Then an unexpected manoeuvre took place. The men in the boats, fully prepared to have a terrific dusting from the swell of the swiftly-moving destroyers, had resumed their oars and were heading so as to meet the curling bow waves end on. Instead of holding on their course, which would have taken them not less than half a mile from the nearest boat, the destroyers altered helm, one passing on either side of the little flotilla. Losing way under the reverse action of their quadruple propellers, the destroyers came to a standstill. "On board, every mother's son of you!" shouted an officer from the bridge of the _Messines_. The survivors of the _Complex_ could hardly realize their good fortune. They were to be in at the death after all. They were to witness, and perhaps take an active part in, the smashing up of the so-called _Holton Heath_, otherwise the Rioguayan light cruiser _Cerro Algarrobo_. Quickly the work of taking off the boats' crews was accomplished, the majority finding a temporary home on board the _Armentières_, the rest on the _Messines_. Sub-lieutenant Cavendish was amongst the latter. He had barely time to exchange greetings with a short, bull-necked brother-officer--one Slade, who was on the same term with him at Dartmouth--when the _Messines_ forged ahead again, leaving three deserted boats bobbing forlornly in her foaming wake. "How goes it, old thing?" inquired Cavendish. "Not so dusty," admitted Sub-lieutenant Slade. "We're hoping to finish the job before dark. We've a couple of hours yet.... You've been having a bit of a jamboree, eh what? See anything of the submarine?" "I did," replied Cavendish grimly. "Both ends with nothing between 'em." "Are you trying to pull my leg, Weeds?" inquired Slade earnestly. "No--fact," was the reply. "We did her in with an ash-can--a couple, in point of fact. Couldn't let you know before. Dynamos were flooded and emergency wireless was out of action." "You must tell our owner that," continued Slade. "He's on the bridge." Lieutenant-Commander Trehallow received the information with marked enthusiasm and not a little relief. Hitherto, he was hampered by the knowledge that there was a mysterious submarine acting as consort to the pirate surface-craft. The submarine accounted for, left him and his "opposite number" on the _Armentières_ with relatively free hands. They could concentrate all their energies upon the pursuit of the _soi-disant Holton Heath_ without the chance of becoming targets to an invisible foe--unless there were other submarines out.