"Know anything about water or boats?" the captain asked, after an interval.
"I've been used to little sailboats and canoes all my life, sir, and I can swim."
Alec might have added that he was the champion swimmer of the Central City High School, but he wisely did not.
"Well," rejoined the captain, "that may be useful to you. There are too many sailors who cannot swim."
"Sailors who cannot swim," repeated Alec in astonishment. "Why, I supposed all sailors could swim."
"Then you supposed wrong. Lots of 'em can't swim a stroke."
The captain thrust his head out of a window and surveyed the water. "Tide's about run out," he said.
Alec noticed that the water below them was moving much slower than it had been. Accustomed as he was to an inland stream, in which the current always ran one way, the alternating flow of this tide-water stream interested him deeply. As he looked at the banks of the river, he could see that the water had fallen several feet.
"How much does the tide fall here?" he asked.