Diving is a high-risk work operation that requires strict safety measures, both from the diver and the surrounding environment. The Norwegian Maritime Authority (NMA) has recently received reports of vessels passing to close to the diver flag. Thie “lessons learned” therefore focuses on what the flag means and how we can all help protect those working underwater.
Background
Diving is inherently a high-risk activity. Divers are exposed to pressure changes, physical strains, cold, currents and technical challenges that can have serious health consequences if something fails. The NMA occasionally receives reports of accidents in connection with diving operations. Incidents have included divers getting entangled in tools and ropes during work.
A report from the Marine Accident Investigation Branch (MAIB) shows how lack of visibility and communication can have tragic consequences. In 2023, a recreational diver died in Scapa Flow when the support vessel Karin passed over him without detecting his ascension buoy. The diver was marked using DSMB (Delayed Surface Marker Buoy), but the vessel did not see the marker. The incident reminds us of the importance of using clearly visible diving flags and buoys, and ensuring that all vessels in the area are informed that diving is taking place. Proper marking, clear communication between vessels and vigilant lookout are essential for safe diving.
The regulations governing occupational diving are therefore strict, requiring everything from competence, staffing and planning to equipment, communication, record-keeping and emergency preparedness. Shipowners and employers must ensure that the working environment is fully safe, and the Norwegian Labour Inspection Authority’s regulations emphasise that diving operations must always be based on thorough risk assessments and clear safety procedures (Norwegian Labour Inspection Authority, 2025).
Importance of the diver flag
Even though shipowners or employers do their part to keep divers safe at work, the NMA has received tips from the industry that surrounding vessels do not always respect the warning signals. Recently, there have been several cases where the diver flag was raised, but the industry has observed that vessels still approached too close to diving boats. So we though it would be a good idea to illustrate what the flag looks like.
When you see this flag raised, it means a diver is working underwater. A diver can be as far as 300 metres from the support or diving boat (Norwegian Maritime Authority, 2017). Boat operators, both professional and recreational, are reminded of their duty to respond correctly when they see the diver flag: reduce speed, keep distance and stay alert for divers below. This assumes that the shipping company or vessel conducting diving operations has places the flag where it is clearly visible to other vessels (Regulations on diving from ships, 2020).
If you are unsure about the distance you should keep from a vessel displaying the diver flag, contact them directly on VHF channel 16. Clear communication between vessels is crucial to avoid accidents. The NMA has previously emphasised the importance of this in “Lessons learned – communication between vessels”.
A vessel coming too close to divers adds extra risk on top of the inherent risks of the diving work. Passing a flag without taking precautions undermines the safety barriers that regulations are built on, exposing an otherwise well-planned operation to unnecessary hazards.
Report risks at sea
This note aims to prevent accidents and near misses. The NMA greatly appreciates tips from both the industry and private individuals about risk conditions at sea. Our work towards the vision of zero fatalities and zero serious injuries depends on having a communication channel with those at sea that is based on trust and has a low threshold for reporting. We encourage others to do the same!