The sky lightened and a few minutes later the tense group on the deck of the _S-18_ made out the outlines of the ship which was beyond the reefs. It was the _Iron Mate_, rolling gently in the swell. Through field glasses they could see men clustered along the rail of the tramp steamer and Tim thought he could see Sladek on the bridge. The first move was up to the _Iron Mate_ and it was not long in coming. From the far side of the steamer came the roar of an airplane engine and the seaplane took wing, its colors flashing in the bright rays of the sun. "Better get ashore at once and have your own plane ready to take off," Commander Ford advised Tim. "Take Pat with you and be sure that you have a light machine gun." Pat got the gun and plenty of ammunition from Joe Gartner and they tumbled into one of the small boats and started for shore. Out to sea the other plane was climbing rapidly, circling over the _Iron Mate_. It was up 2,000 feet by the time Tim and Pat reached the Sea King and had torn off the motor coverings and loosened the moorings. Tim piled into the after cockpit and snapped on the starter. The motor awoke with a roar and he warmed it up thoroughly, keeping an eye on the plane above. There was little wind and he could take off in a straight dash across the water. Pat, the light machine gun in his arms, climbed into the forward cockpit. There were parachutes for both pilot and passenger and Tim instructed his companion in the operation of the chute. "If we go aloft I'll get even with you for some of the unhappy hours I've spent in that tin fish," chuckled Tim. Pat, a little white around the lips at the thought of his first trip aloft, grinned gamely. "I can take it," he said. The plane from the _Iron Mate_ was darting toward the Isle of the Singing Trees. The ship was coming down now in a terrific power dive. Tim estimated the speed at nearly 150 miles an hour. The air was filled with the roar of the motor. Then the oncoming plane levelled off and flashed over the _S-18_. Something black hurtled over the side. Tim tried to shout, but his throat closed and he could only gasp. Automatically he leaped into action, his hand jamming the throttle on full. The Sea King scuttled across the water, angling away from the _S-18_ while down from the sky plummeted the black object. It struck the water a good hundred yards away from the _S-18_ and a fountain of water arose in the air. The noise of the bomb could be heard even above the roar of the Sea King's powerful motor. Tim lifted the finely trimmed craft into the air and set out in pursuit of the bomber. Below them on deck of the _S-18_ Gunner Joe was training his sights on the _Iron Mate_. Tim, looking down, saw a puff of smoke and a fountain of water leap into the air beyond the _Iron Mate_. Joe had overshot his target.