What is the minimum whistle sound pressure level for vessels of 20 meters or more?

The minimum whistle sound pressure level for vessels of 20 meters or more is set at 120 dB. This high decibel level is essential for ensuring that the sound can carry effectively over long distances, which is crucial for maritime safety and communication, especially in conditions where visibility may be limited, such as fog or heavy rain. Larger vessels are expected to be heard over a significant range, therefore the stringent requirement of 120 dB helps to ensure that the distress signal is audible to nearby vessels, helping to prevent collisions and enhancing the overall safety at sea. The standards are part of international regulations to ensure that all vessels can effectively communicate and signal distress as necessary.