"Commodore?" Claggett asked, and got a nod. "There was an Akula-class out there somewhere. The P-3S lost him south of Kodiak, so he was within maybe six hundred miles of us. That doesn't mean this is him."

"Which one?"

"Admiral Lunin." Claggett answered.

"Captain Dubinin?"

"Jesus, you are cleared pretty good," Mancuso noted. "They say he's very good."

"Ought to be, we have a mutual friend. Is Commander Claggett cleared for that?"

"No. Sorry, Dutch, but that is really black."

"He ought to be cleared for that," Jones said. "This secrecy crap goes way too far, Bart."

"Rules are rules."

"Yeah, sure. Anyway, this is the one that twigged me. Last page." Ron flipped through to the end. "You were coming up to antenna depth "

"Yeah, practice on the missiles."

"You made some hull noises."

"We came up fast, and the hull's made of steel, not elastic," Claggett said in some annoyance. "So?"

"So, your hull went up through the layer faster than your "tail" did. Your towed array caught this."

Claggett and Mancuso both went very quiet. What they saw was a fuzzy vertical line, but the line was in a frequency range that denoted a Soviet submarine's acoustical signature. It was by no means conclusive evidence, but it, like all the other things Jones had notated, was dead aft of Maine’s course.

"Now, if I was a betting man, which I'm not, of course, I'd give you two-to-one that while you were underneath the layer, someone might have been tooling along just over top, letting his tail hang under it. He caught your hull transient, saw you were going shallow, and ducked under the layer just as you came over it. Cute move, but your big up-angle meant that your tail stayed down longer than it should have, and that's where this signature came from."

"But there's nothing after that."

"Nothing at all," Jones admitted. "It never came back. From there on to the end of the tapes, nothing but random noise and otherwise-identified contacts."

"It's pretty thin, Ron," Mancuso said, standing up to straighten his back.

"I know. That's why I flew out. In writing it would never sell."

"What do you know about Russian sonar that we don't?"

"Getting better approaching where we were, oh, ten or twelve years ago. They pay more attention to broad-band than we do - that's changing now. I sold the Pentagon on taking another look at the broad-band integration system Texas Instruments have been working on. Commander, what you said before about being a black hole. It cuts both ways. You can't see a black hole, but you can detect it. What if you track an Ohio by what should be there but isn't?"

"Background noise?"

"Yep." Jones nodded. "You make a hole in it. You make a black spot where there's no noise. If he can really isolate a line of bearing on his gear, and if he's got really good filters, and one dynamite sonar operator, I think it's possible - if something else cues you in."