What type of vessel must display one light higher and abaft when over 50 meters in length?

A trawling boat, when over 50 meters in length, must display one light higher and abaft to indicate its status when engaged in fishing activities. This lighting configuration is essential for ensuring that other vessels are aware of its fishing operations, as the light signals provide information on the direction and activity of the trawler.

The requirement for additional lights is part of international regulations aimed at promoting safety on the water by allowing other mariners to recognize the operational state of the vessel. In terms of size and type, larger fishing vessels such as trawlers are specifically addressed in the maritime rules, focusing on their need for clear signal visibility to avoid accidents during night operations or in poor visibility conditions.

While fishing vessels, sailing vessels, and cargo vessels have their own lighting requirements, the specific mention of a "trawling boat" in relation to the height and positioning of lights is what makes that choice relevant to the question about vessels over 50 meters in length.