suitcase. Although the ROV was relatively small, it carried video and digital cameras and a manipulator arm.
Moving the joystick with a skilled hand, Gunn angled the ROV into a long dive. The vehicle used the navigational net established for the UUV to find its way directly to the target. Color faded from the water, as each descending fathom took the ROV farther from the dappled surface light. Gunn switched on the twin 150-watt quartz halogen lights, but even their powerful beams were swallowed by the thickening gloom.
The ROV smoothly descended to three hundred feet, then leveled out a few yards above the ocean floor. The vehicle bucked a slight bottom current that kept its speed under a knot as it moved forward above the black mud. Then the bottom dropped away and the ROV soared over the lip of the undersea canyon so suddenly that everyone in the room felt a slight wave of queasiness. Gunn nosed the ROV downward, keeping the vehicle parallel to the sharp slope.
The ROV's side-scan sonar painted the target on a separate monitor until it was close enough for visual inspection. Gunn goosed the vertical thrusters, and the vehicle rose slowly above the vessel.
The ship lay at an angle on the sloping side of the canyon, the bottom section of hull embedded in mud. The ROV descended several yards and moved alongside the hulk at main-deck level, past a row of portholes, including some that were still open. Barnacles covered most of the ship and heightened its spectral aspect. Reddish patches of antifouling paint peeked out here and there. The wooden wheelhouse had disintegrated and the decks had rotted away. The lifeboat davits were empty, and wire shrouds hung with seaweed. A pile of rusty debris was all that remained of the collapsed funnel.
The ship was a metal cadaver, useless except for the schools of fish that nosed through passageways where humans had once walked. To Austin, who watched the screen with an expression of fascination on his bronzed features, this sad and lifeless hunk of rusty metal was a living thing. Although there were no hands to close the hatches forced open by the pressure of escaping air, Austin could almost hear the creak of the booms and the throbbing engine as the ship plowed through the seas. In his mind's eye, he pictured the helmsman standing with feet braced on a wooden grating, hands on the wheel while crewmen went about their business on deck or fought the inevitable boredom of shipboard life.
Austin asked Gunn to steer the ROV around to the stem. As Ensign Kreisman described it, the hull was covered with growth that hid the ship's markings. Gunn poked the vehicle into several nooks and crannies, hoping to come across a manufacturer's metal plate, but they found nothing.
Austin turned to Gamay. 'What's our resident nautical archaeologist have to say about this old gal?'
Gamay pinched her chin in thought as she stared at the ghostly images on the glowing screen.
'My specialty was Greek and Roman wooden ships, and if you asked me to ID a bireme or a trireme I might be of more help. I'll venture a few guesses, though.' The camera was moving along the midships section, where the rusty steel plating had buckled and was clear of barnacles. 'Those are riveted steel plates. By the 1940s, shipbuilders had switched to welding. The booms indicate that she's probably a cargo ship. She's an old-timer, judging from her lines, maybe built in the late eighteen-hundreds or around the turn of the century.'
Austin asked Gunn to move the ROV around to the damaged side. The ship leaned downhill, and from this angle it looked as if it could come crashing over at any second. Gunn brought the ROV straight in until the hole filled almost the entire screen. The lights probing the ship's innards picked out twisted pipes and steel columns.
'Damage assessment, Rudi?' Austin said.
'From the way those edges are curled, I'd say a projectile hit the engine room. Too high for a torpedo. Probably a shell from a big gun.'
'Who would sink a harmless old freighter?' Zavala asked.
'Maybe someone who thought she wasn't so harmless,' Austin said. 'Let's check out the cabin section that Ensign Kreisman told us about.'
Gunn tweaked the controls, and the ROV rose abovedecks. It was clear from the grin on his face that Rudi was having a ball. He brought the vehicle around, taking care not to catch the tether in the foremast or booms. The ROV moved past the bridge, then stopped and hovered in front of a dark rectangular opening. Unlike the ragged cavity in the hull, the edges of the hole were relatively even from the cutting torch. Gunn brought the ROV to within a few feet of the opening. The lights picked out the framework of a bunk and the remnants of a metal chair and desk that lay in a tumbled heap.
'Can we go inside?' Austin asked.
'I'm getting a side current that could make things tricky, but I'll see what I can do.' Gunn maneuvered the vehicle left and right, then when it was directly centered, he put it through the hole as easily as a seamstress threading a needIe. The ROV was capable of turning within its own radius, and Gunn executed a three-hundred- sixty-degree turn. The camera captured slimy gray piles of debris. Gunn probed a corner with the ROV's manipulator, stirring up a powdery cloud of rust. Then the ROV got tangled and wouldn't, move. Gunn waited for the dust to settle and wriggled the ROV until it broke free of the overhead wire that had snagged a projection of its protective shielding.
'What do you think?' Gunn said, turning to Austin.
'I think anything of value has been removed. We'll have to piece together the story from the ship itself, not what's in it.' He pointed to a wall shelf. 'What's that?'
Austin's sharp eye had caught a dark, squarish object. Gunn used the manipulator to clear away a pile of amorphous grayish-brown trash and made several fruitless attempts to grab the object. It kept slipping away like a prize in a penny-arcade game. Gunn set his jaw in determination and pushed the object into a corner where he could get a firm grasp on it, then he backed the ROV out of the cabin and moved the manipulator to put the prize directly in front of the lights. The claw clutched a small, flat box.
'I'm bringing her up,' he said. He reversed the ROV's direction and sent the vehicle scuttling back to the Argo. Minutes later, the lights of the moon pool appeared on the screen. The captain ordered the ROV's handlers to stabilize the artifact in seawater and send it to the vehicle control room. Soon a technician arrived, carrying a white plastic bucket. Gamay, whose background in nautical archaeology made her the most experienced conservator on board, asked for a soft brush. She removed the box from the bucket and gently placed it on the floor. Then, with soft strokes, she brushed a thumbnail patch of the black patina to reveal the gleam of metal.
'It's made of silver,' she said, and continued to work until fifty percent of the top was cleaned. The metal was embossed with a double-headed eagle. Gamay examined the clasp. 'I might be able to get this open, but I don't dare because I could destroy what's inside when it hits air. It may need intense conservation.' She glanced at the captain.
'The Argo is primarily set up for biological and geological survey,' Atwood said. 'There's another NUMA ship called the Sea Hunter doing archaeological work not far from here. They might be able to help.'
'I'm sure they can. I did some research on the Sea Hunter a couple of years ago,' Austin said. 'She's the sister ship of the Argo, isn't she?'
'That's right. The two vessels are almost identical.'
'We should get this box there soon,' Gamay said. 'I'll stabilize it in seawater as best I can.' She glanced with longing at the box. 'Damn! Now I'm really curious about the contents.'
'How about running it through the X-ray machine in the infirmary?' Austin suggested. 'That might partially satisfy your curiosity.'
Gamay carefully replaced the box in the bucket, and the technician carried it off. 'You're brilliant,' she said.
'You may not think so after you hear my next idea,' Austin replied. He outlined his plan.
'Worth a try,' Atwood said, and clicked on his hand radio. Before long the screen flickered into life and the moon pool appeared again. The ROV was being put back into the water. The dive was a repeat of the first, with the diver, bubbling foam and dark water.
Gunn put the ROV on a direct trajectory to the wreck. Before long, the vehicle was coming from behind the ship. Gunn worked the joystick, and the mechanical arm unfolded and extended to where it could clearly be seen in the glare of the halogen lights. Watching Gamay clean the artifact had given Austin the idea. Clasped in the metal claw was a metal-bristled brush used in preparing the Argo's hull for painting.
The ROV made several attempts to clear away the barnacles. Newton's law of action-causing-reaction kicked in, and the brushing pushed the ROV away from the hull. The ship did not want to give up its identity without a fight. After forty-five minutes, they had succeeded in clearing away a patch about a foot in diameter. A portion of a letter embossed in white was visible. It could have been an O or any of several other letters.
