071] The average torque index ratings over a period of time include:

[0021] - Green, below the low torque index threshold; - amber, above the lower torque index threshold but below the upper torque index threshold; - Red, above upper torque index threshold.

[0072] The output can then be used for two purposes.

[0022] 1. In the short term, hull cleaning or propeller polishing can be targeted where it will bring the greatest benefit to a particular vessel.

[0023] 2. In the long term, coating selection and propeller polishing strategies can be developed based on actual data.

[0073] Either way, reduced fuel consumption can be achieved for any given vessel, thereby reducing both costs and emissions.

[0074] One advantage of the disclosed methods and systems is that the methods can be applied to a wide range of types of operational or performance data, especially data having different collection points. Exemplary types of operational or performance data include midday data collected once a day (daily), and data collected more frequently, such as once an hour (hourly), every 15 minutes, and / or real-time data. For example, if the methods and systems described herein are applied to midday data, the time period selected to calculate or apply observations would be 24 hours. If the type of operational data input is collected hourly, the time period selected may be 1 hour. It should be understood that one skilled in the art can select an appropriate time period, preferably a time period during which engine power and RPM remain relatively constant.

[0075] Once either the slip index and / or torque index enter amber (i.e. exceed their respective lower thresholds), operators are encouraged to consider mitigation opportunities. Once they enter red (i.e. exceed their respective upper thresholds), operators are encouraged to proactively seek mitigation opportunities.

[0076] For analysis according to the present disclosure, a rolling average of one or more performance indicators over a selected period is generated and plotted alongside a performance graph. The period over which the data is averaged is typically on the order of 15 to 90 days, for example 60 days. Where a 60 day average is mentioned, other periods may provide equally good results. If the system uses real-time inputs from sensors on board the vessel, the period may be shortened. However, a period of at least two days is preferred to account for weather effects.

[0077] The rolling average is reset after events such as propeller sharpening or hull washing to prevent any improvements being masked by a large number of pre-operation readings.

[0078] As shown in Figures 2-4, the three metrics HRI, slip index, and torque index average are plotted over a period of 60 months from the last vessel repair (maintenance). The vertical axis represents each index, and the horizontal axis represents time. Each data point at the beginning of the time represents a rolling average over 60 days. The values ​​have not been filtered in any way, e.g., weather-corrected. Each graph also plots the respective lower threshold (dashed line) and upper threshold (dash-dotted line). The diamond and cross symbols on the horizontal axis represent markers of the present invention indicating the time and type of work. Work can include hull cleaning (cross), propeller polishing (diamond), or both (diamond with cross), as will be made clear below.

[0079] The Hull Resistance Index (HRI) plotted in Figure 2 is not required to implement the methods and systems of the present disclosure, but provides a useful basis for comparison. HRI is commonly used in the shipping industry to indicate hull resistance. The change in HRI value after an operation can be seen very clearly on the second, third, fourth, fifth, and sixth operation markers on the horizontal axis.

[0080] The crosses in Figure 3 indicate that a hull cleaning operation was applied. It can be seen that the first and second hull cleaning operations did not result in a significant improvement (reduction) in the slip index, arguably indicating money not well spent. In particular, the slip index did not exceed the lower slip index threshold. The third and fourth hull cleanings produced an improvement (albeit for a relatively short time) evidenced by a downward slip index "jump". As can be seen in Figure 3, in these latter cases the slip index had started to exceed the lower slip index threshold (indicated by the dashed line) prior to the hull cleaning operation, whereas in the first two cases this was not the case.

[0081] The diamond symbols in Figure 4 indicate that the propeller polishing operations were performed more frequently. It can be seen that the first, third, fourth, sixth, and seventh polishes resulted in a notable improvement in the torque index. The second polish was not effective in reducing the torque index, and in fact, the torque index value before polishing was still close to the lower torque index threshold. The improvement caused by polishing was lost over a period of 3 to 6 months after polishing.

[0082] The analytical tools developed have been tested on over 20 vessels.

[0083]

[0024] [Table 1]

[0025]

[0084] According to the method of the present disclosure, if only the torque index exceeds a certain threshold, propeller polishing is likely sufficient. If only the slip index increases, or if both torque and slip increase, hull cleaning is advisable. If the hull is cleaned, it is generally advantageous to also polish the propeller at the same time.

[0085] A primary objective of this disclosure is to generate a tool that is useful to operations teams in determining whether an operation would be beneficial for a particular vessel and whether that operation should be propeller sharpening, hull cleaning, or both.

[0086] Underwater operations are recognized as a high risk activity and are therefore subject to strict permit to work regimes. As mobilising dive teams is costly and vessels require time off in suitable ports, there is considerable benefit in being able to precisely target the timing and extent of any underwater activity.

[0087] The use of rolling data means that reports can be up to date at any time. The disclosed system and method can be included in a dashboard, allowing the selection of graphical options. Individual reports can be generated. Tests have verified predicted fuel savings that can be up to about 8-10%. The disclosed system and method provide better insight into the condition of the hull and propeller separately, allowing for more informed targeting of underwater operations and more informed evaluation of coatings. Overall, the system allows for forecasting of operation requirements.

[0088] The algorithms can be integrated into existing dashboards and performance can be displayed in real time. One example is when a vessel is used as a floating warehouse, as a result, some degree of fouling may occur if the vessel is at anchor for long periods of time.

[0089] The methods described herein may be implemented on any suitable system. Typically, the processor or controller runs an operating system, which may be, for example, a Windows-based operating system, such as the Windows NT, Windows 2000 (Windows ME), Windows XP, or Windows Vista operating systems available from Microsoft Corporation, the MAC OS System X operating system available from Apple Computer, the Enterprise Linux operating system available from Red Hat Inc., the Solaris operating system available from Sun Microsystems, or one of many Linux-based operating system distributions, such as UNIX operating systems available from a variety of sources. Many other operating systems may be used, and embodiments are not limited to any particular implementation.

[0090] The processor and operating system together define a computer platform on which application programs can be written in a high-level programming language. These component applications may be executable code, intermediate code (e.g., in C), byte code, or interpreted code that communicate over a communications network, such as the Internet, using a communications protocol such as TCP / IP. Similarly, aspects in accordance with the invention may be implemented using an object-oriented programming language such as .Net, SmallTalk, Java, C++, Ada, or C# (C Sharp). Other object-oriented programming languages ​​may also be used. Alternatively, functional programming languages, scripting languages, or logic programming languages ​​may be used.

[0091] Additionally, various aspects and features according to the present invention may be implemented in a non-programming environment, e.g., a document created in HTML, XML, or other format that renders the appearance of a graphical user interface or performs other functions when viewed in a browser program window. Furthermore, various embodiments according to the present invention may be implemented as programmed or non-programmed elements, or any combination thereof. For example, a web page may be implemented using HTML, and data objects called from within the web page may be written in C++. Thus, the present invention is not limited to a particular programming language, and any suitable programming language may be used. Furthermore, in at least one embodiment, the tools may be implemented using VBA Excel.

[0092] This improvement can be achieved without the need for additional hardware or sending data for expert interpretation. The process can be embedded into existing dashboards to get results, or can be performed in a simple stand-alone spreadsheet. Data sources can include simple midday reports or high frequency automated data.

[0093] Any natural improvement in performance as the vessel moves through the water can be tracked, giving greater insight into the degree of expected improvement, without work. Any work required can be pre-planned and can be specifically targeted to the hull, propellers, or both. The invention requires no additional hardware or data collection software. It can be applied to manual noon readings and is also suitable for incorporation into high frequency data systems.

[0094] The present disclosure is not limited to the above-described embodiments and the scope of the appended claims. Many modifications are possible within the scope of the appended claims. The features of each embodiment may be combined.

Claims

1. 1. A computer-implemented method for diagnosing maintenance needs for a sea-going vessel, the vessel comprising a hull, a propeller, an engine, and a drive shaft connecting the engine to the propeller, the method comprising: (a) calculating propeller distance using formula (A), Propeller Distance = (nominal pitch) * (number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A) The nominal pitch is a value indicating the pitch at a radius of 0.7, calculating the observed RPM, a value indicative of the number of revolutions per minute of the drive shaft over a selected period of time; (b) calculating a slip factor using equation (B), Slip coefficient = (propeller distance) / (observation distance) (B) calculating the observed distance, the observed distance traveled by the vessel over the selected time period; (c) outputting at least one of a propeller sharpening indicator and a hull cleaning indicator, outputting the propeller grinding indicator, - calculating a reference torque multiplier using formula (C), Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) ３ (C) the rated engine power is the maximum power output of the engine specified by the engine manufacturer; Calculating that the rated RPM is the maximum RPM of the propeller at the rated engine power specified by the engine manufacturer; - calculating the observed torque multiplier using equation (D), Observed Torque Multiplier = Observed Engine Power / (Observed RPM) ３ (D) calculating the observed engine power output of the vessel over the selected time period; - calculating the torque index using formula (E); Torque index = (number in the range of 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip coefficient) ２ (E) comparing said torque index to an upper torque index threshold; outputting the hull cleaning indicator, - calculating the slip index using formula (F), Slip index = (number in the range of 85 to 110) * (slip coefficient) ３ (F) - comparing said slip index with an upper slip index threshold; 11. A computer-implemented method comprising:

2. the step of outputting the propeller sharpening indicator further comprises: comparing the torque index to a lower torque index threshold and an upper torque index threshold; indicating that propeller sharpening would be beneficial if the torque index exceeds the lower torque index threshold but not the upper torque index threshold; and indicating that propeller sharpening is necessary if the torque index exceeds the upper torque index threshold; - the step of outputting the hull cleaning indicator comprises comparing the slip index with a lower slip index threshold and an upper slip index threshold, indicating that hull cleaning would be beneficial if the slip index exceeds the lower slip index threshold but not the upper slip index threshold, and indicating that hull cleaning is necessary if the slip index exceeds the upper slip index threshold; The computer-implemented method of claim 1 further comprising:

3. 2. The computer-implemented method of claim 1, further comprising adjusting at least the upper slip index threshold and optionally the lower slip index threshold over a period of time beginning when the vessel was last painted.

4. 2. The computer-implemented method of claim 1, further comprising: resetting at least the upper slip index threshold and optionally the lower slip index threshold when the vessel is painted.

5. 2. The computer-implemented method of claim 1, wherein the step of calculating the slip index comprises calculating a rolling average of the slip index over a period of time, optionally at least 15 days, more preferably 30 days.

6. 2. The computer-implemented method of claim 1, wherein the step of calculating the torque index comprises calculating a rolling average of the torque index over a period of time, optionally at least 15 days, more preferably 30 days.

7. 1. A computer program for diagnosing the need for maintenance on a seagoing vessel, the vessel having a hull, a propeller, an engine, and a drive shaft connecting the engine to the propeller, the computer program including instructions that, when executed by a computer, cause the computer to: (a) calculating propeller distance using formula (A), Propeller Distance = (nominal pitch) * (number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A) The nominal pitch is a value indicating the pitch at a radius of 0.7, calculating the observed RPM, a value indicative of the number of revolutions per minute of the drive shaft over a selected period of time; (b) calculating a slip factor using equation (B), Slip coefficient = (propeller distance) / (observation distance) (B) calculating the observed distance, the observed distance traveled by the vessel over the selected time period; (c) outputting at least one of a propeller sharpening indicator and a hull cleaning indicator, outputting the propeller grinding indicator, - calculating a reference torque multiplier using formula (C), Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) ３ (C) the rated engine power is the maximum power output of the engine specified by the engine manufacturer; Calculating that the rated RPM is the maximum RPM of the propeller at the rated engine power specified by the engine manufacturer; - calculating the observed torque multiplier using equation (D); Observed Torque Multiplier = Observed Engine Power / (Observed RPM) ３ (D) - calculating the torque index using formula (E); Torque index = (number in the range of 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip coefficient) ２ (E) - comparing the torque index with an upper torque index threshold, and outputting the hull cleaning indicator; - calculating the slip index using formula (F), Slip index = (number in the range of 85 to 110) * (slip coefficient) ３ (F) - comparing said slip index with an upper slip index threshold; A computer program that executes

8. the step of outputting the propeller sharpening indicator further comprises: comparing the torque index to a lower torque index threshold and an upper torque index threshold; indicating that propeller sharpening would be beneficial if the torque index exceeds the lower torque index threshold but not the upper torque index threshold; and indicating that propeller sharpening is necessary if the torque index exceeds the upper torque index threshold; - the step of outputting the hull cleaning indicator comprises comparing the slip index with a lower slip index threshold and an upper slip index threshold, indicating that hull cleaning would be beneficial if the slip index exceeds the lower slip index threshold but not the upper slip index threshold, and indicating that hull cleaning is necessary if the slip index exceeds the upper slip index threshold; The computer program of claim 7 further comprising:

9. 8. The computer program of claim 7, wherein the step of calculating the slip index comprises calculating a rolling average of the slip index over a period of time, optionally at least 15 days, more preferably 30 days.

10. 8. The computer program of claim 7, wherein the step of calculating the torque index comprises calculating a rolling average of the torque index over a period of time, optionally at least 15 days, more preferably 30 days.

11. 1. A computer-readable medium for diagnosing maintenance needs for a sea-going vessel, the vessel comprising a hull, a propeller, an engine, and a drive shaft connecting the engine to the propeller, the computer-readable medium comprising instructions that, when executed by a computer, cause the computer to: (a) calculating propeller distance using formula (A), Propeller Distance = (nominal pitch) * (number less than 1, preferably in the range of 0.7 to 0.99) * (observed RPM) (A) The nominal pitch is a value indicating the pitch at a radius of 0.7, calculating the observed RPM, a value indicative of the number of revolutions per minute of the drive shaft over a selected period of time; (b) calculating a slip factor using equation (B), Slip coefficient = (propeller distance) / (observation distance) (B) calculating the observed distance, the observed distance traveled by the vessel over the selected time period; (c) outputting at least one of a propeller sharpening indicator and a hull cleaning indicator, outputting the propeller grinding indicator, - calculating a reference torque multiplier using formula (C), Reference Torque Multiplier = (a number less than 1, preferably in the range of 0.8 to a maximum of 0.99) * (rated engine power) / (rated RPM) ３ (C) the rated engine power is the maximum power output of the engine specified by the engine manufacturer; Calculating that the rated RPM is the maximum RPM of the propeller at the rated engine power specified by the engine manufacturer; - calculating the observed torque multiplier using equation (D); Observed Torque Multiplier = Observed Engine Power / (Observed RPM) ３ (D) - calculating the torque index using formula (E); Torque index = (number in the range of 85 to 110) * (observed torque multiplier) / (reference torque multiplier) / (slip coefficient) ２ (E) - comparing the torque index with an upper torque index threshold, and outputting the hull cleaning indicator; - calculating the slip index using formula (F), Slip index = (number in the range of 85 to 110) * (slip coefficient) ３ (F) - comparing said slip index with an upper slip index threshold; A computer-readable medium for causing the computer to execute the method.

12. the step of outputting the propeller sharpening indicator further comprises: comparing the torque index to a lower torque index threshold and an upper torque index threshold; indicating that propeller sharpening would be beneficial if the torque index exceeds the lower torque index threshold but not the upper torque index threshold; and indicating that propeller sharpening is necessary if the torque index exceeds the upper torque index threshold; - the step of outputting the hull cleaning indicator comprises comparing the slip index with a lower slip index threshold and an upper slip index threshold, indicating that hull cleaning would be beneficial if the slip index exceeds the lower slip index threshold but not the upper slip index threshold, and indicating that hull cleaning is necessary if the slip index exceeds the upper slip index threshold; The computer-readable medium of claim 11 further comprising:

13. 12. The computer-readable medium of claim 11, wherein the step of calculating the slip index comprises calculating a rolling average of the slip index over a period of time, optionally at least 15 days, more preferably 30 days.

14. 12. The computer-readable medium of claim 11, wherein the step of calculating the torque index comprises calculating a rolling average of the torque index over a period of time, optionally at least 15 days, more preferably 30 days.

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