Two battleships assigned to the training squadron had been at sea on maneuvers in heavy weather off the California coast for several days. As night fell, the captain noticed the patchy fog and decided to remain on the bridge.
Shortly after dark, the lookout on the wing of the bridge reported, "Light. Bearing on the starboard bow."
"Is it steady or moving astern?" the captain asked.
The lookout replied, "Steady, captain," which meant the battleship was on a collision course with the other ship.
The captain called to the signalman, "Signal that ship. You are on a collision course. Advise you alter course 20 degrees."
Back came the answering signal, "Advisable that you change course 20 degrees."
The captain said, "Send another message. I am a senior captain. Change course 20 degrees."
"I am a seaman second class," came the reply, "Change your course at once."
The officer was furious. He spat out, "We are a battleship squadron. Change your course 20 degrees."
The flashing light replied, "I am a lighthouse." The squadron changed course.
[Attributed to Proceedings of the U.S. Naval Institute, via Lighthouse Prose.]
Lesson: Know which light you are, and which light you're looking at. Be prepared to change course.