2.13. PRESCRIPTIVE MAINTENANCE

2.13.1 INTRODUCTION

2.13.1.1 DEFINITION

Prescriptive maintenance in marine engineering is an evolution of maintenance strategies, melding the foresight of predictive maintenance with the acuity of actionable recommendations. It is a holistic approach that forecasts potential maintenance issues and proactively suggests the best mitigation action. This strategy harnesses the power of advanced analytics, big data, artificial intelligence (AI), and machine learning algorithms to create a dynamic maintenance environment.

At its core, prescriptive maintenance in marine engineering leverages a wealth of data from various sources – including sensors on marine equipment, historical maintenance records, and operational parameters. This data is continuously collected and analysed in real-time. Unlike traditional maintenance approaches that rely on set schedules or reactive measures following a failure, prescriptive maintenance anticipates problems before they occur and recommends precise, evidence-based actions.

These recommendations are not generic; they are tailored to the specific circumstances of each vessel and its machinery. The system considers various factors, such as the current condition of equipment, the operational load, environmental conditions, and even the predicted future usage of the vessel. Doing so can suggest the most effective maintenance actions, whether immediate repairs, scheduled downtime, or adjustments in operation to prolong equipment life.

Integrating AI and machine learning allows the system to learn from each intervention, improving its accuracy and effectiveness. This learning capability means the system becomes more adept at identifying subtle patterns or signs of impending issues that human operators or simpler predictive models might miss.

Prescriptive maintenance in marine engineering is about moving beyond simply predicting problems to providing actionable, intelligent solutions that optimise the performance and longevity of marine vessels and their equipment. It represents a paradigm shift from reactive or even predictive maintenance to a more sophisticated, data-driven approach that empowers marine engineers to make informed, strategic decisions that enhance efficiency, safety, and cost-effectiveness in marine operations.

2.13.2 KEY COMPONENTS OF PRESCRIPTIVE MAINTENANCE

2.13.2.1 REAL-TIME DATA MONITORING AND ANALYSIS

In prescriptive maintenance, real-time data monitoring and analysis stand as the foundation. Advanced sensors and Internet of Things (IoT) devices are deployed extensively across marine vessels, continuously gathering data from various components like engines, navigational systems, and hull structures. This data, ranging from temperature readings to vibration analysis, is then transmitted in real-time for analysis.

The analysis involves sophisticated algorithms and data analytics tools that scrutinise this data stream for anomalies, trends, and patterns. This process detects issues and predicts future problems based on subtle changes in data readings. For instance, a slight increase in engine temperature or a minor change in vibration patterns could indicate a potential future failure. By identifying these issues early, prescriptive maintenance allows for interventions that prevent more significant problems and costly repairs.

 

2.13.2.2 DECISION SUPPORT SYSTEMS (DSS)

Decision Support Systems (DSS) are integral to prescriptive maintenance. These systems take the analysis provided by real-time monitoring and use it to offer actionable maintenance recommendations. DSS in marine engineering is multifaceted; it incorporates data analytics, expert systems, and sometimes even AI to process the data and provide well-rounded advice.

The strength of a DSS lies in its ability to consider a wide array of factors before making a recommendation. These factors include the cost implications of different maintenance actions, the required time, the availability of resources (like spare parts or technical personnel), and the potential impact on vessel operations. By balancing these variables, a DSS ensures its maintenance actions are timely, cost-effective, and resource-efficient.

2.13.2.3 FAILURE MODE AND EFFECTS ANALYSIS (FMEA)

Failure Mode and Effects Analysis (FMEA) is a systematic, structured approach for analysing potential reliability problems at the earliest stages. In marine engineering, FMEA involves a detailed examination of aquatic systems and components to identify all possible failure modes, their causes, and their effects on the overall system's performance.

FMEA in prescriptive maintenance is proactive. It aims to identify potential failure points before they occur, understanding how and why these failures might happen and the consequences thereof. This analysis helps prioritise maintenance tasks by highlighting the most critical areas that need attention. It also aids in developing strategies to mitigate risks, thereby enhancing the safety and reliability of marine systems.

2.13.2.4 MAINTENANCE SCHEDULING OPTIMISATION

The final key component is the optimisation of maintenance scheduling. This aspect uses algorithms and predictive models to determine the most opportune times for conducting maintenance activities. These algorithms consider various factors, such as the condition of equipment, predicted failure rates, operational schedules of the vessel, and even external factors like weather conditions and port availability.

Maintenance scheduling optimisation ensures that maintenance activities are conducted on time (which can be wasteful) or too late (which can lead to failure and operational disruptions). By finding the optimal balance, this component of prescriptive maintenance maximises equipment uptime, enhances operational efficiency, and reduces costs associated with unscheduled downtimes and emergency repairs. It is a strategic approach that aligns maintenance activities with the vessel's operational requirements and constraints, ensuring smooth, uninterrupted marine operations.

2.13.3 BENEFITS OF PRESCRIPTIVE MAINTENANCE

2.13.3.1 INFORMED DECISION-MAKING

One of the most significant benefits of prescriptive maintenance is its role in fostering informed decision-making. This approach provides a detailed, data-driven view of the health and performance of marine equipment and systems. By leveraging the insights gained from continuous monitoring and advanced analytics, marine engineers and decision-makers are equipped with a comprehensive understanding of their vessel's operational status. This knowledge allows them to preempt failures before they occur and make decisions that optimise performance. For instance, if data indicates an emerging problem in the engine room, decisions can be made to address the issue during a scheduled docking rather than facing an unexpected failure at sea.

2.13.3.2 OPTIMISED MAINTENANCE OPERATIONS

Prescriptive maintenance also leads to more optimised maintenance operations. Traditional reactive maintenance often results in unplanned downtime and rushed, costly repairs. In contrast, prescriptive maintenance uses predictive analytics to time maintenance activities precisely, ensuring that interventions are carried out when they are most effective and least disruptive. This approach minimises downtime and ensures that maintenance tasks are performed on time. The result is a smoother, more efficient operational workflow, seamlessly integrating maintenance activities into the vessel's schedule.

2.13.3.3 ENHANCED SYSTEM RELIABILITY

Enhancing system reliability is a core advantage of prescriptive maintenance. This strategy proactively addresses potential issues, preventing equipment failures before they occur. Doing so significantly reduces the risk of unexpected breakdowns and ensures all systems function optimally. Enhanced reliability is not just about preventing failures; it's also about ensuring that the vessel operates at peak efficiency, which is crucial for safety and operational success in the demanding marine environment.

2.13.3.4 COST SAVINGS

Finally, prescriptive maintenance can lead to substantial cost savings. The proactive nature of this maintenance strategy means that issues are often resolved before they escalate into major problems, thus avoiding expensive emergency repairs. Additionally, the overall operational costs are lowered by reducing downtime and extending the life of equipment through timely and precise maintenance interventions. This cost-effectiveness is a significant benefit, especially regarding the high operational costs associated with marine vessels. The savings achieved through prescriptive maintenance can be redirected towards other critical areas of marine operations, further enhancing the efficiency and profitability of maritime enterprises.

2.13.4 EXAMPLES

2.13.4.1 PRESCRIPTIVE MAINTENANCE FOR DUAL FUEL MAN B&W MAINE ENGINE

Take the case of an Aframax tanker equipped with a dual-fuel MAN B&W main engine. This type of engine, capable of running on traditional marine fuels and liquefied natural gas (LNG), presents unique maintenance challenges due to its complex fuel systems and combustion processes.

The vessel's management can more effectively optimise fuel usage and anticipate maintenance needs by implementing prescriptive maintenance. For example, sensors embedded in the engine can monitor parameters such as fuel pressure, exhaust gas composition, and cylinder temperatures in real-time. When analysed, this data can indicate wear or inefficiencies in fuel combustion.

It can suggest a specific action if the system detects an anomaly, like a higher-than-normal exhaust gas temperature. This might include adjusting the fuel injection timing or planning a detailed inspection of certain engine components during the next port call. Such actions prevent unexpected engine failures and ensure the engine operates efficiently, reducing fuel consumption and emissions - crucial for compliance with international maritime regulations.

In a real-world scenario, this could mean the difference between a smooth, uninterrupted voyage and an unscheduled stop due to engine failure, significantly impacting the tanker's operational costs and reliability.

2.13.4.2 PRESCRIPTIVE MAINTENANCE FOR HULL (TANKER)

Consider an Aframax tanker navigating global trade routes, where its hull is subjected to various stress factors like varying sea conditions, temperature fluctuations, and corrosive environments. Prescriptive maintenance can be particularly beneficial in maintaining the hull's integrity.

Through the integration of hull stress monitoring systems and corrosion detection sensors, prescriptive maintenance can predict areas on the tanker's hull that are prone to corrosion or structural stress. For example, sensors might detect increased corrosion activity levels in certain hull sections, potentially caused by a coating failure or an electrochemical reaction.

Upon analysing this data, the system might suggest a targeted inspection and maintenance plan for the affected area during the next dry docking. It could also recommend adjustments to voyage routes or speeds to reduce stress on vulnerable hull sections. Additionally, the analysis might indicate the need for a different type of protective coating or anodic protection system in the future.

In a practical scenario, this level of detailed, proactive maintenance can prevent structural failures, which are critical in maintaining the safety and integrity of the vessel. It also ensures compliance with maritime safety standards and can significantly reduce the costs associated with significant hull repairs. For an Aframax tanker, this approach not only guarantees structural safety but also enhances the operational efficiency and longevity of the vessel.

2.13.5 CONCLUSION

Prescriptive maintenance marks a revolutionary stride in marine engineering maintenance. This approach, underpinned by integrating advanced analytics and real-time data acquisition, transcends traditional maintenance methodologies. It embodies a proactive, predictive, and precise strategy that substantially augments operational efficiency, elevates safety standards, and bolsters cost-effectiveness in the demanding sphere of marine engineering.

In the dynamic and often unpredictable environment of marine operations, where vessels are subject to diverse and harsh conditions, the importance of a maintenance strategy that can predict and prescribe cannot be overstated. Prescriptive maintenance leverages cutting-edge technologies like IoT, AI, and machine learning, transforming vast data sets into actionable insights. These insights empower marine engineers and decision-makers with the foresight to preemptively address potential issues before they escalate into costly and hazardous situations.

The implementation of prescriptive maintenance strategies, as illustrated in the examples of dual-fuel MAN B&W main engines and Aframax tanker hulls, demonstrates its effectiveness in enhancing the reliability and longevity of critical marine systems. By optimising maintenance operations, reducing unplanned downtimes, and extending equipment life, prescriptive maintenance contributes to a significant reduction in operational costs. More importantly, it plays a crucial role in ensuring the safety of the vessel, its crew, and the marine environment.

In summary, prescriptive maintenance is a cornerstone in advancing marine engineering maintenance. It is not merely an improvement over existing maintenance practices but a transformative approach that aligns with the evolving needs of modern marine operations. By adopting prescriptive maintenance, the maritime industry is better equipped to navigate the complexities of today's marine environment, ensuring smoother, safer, and more efficient voyages across the world's oceans.

 

Disclaimer:

Out of Box Maritime Thinker © by Narenta Gestio Consilium Group 2022 and Aleksandar Pudar assumes no responsibility or liability for any errors or omissions in the content of this paper. The information in this paper is provided on an "as is" basis with no guarantees of completeness, accuracy, usefulness, or timeliness or of the results obtained from using this information. The ideas and strategies should never be used without assessing your company's situation or system or consulting a consultancy professional. The content of this paper is intended to be used and must be used for informational purposes only.