The stern of the Alerte was beginning to be visible as the vessel backed. If she carried sternway much farther, the fragments of the boat with the two fugitives clinging to it would be exposed to the view of the pirate crew.
More and more of the after-part of the pirate submarine's hull showed until the end of the mainmast derricks came into view. Then, at first almost imperceptibly, the sternway movement diminished. A smother of oily foam from the Alerte's twin propellers was flung astern. Her engines were going ahead. For a brief instant the relative position of the pirate craft and her prize remained unchanged; then, gathering way, the Alerte forged ahead and disappeared from the view of the two chums.
"Think she'll be put about if we're missed?" asked Vyse anxiously.
"Might," admitted Broadmayne. "Perhaps they're so taken up with their success that they've forgotten all about us. 'T any rate, up we go. We'll lie doggo as long as we possibly can, in case Cain has a fancy to renew our acquaintance."
It was no easy matter to swarm up that fifteen feet or so of trebled, twisted rope. Their hands, smothered in thick oil, had great difficulty to obtain a steady grip, while, to make matters worse, the tanker was again rolling badly. With every roll the falls with their human burdens bumped heavily against the ship's side.
At last the Sub reached the stanchion-rail. Crouching, he edged sideways to enable his companion to gain a place of safety. Then he gave a quick glance along the tanker's deck.
It was deserted. The two engineers, having completed their forced task of casting off the Alerte's warps, had gone below to obtain tools to effect the release of the rest of the crew, who, knowing that the pirate had sheered off, were clamouring loudly for help. Doubtless they were under the mistaken though by no means unfounded idea that their vessel was being scuttled, and that they were in peril of being drowned like rats in a trap.
Broadmayne's next thought was for the Alerte. A roll of the tanker raised the side sufficiently to enable the Sub to see right across her deck to the expanse of sea beyond. There was the pirate submarine, stern-on, legging it as hard as she could go in a northerly direction. Already she was between a mile and a half and two miles away and momentarily increasing the distance at the rate of a mile every four minutes.
"All clear," reported the Sub. "Keep down as much as you can in case Cain and Co. are using their binoculars. Now then, we've got to find a place to stow ourselves."
"Not in these trousers," rejoined his chum. "We're shedding a trail of oil. Deck isn't any too clean, I admit, but look there! A wash and brush up and a change of clothing is what we want."