Thousands of ships cross the oceans, fish along the continental shelf, and transport passengers and cargo along the coasts. The International Regulations for Preventing Collisions at Sea established in 1972 stipulate that every modern merchant vessel and warship must be equipped with navigation lights. The lights must be kept on from sunset to sunrise.

For hundreds of years, ships sailed without such lights. The number of ships was smaller, and the risk of collision at night was not considered a significant concern. Those involved in shipping were more concerned with building lighthouses on dangerous rocky and shallow shores rather than equipping ships with lights.

By the mid-19th century, there was already a vast fleet of military and commercial ships. Shipping routes became crowded. In busy areas like the approaches to seaports in Northern Europe, straits, the North Sea, the Baltic Sea, and the east coast of North America, many difficulties arose. Particularly challenging were the conditions for captains sailing in these waters at night or in fog.

In 1852, the British Admiralty adopted a regulation requiring all British and foreign vessels approaching within 20 miles of the British Isles to keep running lights on at night. Under this regulation, any losses resulting from a collision were compensated by the owners of the ship that failed to comply with the rules. Soon, other maritime nations followed suit.

In 1889, the United States convened the first International Maritime Conference to consider regulations for preventing collisions. It was attended by representatives from 26 maritime nations. Most of the rules adopted at the conference continue to be in effect to this day. Nowadays, blue lights are used by navy ships.

The blue running light from the museum collection, which was used for self-propelled and non-self-propelled vessels, was produced around the turn of the 20th century. There is an inscription in English on its body that reads “STARBOARD”.