Learn how to use practical guidelines and tools to evaluate and enhance the reliability and redundancy of your dynamic positioning (DP) equipment.

An good example of this is that before commissioning our new Dynamic Positioning system on our offshore vessel, we conducted extensive reliability and redundancy testing. We performed factory acceptance testing to verify that the system met the manufacturer's specifications, as well as sea trials to test the system's performance in real-world conditions. We also conducted annual trials and emergency drills to ensure that the system would function properly in a variety of scenarios. Through these tests, we were able to identify and correct several minor issues, ultimately improving the system's overall reliability and performance.

How do you assess the reliability and redundancy of dynamic positioning equipment?

Dynamic positioning (DP) is a skill that enables vessels to maintain their position and heading using thrusters and propellers. DP is essential for offshore operations that require precise maneuvering and stability, such as drilling, surveying, or installing subsea equipment. However, DP systems are complex and vulnerable to failures that can compromise safety and performance. Therefore, it is important to assess the reliability and redundancy of DP equipment regularly and systematically. In this article, you will learn how to do that using some practical guidelines and tools.

1 Reliability and redundancy concepts

Reliability is the probability that a system or component will function as intended for a given period of time under specified conditions. Redundancy is the provision of backup or alternative systems or components that can take over the function of a failed one. Reliability and redundancy are interrelated, as redundancy can improve reliability by reducing the impact of failures. However, redundancy also adds complexity and cost to the system, and may introduce new failure modes or dependencies. Therefore, a balance between reliability and redundancy is needed to optimize the performance and safety of DP systems.

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William Britto

Experienced DP( Dynamic Positioning) & Bridge Navigation Systems Senior Service Engineer | 15+ Years in Field Service & Technical Training | Maritime Expertise
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The reliability of equipment is demonstrated through its consistent performance over time, validated across diverse scenarios and conditions. During the design phase, it's crucial to identify single-point failures and integrate redundancy principles accordingly. Certification of the design involves the class's participation, while a third-party assessment can carry out gaps in the design through a preliminary FMEA design report. For a DP2 or DP3 ship, redundancy is indispensable. Any failure of sensors, position reference systems, power, propulsion, or control systems should not lead to a loss of position or heading control.

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2 Reliability and redundancy analysis

Reliability and redundancy analysis is a process of evaluating the failure behavior and performance of DP systems using mathematical models and methods. There are different types of analysis, such as fault tree analysis, reliability block diagrams, failure mode and effects analysis, and Markov analysis. These methods can help identify the critical components and failure modes of the system, quantify the failure probabilities and consequences, and compare the reliability and redundancy of different design options or configurations. Reliability and redundancy analysis can also support the classification and certification of DP systems according to industry standards and regulations.

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3 Reliability and redundancy testing

Reliability and redundancy testing is a process of verifying the functionality and performance of DP systems using real or simulated scenarios and conditions. There are different types of testing, such as factory acceptance testing, sea trials, annual trials, and emergency drills. These tests can help validate the reliability and redundancy analysis results, demonstrate the compliance with the requirements and specifications, and identify any defects or deviations that need to be corrected or improved. Reliability and redundancy testing can also provide valuable feedback and lessons learned for the design, operation, and maintenance of DP systems.

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Irandy Assis

Dynamic Positioning Operator
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An good example of this is that before commissioning our new Dynamic Positioning system on our offshore vessel, we conducted extensive reliability and redundancy testing. We performed factory acceptance testing to verify that the system met the manufacturer's specifications, as well as sea trials to test the system's performance in real-world conditions. We also conducted annual trials and emergency drills to ensure that the system would function properly in a variety of scenarios. Through these tests, we were able to identify and correct several minor issues, ultimately improving the system's overall reliability and performance.

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4 Reliability and redundancy monitoring

Reliability and redundancy monitoring is a process of observing and measuring the condition and performance of DP systems during operation using sensors, indicators, alarms, and data logging. There are different types of monitoring, such as online monitoring, offline monitoring, condition monitoring, and performance monitoring. These monitoring methods can help detect any anomalies or failures that may affect the reliability and redundancy of the system, provide early warning and diagnosis, and enable timely intervention and recovery. Reliability and redundancy monitoring can also help track the degradation and wear of the system, and optimize the maintenance and repair schedules.

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5 Reliability and redundancy improvement

Reliability and redundancy improvement is a process of enhancing the functionality and performance of DP systems using various techniques and measures. There are different types of improvement, such as design improvement, operation improvement, maintenance improvement, and training improvement. These improvement methods can help reduce the frequency and severity of failures, increase the availability and robustness of the system, and mitigate the risks and costs of downtime or accidents. Reliability and redundancy improvement can also help adapt to the changing needs and challenges of the offshore industry, and leverage the opportunities and innovations of technology.

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William Britto

Experienced DP( Dynamic Positioning) & Bridge Navigation Systems Senior Service Engineer | 15+ Years in Field Service & Technical Training | Maritime Expertise
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Redundancy Improvement can be carried out with a series of proactive steps in increasing the reliability and confidence of the operator in the Dp system. Example of Position Reference Systems redundancy Ideally, a Platform Supply Vessel may have DGPS1 , DGPS 2, and a Laser-based Reference system. The addition of a Microwave-based reference system can add additional redundancy to the P.R.S. for its operations. Setting up the right thruster-power group along with the right switchboard configuration can adversely improve the redundancy of the Dp vessel.

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6 Reliability and redundancy resources

Reliability and redundancy resources are the sources of information and guidance that can help you assess and improve the reliability and redundancy of DP systems. There are different types of resources, such as standards, guidelines, manuals, reports, publications, software, tools, and training. These resources can help you understand the principles and practices of reliability and redundancy engineering, apply the appropriate methods and techniques for your DP system, and learn from the best practices and experiences of others. Reliability and redundancy resources can also help you stay updated and informed about the latest trends and developments in the DP field.

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William Britto

Experienced DP( Dynamic Positioning) & Bridge Navigation Systems Senior Service Engineer | 15+ Years in Field Service & Technical Training | Maritime Expertise
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Resources to refer for redundancy info - Standard DP Operating Procedures (vary form ship to ship) - FMEA ( Failure mode effective analysis) reports - OEM (customer acceptance test) reports - System Layout & Configuration setup -

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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How do you assess the reliability and redundancy of dynamic positioning equipment?

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1 Reliability and redundancy concepts

2 Reliability and redundancy analysis

3 Reliability and redundancy testing

4 Reliability and redundancy monitoring

5 Reliability and redundancy improvement

6 Reliability and redundancy resources

7 Here’s what else to consider

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