So far, nothing had been seen or heard of the Raven, but a strict watch was kept each day for the Hankers' vessel.
But one more stop was to be made, at the island of San Murio, and then the Swallow was to proceed directly for the locality where the treasure ship Happy Hour had gone down.
Day after day passed and nothing of importance occurred.
One afternoon there was some slight break in the machinery and the ship had to come to a stop for a couple of hours while repairs were being made.
It was a hot day and several of the sailors readily obtained permission to go in swimming.
"I think I will join them," said Dave to his father. "The water looks cool and tempting."
"All right, Dave," was the answer. "But take care you don't get a cramp."
"If I do, you can bet I'll yell for help," laughed the young diver.
He was soon in the water and sporting around to his heart's content.
The sailors had allowed one of the small boats to drift astern, and Dave swam to this and showed several of them how to make deep dives and long stretches under the ocean's surface.