What is the minimum visibility of an all-round light on a vessel of 20m in length?

The correct answer pertains to the regulations set forth in COLREGs (International Regulations for Preventing Collisions at Sea), which stipulate the minimum visibility requirements for navigation lights on vessels of various sizes. For vessels that are 20 meters in length, an all-round light must be visible from a minimum distance of 2 nautical miles. This requirement ensures that other vessels can clearly see the presence and direction of the vessel, significantly contributing to navigational safety, especially in reduced visibility conditions.

Understanding this specific regulation is crucial for maintaining safe passage at sea. For larger vessels, such as those over 50 meters, the visibility ranges increase accordingly to enhance safety measures. In contrast, smaller vessels have different visibility requirements, often set to a shorter range than that specified for larger ones. This context highlights the necessity of size-appropriate lighting to optimize safety for both the vessel and other mariners.