"I don't know. Anyway, they're suspicious. Did you find anything?"
"Just as you signaled. How did you signal, by the way?"
"With the mop pail. Four taps with the bottom on the water surface. Then I filled the pail and began swabbing down."
Rick nodded. "I don't know what I found. A cylinder, maybe two inches in diameter, maybe less. Smooth. I got the fish line around it and carried the line to the shore. We'll have to come back later."
"We certainly will." Scotty's eyes sparkled. "But for now, let's up anchor and get out of here."
"How about the stake with the rope on it?"
"The tide's still coming in. It will be completely under the water at high tide. We'll have to avoid it, and warn Harris if we don't get back tonight."
An idea was beginning to form in Rick's mind. "Okay," he said. "Let's get going."
Within minutes the houseboat was on its way out of the cove, the two boys acting normally, as though no one was observing their departure. Rick saw no one on shore, and not until they were sunward from the cove entrance did he see the sparkle of sunlight on binocular lenses. Scotty had been right, as usual.