Read Online Undetected by Dee Henderson - Free Book Online

necessary is exponentially higher than a cross-sonar search, a fact that risks someone being able to gather enough data to crack the algorithm behind cross-sonar itself.
    â€œAnd operationally it will only be helpful at the margins. The odds that two U.S. subs, with towed arrays deployed, running cross-sonar, miss hearing an enemy sub are very small. Their noise profile is too high. But an active ping should give you added range so you can pick them up at a farther distance than what cross-sonar on its own can give you.”
    Bishop appreciated the limitations, but he already saw one key use. “An active ping would solve the problem of a sub lying in wait, with its engines and propulsion powered down, drifting and waiting for someone to come across his path. Right now we have to trust luck—someone on board drops a wrench, or closes a hatch too loudly, or the natural drift requires them to engage the drive shaft every few hours to keep from settling too deep. But the new electric-diesel combination subs can rest on the ocean bottom on the continental shelf, down around 400 to 500 feet, and are difficult to locate until they lift off the ocean floor. An active ping that couldn’t be traced to its originating location would be a significant help in finding them.”
    She nodded and slid the lid back onto her ice cream. “There isn’t enough data in this British sub encounter to give me more than a probability that this works. It looks promising, but I don’t know if it’s more than that.”
    â€œWhat do you need?”
    â€œA couple more weeks and I’m going to be at the endof what I can do with the existing data. I need a sea trial to test the idea. And that’s going to be a problem. It can’t be run at Dabob Bay. It’s going to take ocean time. I need two fast-attacks and a boomer, although I might be able to give an answer with three fast-attacks. I need the right mix of sea conditions, with a choreographed set of maneuvers to create the permutations in data I need to see. There will be a massive amount of data to record. And if I’m wrong, that sea trial risks giving away cross-sonar to anyone within listening range.”
    â€œYou lay out the probability it works, you’ll get your sea trial to gather data,” he predicted.
    â€œI hope so.” She started to say something, stopped, appeared to change her mind, and simply said, “I don’t expect this idea to hold up, Mark. But it’s probably going to take that sea trial to put my finger on where it falls apart. I think it may prove fragile, only working a portion of the time based on the sea conditions. It seems extra sensitive to white noise, which is what I’m trying to test for now with the existing data. Nothing would be worse than running a test that tells you all is clear, only to find it didn’t see an enemy sub sitting nearby.”
    â€œAll of a submariner’s life is probabilities, Gina. If this could find a quiet sub that other techniques miss—even if it could do it in only one out of five times it was tried—it would still save lives. Whether the risk to cross-sonar being reverse-engineered is worth it depends on the variations where this proves helpful and the time it takes to execute the ping.”
    She nodded. “Anyway, that’s what I’m working on.”
    â€œI appreciate you telling me, trusting me.” They had started walking again, and he closed up his own ice cream. “Earlier, you said ideas, plural. What else are you exploring?”
    â€œI’d rather not say until I know if it is even feasible. I’m still looking for a data set that will let me explore the idea. It’s . . . well, it’s kind of out there, even for me,” she admitted.
    â€œThis idea was kind of out there too,” he remarked. “Let me know if you need some help finding that second data set. I’ll see if I can get you what