At MTSea we are passionate about the quality of air that you breathe onboard your yacht.  We are frequently asked to go aboard to offer advice on the ventilation system, time and time again we find ventilation systems that are not working at their optimum due to poor design, poor installation or modifications that have been made over time. The current COVID-19 situation has highlighted the need for good ventilation in interior spaces.

US Environmental Protection Agency says that: –

COVID-19 is thought to spread mainly through close contact from person-to-person. However, some uncertainty remains about the relative importance of different routes of transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). Evidence now confirms that this virus can remain airborne for longer times and further distances than originally thought. In addition to close contact with infected people and contaminated surfaces, spread of COVID-19 may also occur via airborne particles in indoor environments, in some circumstances beyond the 2 m range encouraged by some social distancing recommendations. 

There are straightforward steps that can be taken to reduce the potential for airborne transmission of COVID-19 and the focus of this material is on those measures. The layout and design of a building (yacht), as well as occupancy and type of heating, ventilation, and air conditioning (HVAC) system, can all impact potential airborne spread of the virus. Although improvements to ventilation and air cleaning cannot on their own eliminate the risk of airborne transmission of the SARS-CoV-2 virus, EPA recommends increasing ventilation with outdoor air and air filtration as important components of a larger strategy that includes social distancing, wearing cloth face coverings or masks, surface cleaning and disinfecting, handwashing, and other precautions. By themselves, measures to reduce airborne exposure to the virus that causes COVID-19 are not enough since airborne transmission is not the only way exposure to SARS-CoV-2 could potentially occur.

What can be done on a yacht regards airborne transmission

Increase Ventilation with Outside Air

While it is not always easy to leave doors, hatches and portlights open to increase ventilation on a yacht, consider what is safe and possible and make it standard practice.

If you have an air-make system make sure it is working at its best. Check the filters are clean, fit properly, are of good quality and are in good condition. Check the parameters to ensure there is a good turnaround of air coming into the yacht also consider having the system checked professionally.

The MCA Large Yacht Code states the ventilation system should provide 6 changes of air per hour (with all outside openings closed) this is outside air coming into the accommodation spaces. Blocked filters, dirty or old fans, and restrictions in ducting will all reduce the efficiency of the air make up units.  We also find piecemeal modifications made to the system often impair the efficiency by increasing or decreasing air flows at particular points. It is possible to professionally check air flows to ensure that your system is free of this type of problem. Also incoming air should be dried through a heat exchanger to remove moisture from the ambient air, this can also be professionally checked to ensure good function and that the settings are at optimum. Where there is no air make and the yacht is experiencing problems take advice on whether retro fitting an air make up unit is possible.

Filter the Air

Where it is not possible to leave doors and hatches open run your HVAC (heating, ventilation and air conditioning) system continuously so it filters the air as it is circulated, this can help reduce airborne contaminants, including viruses. The fans can still be run even if the heating or cooling is not being used.

Air Quality

Signs of poor general ventilation in an indoor space include musty smells, constant moisture on surfaces, mould, rooms are dusty, difficulty in heating or chilling the room and people seem to get colds frequently. Listen to complaints related to draughts and temperature, do people often get cold feet? This is an indication that there is inadequate airflow as the cold air from the AC is sinking to the floor and not being circulated around the room.

Simple monitoring of the CO2 levels in a room can tell you a lot about air quality and efficiency of the system you have on board. Where ventilation is good, CO2 will not build up. Monitoring can not only help identify system problems but it can also warn you that at any particular moment the system you have is overwhelmed by the number of people in the room and it is therefore time to disperse.  In this case a yacht could use a simple, cheap CO2 monitor to act as an alarm in their communal areas.

MTSea is able to provide a whole yacht air quality survey to help you understand the efficiency of your HVAC system and discuss recommendations for improvement where needed.

Other Precautions

By itself, running your HVAC system is not enough to protect people from the virus that causes COVID-19, it should be used alongside other best practices recommended by WHO which include: –

• Make wearing a mask a normal part of being around other people.
• Clean your hands often
• Cough or sneeze in your bent elbow – not your hands!
• Avoid touching your eyes, nose and mouth
• Limit social gatherings and time spent in crowded places
• Avoid close contact with someone who is sick
• Clean and disinfect frequently touched objects and surfaces
• Improve ventilation