COVID-19 transmission inside a small passenger vessel: risks and mitigation

Abstract

The global shipping industry has been severely influenced by the COVID-19 pandemic; in particular, a significant amount of passenger transportation has been suspended due to the concern of COVID-19 outbreak, as such voyages confine a dense crowd in a compact space. In order to accelerate the recovery of the maritime business and minimise passengers’ risk of being infected, this work has developed a computational model to study the airborne transmission of COVID-19 viruses in the superstructure of a full-scale passenger vessel. Considering the vessel advancing in open water, simulations were conducted to study the particulate flow due to an infected person coughing and speaking, with the boat’s forward door open and closed. The results have shown that, when the forward door is open, a significant airflow is generated within the boat, which can carry the viruses to make extensive contacts with the passengers, leading to the suggestion of keeping the forward door closed; when the forward door is close, virus particles may not transmit a distance further than a seat’s length, before sinking to attach to the deck, based on which, an alternate seat arrangement is suggested. Furthermore, investigations were conducted on the influence of wall-mounted Air Conditioner (AC) on the virus transmission, and it was found that controlling the AC wind direction at less than 15° downward can effectively limit the virus spread. Meanwhile, it is demonstrated that an AC’s backflow tends to gather virus particles in a nearby area, thus sitting farther from an opening AC can reduce the risk of being infected. Overall, this work is expected to inform hygienic guidelines for operators to counter COVID-19 and potentially similar viruses in the future.