What type of light is required for a vessel less than 7 metres in length?

For vessels that are less than 7 meters in length, the requirements for navigation lights are simplified due to their small size. According to the COLREGs (International Regulations for Preventing Collisions at Sea), these vessels are not required to display navigation lights when at anchor or underway in certain conditions, such as when they are not engaged in fishing.

The rationale behind this is that smaller vessels typically enjoy certain exemptions due to their limited impact on navigation and the lower risk they pose in busy shipping channels. Therefore, there is no obligation for them to show sidelights, masthead lights, or any specific light configuration under most circumstances.

It is important to note that even though these small vessels may not be legally required to carry lights, it is good practice to have some form of lighting to increase visibility and safety, especially in poorly lit conditions or when operating in areas with larger vessels. However, under the strict regulations of the COLREGs, the correct answer is that no lights are required for a vessel less than 7 meters in length when not constrained by their size or other operational requirements.