“I suspect they will try to do something to delay us,” the lieutenant said. “They may drop something in the channel, for there is one place where it is very narrow and quite shallow, and almost any large object—an anchor, sticking up on the coral, would crush our bow planks at the speed we’re making.”

Brownie kept a sharp watch, and soon discovered, as they approached the narrowest and shallower part of the channel, something dark on the bottom.

“Cliff and Jack and the colored men will stop them I hope,” said the commander as they slowed and drew near to the submerged danger.

“They will, if they can do it,” Brownie said. He dropped over the bow and discovered that his commander had foreseen exactly what had been done; the Libertad’s anchor had been cut loose, and, with some spare engine parts, had been flung from the white boat’s stern into the channel with the hope that the cutter would run onto them and be entirely disabled, before they were noticed.

While the damage was averted, it took time to lift the heavy metal under the water, and to displace it.

Meanwhile Cliff sat on the slanting deck of the Senorita, with Jack and Sam, while Jim hung close above them on the top of the cabin, his eyes fixed on the distances of the channel.

“What will you do if they come in daylight?” Cliff looked up at him to ask.

“Shoot at the waterline and let the water in,” said Jack.

“But they’ll shoot back,” objected Cliff.

“That’s the chance we have to take,” Jack answered.