Observing a light across the water, the captain had his signalman instruct the other vessel to change her course ten degrees south.
The response was prompt: Change your course ten degrees north.”
“I am a captain,” he responded testily. “Change your course ten degrees south.”
The reply: “I’m a seaman first class, sir; change your course north.”
The captain was furious. “Change your course now. I’m on a battleship.”
“Change your course ten degrees north, sir — I’m in a lighthouse!”