Maritime operational risk management using dynamic barriers

Abstract

The safe operation of any vessel is challenged by the constraints posed through design as well as maintenance and correct operation of the available safety barriers to ensure their effectiveness. This requires a direct linkage between barrier performance and operational risk management, accounting for potential degradation of the barriers and ensuing corrective actions. Therefore, the introduction of dynamic barrier management is a powerful tool in maintaining design resilience during operation and in emergencies. It is the purpose of this paper to demonstrate the achieved progress in developing a comprehensive approach to address risk in real-time. The authors aim to show how performance information on barrier elements and their respective functions is a) collated, b) aggregated through parametric (empirical) models for identifying barrier relative importance, function criticality and in defining a set of key safety indicators, and c) is intuitively visualized for providing real-time guidance to crew and shoreside management. The practicality of this approach is demonstrated by considering watertight doors as dynamic barriers preventing excessive transient-and progressive-flooding on a cruise vessel during operation. It will be discussed how these methods can be generalized into a framework, enabling operational risk management and subsequent decision support.

A framework for onboard assessment and monitoring of flooding risk due to open watertight doors for passenger ships

“…Historical data on WTD status was not available for the analyzed ship, hence artificial door status signals were needed for testing and demonstration purposes. Previously, in [23], generated door status signals have been used based on assumed probability distributions for each WTD category. For category "C" doors this approach is reasonable, if the doors are opened only to allow a person to pass through.…”

“…ship flooding), which follows conventional definition of risk as a combination of accident likelihood and consequences, [19][20][21]. This leads to risk mitigation measures aiming to prevent accidents, or to reduce their consequences [22,23]. The literature on risk of maritime transportation systems includes various risk assessment methods and tools that address these aspects independently, but rarely in a combined format [22,24].…”

“…A natural extension of the existing vulnerability assessment solutions would be a framework for the operational assessment of flooding accident susceptibility of passenger ships resulting from collision or grounding, accounting for relevant contributing factors. Continuous assessment of both ship vulnerability and susceptibility is an element of a dynamic safety barrier that tends to increase the crew's situational awareness and ship safety via the safe operation of watertight doors, as recently elaborated and demonstrated in [23]. Despite combining susceptibility with vulnerability, the solution proposed in [23] does not offer any novel or principles-driven approach to monitor the safety of ship in a proactive manner accounting for relevant and observable factors.…”

“…Continuous assessment of both ship vulnerability and susceptibility is an element of a dynamic safety barrier that tends to increase the crew's situational awareness and ship safety via the safe operation of watertight doors, as recently elaborated and demonstrated in [23]. Despite combining susceptibility with vulnerability, the solution proposed in [23] does not offer any novel or principles-driven approach to monitor the safety of ship in a proactive manner accounting for relevant and observable factors. Instead, it utilizes statistics, which in this case are not applicable, as they do not reflect actual operational conditions.…”

On the use of leading safety indicators in maritime and their feasibility for Maritime Autonomous Surface Ships

“…Therefore monitoring properly set-up quantities that remain in causational relation to the negative albeit yet unrecorded outcomes (accidents), that are observable and manageable is an example of proactive and dynamic safety management strategy. 32…”