Puzzle

A riverboat is proceeding full throttle upstream against a 10 knot current.

The Captain asks the First Mate, "How do we look for Bartlestown, Mr. Bentley?"

The Mate answers, "One hour sir. Bit ahead of time. We are making 20 knots over water."

Just then the wind caught the hat of a lady and blew it into the water. "Oh dear," she exclaimed, "my grandmother’s hat. I must ask the Captain to turn around." She proceeded to the Captain and begged him to turn around to get her hat.

"Turn about Helmsman," the Captain said.

Assume from the time the hat blew into the water until the time the boat started its turn-about was one minute. Assume that it takes half a minute to turn the boat around. How many minutes are lost in getting to Bartlestown?

Hint: This problem is sometimes given to students starting a study in the Special Theory of Relativity. You need to consider two frames of reference: the shore frame and the river frame. Attacked with this in mind, the problem is simple.