Tom joined in the fun, and soon a rollicking game of underwater tag was in full swing. The dolphins seemed as playful and mischievous as small children.
Twenty minutes later the boys surfaced and hauled themselves aboard. Both tore off their masks and flopped into the boat, shaking with laughter, surfacing and diving.
"What was so funny down there?" Zimby asked.
When Tom told him about the dolphins, he too burst into laughter. The porpoises rose into view and convoyed the launch all the way back to the island.
The boys were so jubilant over the performance of the new hydrolung gear that Tom decided to press his search for the Brungarian sea-prowlers immediately. Soon after lunch they took off in the Sea Hound and headed for the South Atlantic. Hank Sterling, Chow Winkler, and two crewmen accompanied the boys.
Dazzling afternoon sunshine sparkled over the sea when they reached the missile search area. Tom immediately contacted Art Wiltessa and the task-force ships. They had no new developments to report.
The young inventor gave orders to submerge. As soon as the seacopter touched bottom, Tom and Bud swam out through the air lock with their hydrolungs.
They probed about for half an hour, ranging farther and farther from the Sea Hound. Then Tom felt a touch on his arm. He turned and saw Bud pointing off excitedly to the right.
A strange submarine was moving slowly toward them!