New DNV guidance on managing blackout risks on passenger ships highlights importance of safety focus

A newly published guidance paper from DNV seeks to support the prevention and mitigation of blackouts impacting passenger vessels.
With blackout incidents on cruise ships on the rise, DNV has created a new guidance titled ‘Managing the risk of blackouts’ which addresses the main causes and associated risks, while offering recommendations and best practices on how to avoid them and reduce the likelihood of their occurrence, according to the company's release.
 
In 2019 there were 12 reported power-loss events on cruise ships that resulted in full or partial blackout while in transit or manoeuvring – up from four events in 2018. Although the majority of incidents occur in open water with minimal consequences, they represent a major accident hazard and, in certain situations, result in loss of propulsion which may pose an imminent threat to the ship, its passengers and crew.
 
While in recent years there has been a lot of focus on sustainability factors and cost saving measures, DNV urges owners and operators not to lose sight of the safety element.
 
In the new paper, DNV outlines a stepwise approach that centres on a simplified barrier-risk model. A simplified ‘bow tie’ model is used to present the threats and technical/operational barriers that contribute to increasing/decreasing the likelihood of blackout, and the mitigating barriers for supporting recovery. The paper’s five-step structure makes the information and practical tools easy to access and implement.
 
In summary, the guidance paper is intended to support a step-change in safety for operators, from gaining an overall understanding of blackout causes, defining safety ambitions and prudently managing conflicting goals (such as decarbonization and cost pressures), to identifying appropriate operational and technical measures to reduce risk based on cost-benefit evaluations.
 
The paper also describes the mandatory requirements for blackout prevention and recovery that provide a minimum technical standard for newbuildings, including Safe Return to Port (SRtP) regulations under SOLAS and additional measures such as DNV’s Operational Reliability (OR) class notation, which specifically targets resilience and availability of propulsion, steering, electrical power and manoeuvrability.
 
DNV is the world’s leading classification society and a recognized advisor for the maritime industry.