It was agreed that Jenkins would make a sweep by one side of the ship, then trawl for a couple of miles before turning back and returning on the other side. That gave them an hour to get on board the ship and back. They would keep in touch with Jenkins using their underwater communicators to talk to a hydrophone Trout had hung into the water before they went over the side.

They swam deeper, moving their legs in a steady flutter that ate up the distance. They could hear the muffled grumble of the fishing boat engine as Jenkins got under way again and dove to thirty-five feet, where the visibility was still fair.

With powerful scissors kicks, they covered the distance to the ship in a short time.

The gigantic hull emerged from the murk like the body of an enormous whale asleep on the surface. Austin signaled Trout to go deeper. When they were directly under the massive keel, they looked up and snapped their lights on. It was hard not to be unnerved by thousands of tons of black steel floating above their heads.

“Now I know how a bug feels just before someone steps on it,” Trout said, gazing up at the massive hulk.

“I was thinking the same thing, but I didn't want to make you nervous.”

“Too late. Where do you want to start?”

“If I interpreted the satellite photos correctly, we should find what we're looking for at midships.”

They swam slowly upward until the ship's barnacle-encrusted bottom entirely filled the lenses of their face masks. In the beam of his light, Austin saw what he was looking for, a rubber-edged seam that ran across from one side of the flat-bottomed hull to the other. “Bingo!” he said.

When Austin had first looked at the satellite pictures, he'd noticed an open area around one of the derricks that rose from the deck. Someone had carelessly left off a tarp that covered the opening and he could see down into a black void. He was sure he was looking into a “moon pool,” a docking space similar to that on the Argo and other NUMA ships.

Austin knew from experience that odds favored the pool's gates being closed. It was standard operating procedure, otherwise the drag from the open sea would slow the ship down. But he remembered that some NUMA ships had a smaller pool used for launching ROVs. He saw what he was looking for on the port side, forward of the larger moon pool, an indented rectangle about twelve feet square. When they swam close, they saw that the gates of the ROV launch well were shut tight.