"You can mold us a pair of new face masks—big enough to cover the earphones," Tom suggested. He handed Bud a penciled sketch from the workbench, adding, "Then drill the holes for the mikes and earphones—the dimensions are there on the drawing. But watch it so you don't crack the plastic."
While Bud complied, Tom began assembling the tiny electronic parts. In two hours the gear was ready for testing.
Tom wiped his perspiring forehead and gave Bud a grin of satisfaction. "Go get your swim trunks, fly boy. Let's give it a tryout in the tank."
"Swell idea! Be back in a jiff!"
After a quick change, the boys strapped on the new hydrolung equipment. Before adjusting his face mask, Tom mentioned that he had inserted scrambling circuits into the communicators to foil any enemy eavesdroppers.
"If they do pick up anything, it'll sound like chop suey," Tom ended with a chuckle.
The boys submerged in the test tank and proceeded to give the new underwater communication system a thorough check-out. It worked perfectly. Ten minutes later Tom and Bud clambered out again, dripping wet but well satisfied.
They had just peeled off their masks when Chow came charging into the lab, with a crowd of workmen and technicians at his heels. The cook was wild-eyed with panic.
"What's wrong, Chow?" Tom asked in alarm.