"We've got 'em!" roared Bobby, above the throb of the pistons.
He spun over the wheel, and, swinging round like a greyhound on the trail, we leaped seaward straight for our helpless prey.
I found Campbell standing beside me, a revolver gripped in his hand.
"If there's any sign of trouble," he said quietly, "shoot at once. You keep your eye on Craill and I'll look after Manning."
I had rather it had been the other way on, but there was no time for arguing.
Even as he spoke I saw Manning fling down his useless spanner, and, wiping his hands coolly with a piece of cotton waste, step up into the stern. Craill followed, his evil, scowling face in strange contrast to the smiling calm of the other.
Slackening speed at just the right moment, Bobby brought us alongside with masterly precision.
Campbell leaned forward, his eyes fixed grimly on the pair of them.
"It's no use, doctor," he said, "your luck's out this time."
With a ghastly sound, half-way between a sob and a scream, the gaunt figure of de Roda rose suddenly from the deck. A torrent of Spanish curses burst from his throat, and, dropping the bag of diamonds which he was still holding, he staggered to the side, shaking his fists at us in a frenzy of maniacal rage.