Regulations clearly stipulated against it. An exposed light in the middle of the darkness, especially on the open sea when the country was at war made the vessel emitting the light extremely vulnerable. German U-boats could spot it in a second, and attack in the next. And the risk was made extremely clear to merchant navy man Jim Hunt during one North Atlantic crossing when his tanker convoy was under an escort by U.S. navy ships.

“Someone had left a porthole open with a light on at dusk on board our tanker,” Hunt said, remembering his time in the Second World War as a teenaged sailor at sea aboard a Norwegian merchant navy ship. “So, an American destroyer came alongside our ship and signaled for us to turn the light out … or they would sink us.” (more…)