Jim Durham - F.O.D. [novelette]

Electronic recording systems produce data. It takes a human mind to turn data into information.

The visiphone chimed once, softly, then said, "Colonel Wall calling, sir." David Regis dropped Wild West into a drawer, picked up last month's Undersea Technology, and said, "It's Woell, Sandra. Wo-ell, not Wall. Put him on."

"Yes, sir. Colonel Wall," corrected the phone. The calm, dark features of J. Patterson Woell formed on the screen. "Hello, Regis. Why can't your phone pronounce my name?"

"Morning, Colonel," returned David. "Her discrimination circuits don't believe you." He patted the phone's memory unit. "Sandra thinks you don't know how to pronounce it."

"We built that model, didn't we?" said the colonel. David nodded. "Probably a stray piece of wire in there." David Regis, head of Quality Control of Transport Systems (Marine Division), winced.

"That was pretty pointed," he said. "Have we lost another one?"

The image in the phone clenched its jaws. "Yes," it answered. "The Cousteau. She was due this morning in Galveston, and a Navy plane heard her damage beacon not an hour ago. The Cruise Data Recorder was floating over the Puerto Rico Trench. I have already sent the Cavalry, with D.S.R.V.'s and bloodhounds. A Navy D.S.R.V. will be airdropped within the hour. Regis, if this turns out to be another Foreign Object case ..."

David Regis slumped in his chair, hands over his eyes, shaking his head slowly. He looked up at the implied threat, his face almost blank, and stared at the man on the screen.

"I'm sorry, David," said Colonel Woell after a moment. "Captain Wilkins was a friend of yours, wasn't he?"

"That's right." Abruptly David turned away from the screen and gazed out his window at the sea above him.

"I'll tell Jennie," he muttered.

"What?" asked the image.

"I'll tell his wife," David repeated. He turned back to face the phone. "Let me know when it's certain, and I'll tell her."

"All right. And I'll want the Cause of Damage Report as soon as possible. Senator Willis will be on my neck again, as soon as he hears about this." The visiphone screen went blank.

David Regis turned back to the window. It was set directly into the pressure dome, seventy feet above the seabed level, and twenty feet above the great, steeply sloping skirt of plastic that sealed the city against the ocean. Although the dome was fifteen feet thick, a highly efficient plug of fiber optics transmitted the scene outside the window so faithfully that only inches appeared to separate the ocean and the man. The water was greenish, fading abruptly to a thick, impenetrable black that seemed to resent the city's lighted presence.

David could see a line of beacons, their beams slanted away from the city of Velikovsky, two miles deep in the, Antarctic Ocean. A tiny two-man prospecting sub moved rapidly out along the line on its way to a claim area. It seemed an impossibly frail thing to be challenging the blackness.

As he watched, a viperfish drifted past his window, the feeble glow from its row of body lights washed out by the city's luminance. Its stomach was distended by another fish whose tail still feebly flapped from the viper's jaws. David shook himself, and turned back to the desk.

"Sandra, show me the Cause of Damage files on the Scott Carpenter, the SeaStar and the Woods Hole," he said. "Put them on the desk screen."

"Yes, sir," said the phone, and the top of the desk, which was tilted toward him like a drafting table, displayed three file covers.

David Regis touched a contact at the desk's edge, and the covers were replaced by print. He began reading. Now and then he circled statements with a light-pen, touched a contact marked "Correlation" on his desk top, and watched the circled statements appear together on a fourth page.

After a while, he yawned and rubbed his eyes. "O.K., Sandra, that's it for today," he said. "File it, and give me a print of the correlations."

"Yes, sir," murmured the phone, as several sheets of paper emerged from a slot below the screen. David Regis picked up the papers, slipped them into a folder, and put the folder into a dull green briefcase.

"Good night, Sandra." He walked out the door. "Lock it up."

"Yes, sir. Good night, sir," responded the phone. The door closed and the lights turned themselves slowly out behind him.

Later in the evening, David found himself standing at a door across the Dome from his office, holding a bottle of peach brandy in one hand and a spray of violets in the other. He touched the contact patch with his elbow and waited.

The door was opened by a girl whose vivid red hair was accentuated by the milk-and-cherries whiteness of her skin. Peggy Hanson's skin was touched only infrequently by the sun, and then only through a thick layer of ultraviolet-reflecting creams. The "untanned" look currently in vogue among the topside women was easy for Peggy, and superb on her as well. "Come in, David," she said. "You're late, and supper will suffer for it."

"I'm sorry, Peg," he said, "but - "

"No, no," she interrupted, "I know you had a good reason, and it doesn't matter anyway. No business tonight, huh?" She looked at him, and could see the tiny strain lines around his mouth. She kissed him gently. "At least wait till after supper."

"All right," he agreed. "No work until you've fed me." He handed her the small bouquet of fresh violets. She buried her face deeply in the blossoms. "Oh-h-h!" she sighed. "How can anything so tiny hold so much fragrance?" She pulled David into the kitchen, where she found a small flat vase to put the flowers in. She set the vase in the middle of the dining table. "There!" she approved. "A fitting complement to my sweet-and-sour pork - which we'd better eat now, before the rice gets clumpy."

After supper, David Regis laid out the facts on the table. "Four ships in two months! First, the SeaStar," he said, placing his iced-tea spoon in front of him. "Lost with all personnel in the Mariana Trench. No wreckage found, but Cruise Data Recorder recovered. Cause of damage, catastrophic pressure build-up in the sodium-cycle heat exchanger." He tapped the fork against the table. "Apparently, something blocked the bypass valve. The explosion could've split the hull in half."

"And Transsystems gets the blame," said the red-haired girl across the table.

"We put the ship together, Peggy. We didn't build the heat exchanger, but we put it in and charged it, and there shouldn't have been anything in there to block the valve." He leaned back in his chair and sipped his tea. "Peggy, you wouldn't believe the trouble we go to, just to make sure some clown of an assembler can't make a mistake like that. We have industrial psychologists who do nothing but design assembly and inspection techniques for Quality Control. Those guys are good, too." He shook his head.

"What plugged the valve?" asked the girl.

"We don't know for sure, but there's a certain lockbolt used in the mating assembly that fits the valve orifice perfectly. If one of those got into the exchanger tubing some way, it would have plugged the valve eventually."

"Can you be sure it won't happen again?"

"I still don't know how it could have happened the first time. The exchanger coils are checked for free flow just before assembly, and neutrafluxed afterward. But we went back and rechecked the entire heat exchanger on all of those subs. Didn't find a thing, of course."

"Then the next one didn't have the same kind of failure?"

"No," said David, reaching for a knife. "The Carpenter," he said, placing it alongside the fork. "This was one of the first cargo subs built. She had logged better than a million and a half miles, and you'd think any built-in trouble would show up in that time. We picked up the Cruise Data Recorder about eight hundred miles south of the Aleutians, but never found the ship."

"Don't the ships carry some sort of beacon?"

"Yes, but it's only useful for ranges less than ten miles or so, underwater. Even then, the transponder could be buried in the mud. You almost have to know where the wreck is, first." He pursed his lips. "We'd never know which ocean the ship was in if the Cruise Data Recorder didn't detach itself and float to the surface."

"What happened to the Carpenter?"

"Electrical failure of some kind," David answered. "The C.D.R. recorded a massive overload in the Central Blanking Unit. Signals intended for some systems were received and acted on by other systems. Apparently it went crazy and dived into the bottom. You'd call it myasthenia gravis in a human." He sipped thoughtfully at his tea. "The only way we could simulate the failure in the lab was to toss a wrench into the works - literally! Circuits fully fifteen centimeters apart had to be shorted simultaneously."

"How could such a thing have happened?" Peggy wondered.

"Well, it wouldn't be easy," David replied. "First, the technician who performed the last check-out would have had to ignore at least five tool-handling rules just to get near the board with a loose tool of the right size. Second, he would've had to pick just the right tool - flat, no more than five inches long, with a slight bend at one end. Third, he would have had to be blind to miss the tool on his final inspection before sealing the board up."

"Could it have been intentional?" asked Peggy.

David sighed. "We narcohypnotized everyone who had access to the unit. If one of them did it, he didn't know about it. Yet ... yet the C.B.U. was shorted by something."

"The next was the Woods Hole, wasn't it?" Peggy recited the incident. "The crew's survivors sued Transsystems for, uh ... 'gross negligence in installation and design'. Something about a blocked air-supply pipe."

"That's right," said David. "The C.D.R. showed sudden lethal levels of carbon monoxide. The crew wouldn't have lasted more than two minutes. The sub finally ran aground somewhere in a deep off New Zealand, and released the C.D.R. There was some speculation that the C.D.R. may have been released before the sub finally stopped, because we never found a trace of her, either."

The girl shuddered. "How horrible! Could the crew tell what was happening?"

"Not really," said David. "They'd just suddenly be very sleepy. In fact, about a minute after the CO2 flooding began, the sub's intercom carried the captain's voice, saying, 'So sleepy!'"

"Isn't there an alarm system on the sub for things like that?"

"Yes, but apparently it didn't operate. We couldn't find any reason for that, but we did simulate the CO2 flooding by dropping a bottle cap into the air-regeneration tubing. It blocked a CO2-scrubbing loop, causing the scrubber to dump its accumulated waste into the airstream."

"A bottle cap!" echoed the girl.

"Yep. Completely, painfully typical Foreign Object Damage. That really set my neck against the chopping block. And now," he carefully picked up a knife and placed it beside the other three, "and now the Cousteau." He beat gently on the table with his fist.

"Do ... do they know about the crew yet?" asked Peggy hesitantly.

"No sign of them," replied David. "But then, there never is." Sorrow etched his face. "I had to tell the captain's widow this afternoon - that's why I was 'a little late. And I couldn't even tell her what had happened ..."

The visiphone chimed. "Your visitors are here, sir. Senator William Willis, Dr. Raymond Fisher, and Mr. Michael Roper."

"O.K., let them in, Sandra," said David, rising. He walked to the door. "Come in, gentlemen. Hello, Senator."

"Good morning, Mr. Regis," replied the senator. He was an older man, with wisps of white hair clinging to his shiny scalp. He entered the door, limping slightly, and turned to introduce his companions. "This is Dr. Fisher, our consulting physicist." The tall man with the alert, penetrating gaze shook hands with David. "And this is Mr. Roper, my staff assistant." The third man was short, with a thin mouth, cold eyes, and a limp handshake. David motioned them to chairs and returned to his desk.

"I understand from Colonel Woell that you are here on an informal fact-finding tour concerning the lost cargo subs."

"Yes," nodded Senator Willis. "We want to get to the bottom of this rash of accidents."

"There are several apparent, uh ... discrepancies in the entire picture," put in Mr. Roper. "We want clarification of these items, plus some idea of the overall probabilities involved in this type of incident." He consulted his notes for a moment. "We wonder, for instance, if your assembly and inspection methods are up to standards."

"Also, Mr. Regis," interrupted Dr. Fisher, "I'd like to know just how reliable your data-recording techniques are. The probabilities involved in the accidents seem so small as to be, well, unbelievable. I'm wondering if your recorders are presenting unambiguous fact."

"I think we can satisfy you on that point," said David. "Something certainly happened; the subs are lost, and F.O.D. appears to be the culprit in the three previous cases. We don't know about the Cousteau yet, of course."

"F.O.D.?" said Dr. Fisher.

"Foreign Object Damage," explained David. "While you're here, I want to show you the lengths to which we go to prevent this sort of thing. I think you'll agree that we have done everything possible."

"Frankly, Mr. Regis, we believe that Transsystems in general, and your Quality Control Division in particular, is guilty of gross negligence in the construction of those subs," announced the senator.

"I am aware of that, Senator, and I'm going to try to persuade you that your belief is incorrect," returned David.

The senator smiled thinly. "Certainly," he replied, "and that is precisely what Roper and Fisher are here to prevent - or rather," he amended, catching sight of Dr. Fisher's frown, "to assure that you present your case, uh, fairly. You are in trouble already, Mr. Regis, and if Quality Control is responsible for the loss of the Cousteau, we will have your hide."

David looked straight at the senator. "If Quality Control is responsible, sir, I'll give you my hide willingly." The senator looked up somewhat surprised. "One of my best friends was the captain of the Cousteau," David said, his voice flat.

The visiphone chimed almost inaudibly and a message appeared on the screen. David glanced at it, then looked at the watch on his wrist.

"The sub carrying the Cruise Data Recorder from the Cousteau just arrived, and the data will be processed in an hour or so, Senator. In the meantime, let me give you a general idea of the C.D.R. and the way we use it."

"We aren't here to be overwhelmed by technical details, Mr. Regis," said Senator Willis. "Let's not spend too much time on these things."

David suppressed an impulse to grab the old man and shake him. "As Dr. Fisher pointed out earlier, Senator, the C.D.R. is of prime importance to your investigations. The truth of a piece of data - the information content - depends entirely on the characteristics of the systems that gathered and stored the data. You have to be familiar with the C.D.R. to understand the limitations of the information it gives us."

"Limitations?" said Mr. Roper. "Are you going to tell us, sir, that the Cruise Recorder is, uh... unreliable?"

"Not at all," answered David. "I am trying to point out that there is a difference between the data provided by the C.D.R. and the inferences we make from the data. The C.D.R. tells us, for instance, that the pressure behind such-and-such valve at a particular time was, say a hundred and fifty pounds per square inch. It does not tell us that a #7 mounting screw plugged the valve and caused the line to fail."

"Quibbles," snorted the senator. "Are you trying to claim that you aren't responsible for the loss of those ships?"

David stared at the man, and a muscle jumped in his jaw.

"Senator Willis," he said quietly, "you and these other gentlemen came here to 'get the facts' behind the loss of these ships. I am doing my best to acquaint you with those facts, and to show you where fact ends and inference begins. It is an imprudent man who will jump from molecular arrangements in a crystal to public statements concerning culpability in a shipping disaster, without knowing the territory he jumps over."

"Oh, very well," said the senator, tartly brushing David's words aside. "Let's get on with it."

"Sandra, let's have the C.D.R. briefing file on the wall screen," said David. While he turned to find a pointer in his desk, a section of blackboard slid aside, the lights dimmed, and an overhead projector threw a picture of a small greenish cubic crystal on the screen.

"This is the heart of the Cruise Data Recorder," said David, "a dimensionally stable, precisely machined block of tellurium II. In its initial state, it is an amorphous, noncrystalline solid, much like glass. In this state, the tellurium atoms are not bound to particular lattice sites and are scattered at random throughout the block."

He squeezed the pointer slightly, and a new slide, showing a random arrangement of atoms, appeared on the screen. "The block will revert to a crystalline state after a period of years, if left to itself. However, we help it along by impressing a crystal state on it in a controlled fashion."

He squeezed the pointer again. "Here's a cube in the recording module. It's contacted on three mutually perpendicular faces by arrays of diode lasers, which are fired into the cube in groups of three. The interference pattern set up by the three beams arranges the atoms at the beam juncture, and promotes local crystallization. The interference pattern, which contains the information to be recorded, is 'frozen' into the cube, and may be read out later."

"Can you erase the crystals and reuse them?" asked Mr. Roper. Dr. Fisher snorted softly with amusement and was answered by a glare.

"No," replied David. "The crystals can be destroyed, of course, but not erased short of that. The cube provides a permanent, unimpeachable record."

"How about information capacity?" asked Dr. Fisher.

"We can record about a hundred billion bits of information on one of these one-centimeter cubes, with an information density about one percent of the maximum realizable density. By leaving lots of room, so to speak, around each bit of information, we obtain an excellent signal-to-noise ratio, plus room for parity checks, clock bits, and indexing." He squeezed the pointer, to display a schematic of the information flow to the cube.

"The cube records data from every major system on board. Some of the systems, such as the pile activity, are monitored constantly. Others, like the inertial compass, are time-shared on a rotating basis with ten, fifty, or a hundred other sensors. Information flow to the crystal is determined by the Central Processing Computer, which quizzes the sensors in the proper order and relays the data to the beam coder."

"How long will it take to sort through the Cousteau's data and find the cause of the accident?" asked Mr. Roper.

"About an hour," said David. He chuckled, seeing the incredulous look on the other's face. "Oh, we don't do it ourselves, Mr. Roper," he said. "A computer takes care of that for us. You see, each sensor has a profile that it can be expected to follow under normal operating conditions. These profiles, together with variances, are stored in the computer. As the record is being decoded from the crystal, sensor outputs are compared to the appropriate profile, and any significant deviation from that profile is routed to a tape. The `window', or the acceptable deviation, is set into the computer before the run, and the monitor only looks at the deviations on the tape."

He paused for a moment, studying the picture on the screen. "Let me make one point clear now," he said. "You spoke of finding the cause, Mr. Roper. But we don't really find causes. We get readouts from all these sensors, and store them. We know the pile neutron flux or the sodium temperature as functions of time - we know values. But we can only guess what caused the parameters to reach these values.

"After we make our guesses, we go down to the lab and try to reproduce the sensor data by artificially inducing malfunctions. If we manage to reproduce the sensor data, we can be pretty sure of our guesses. But we never know for sure."

"So, Mr. Regis," drawled Senator Willis. "So how accurate were your guesses with SeaStar and the others?"

David Regis shook his head slowly. "Quite accurate, I'm afraid," he admitted. "Very accurate."

"I thought so," said the senator. "Well, Regis, let's have some coffee before continuing."

When the phone chimed quietly and announced, "Lester Mattingly, sir," David Regis set down the coffee cup he was warming in his hands. "Hm-m-m. This must be it. Put him on, Sandra."

Les Mattingly's faintly worried face appeared on the screen. "The tapes are ready for you, Mr. Regis."

"Thanks, Les," said David. "What did you put in?"

"Everything except the spec changes at the first of the tape. I had the normal profiles windowed at the two-sigma point, then labeled and superimposed on the deviations. Uh..." he hesitated for a moment.

"Well?" said David.

"Well, there's also a voice transmission - the captain. It's ... not too much fun. But it pretty well ties the whole situation down, Mr. Regis." David closed his eyes.

"Let's hear it, Regis," said the senator.

David took a deep breath. "O.K., Les," he nodded, "put the voice record on first, then we'll look at the sensors."

"Right." Les moved off-screen for a few seconds, then reappeared. "O.K., it's in Memory that way. Ask your display for temporary Tape A. And I'll be here if there's anything else."

"Thanks," acknowledged David. "Sandra, give me temporary Tape A."

"Yes, sir," murmured the phone. There was a moment's silence, then a woman's sultry voice filled the room.

"Attitude, attitude, att - " it said, then cut off as if switched.

"Nice warning beacon," nodded Dr. Fisher appreciatively.

A man's voice replaced it. "Captain!" it said excitedly. "We are stem-low and losing equilibrium. Pitch rate one degree per second, increasing. Fault board shows an open dive-tank valve."

A new voice broke in. "Override, Clark. Close it manually." David recognized Captain Wilkins' voice. "All ahead seventy percent, Mike. Dive vanes down."

"Down, sir?" came a surprised voice.

"Yes, dammit, down! We've got to get her stern up."

"Manual override cycled, sir. No luck - valve still open."

"O.K., what's our pitch rate now?"

"Two degrees per second, increasing."

"All ahead full, Mike. Start flooding bow tanks, blow stern tanks!" The hum increased to a discordant buzz.

"Rate slowing, sir. Pitch - minus four degrees." An audible shudder through the ship tensed the four attentive listeners. A siren began screaming somewhere.

David Regis sat stiffly upright, eyes closed and knuckles clenched white. The others hunched forward intently.

"Pitch rate increasing again! Minus five degrees! Minus seven degrees!"

"Emergency maximum power, Mike! Yank the dampers out!"

"Maximum, sir. She's heating up."

The hum climbed to a driving whine that set David's teeth on edge.

"Minus ten degrees, sir! We're losing her!" A crash sounded, with breaking glass and a curse.

"Heat exchanger redline, sir!"

"Keep her there, Mike!" came the captain's voice. "Clark, cut the power to the valve, then turn it on and override. It's got to close!"

A frown creased David Regis' face, and he leaned forward.

Another siren began its wail. "Cargo shifting, sir!" came a voice. "Dump!" shouted Captain Wilkins. "Get rid of it!" The sub rocked to a dull explosion that ripped the cargo bay lengthwise, spilling ten million dollars' worth of high-grade rubidium and yttrium into the ocean. "Still slipping, Captain! Minus twelve degrees."

"More power, Mike!"

"That's all there is, Captain. The exchanger can't take it much longer!"

Warning shouts, screams, a curse fringed the thunder of another crash. "What happened!"

"Twisting," said the captain's muffled voice. "She'll spin, break up ... Jennie!" White noise, intense, enveloping, blotted out the voices, then nothing.

David Regis leaned back in his chair, with a puzzled look.

"Horrible!" muttered Mr. Roper, with a shudder. He ran his fingers through his hair. "What was that noise at the end?"

"Huh? Oh ... the, uh, sound of water coming in, I guess."

"Water coming in? But how... ?"

"Hard to say," replied David absently. "Could be any of several things - the hull snagging on a spur of rock, for instance." He snorted with perplexity. "Sandra, get me the Sound Lab."

The phone's screen cleared, showing a youngish woman in a lab smock, sitting before a rack full of test equipment. She was looking up into a visiphone mounted high on the wall. "Sound Lab," she said. "Oh, hello, Mr. Regis."

"Hello, Sharon. Look, I want a complete V.P.A. on the voice record off the Cousteau. Use temporary Tape A for the first pass, and get the rest from Lester Mattingly, if you need it. I'll want I.D. verification and probable emotional content."

"O.K.," nodded the woman. "I take it you want the results yesterday."

"Right!" David nodded. "Let me know as soon as you've finished." He turned away from the screen just as Senator Willis rose from his chair.

"Regis," he rumbled, "I think you owe us an explanation. Are you trying to make us believe that what we just heard isn't true? What grounds have you for all of this?"

David sat down in his chair and tapped the arm speculatively. "Senator," he mused, "didn't you notice the voices on that tape seemed ... well, too calm for the situation? They shouted, they were loud, but there was very little panic in the voices. It just didn't sound right."

"Really?" Roper's voice carried overtones of irritation and disbelief. "Are you sure you aren't... imagining things?"

David stared at him, through him. "Jennie is Captain Wilkins' wife," he said softly. "Everyone calls her that."

"So?" said Mr. Roper. David's eyes focused on him.

"Ed Wilkins never called her anything but Ginger."

David Regis sat uncomfortably in a chair that had folded out of a wall of the cargo sub Cetacean, and gazed at the array of displays before him, wondering that the man behind the control consoles was able to make anything out of the crawling mass of information. Captain Ahrens caught his expression and chuckled.

"The trick is to not look at all of it," he said, "only what you're interested in."

"Don't you need all of it?" asked David.

"Well, not all at once," replied Captain Ahrens. "Matter of fact, the forward sonar view is all we need most of the time. Steering, you know. The rest of the stuff is mostly to keep us happy."

"Oh?" David raised a quizzical eyebrow.

"Uh-huh," returned the Captain, pausing to touch a key or two on his console. He studied the results in one of the displays, made a correction, leaned back. "Actually," he continued, "most of those displays are primarily for trouble indications. But since there's very little of that, most of 'em would be blank most of the time. So other data is displayed. Thrust efficiency, ship depth, floor depth, water temperature, and so on. Information we don't use, generally."

"Why display it at all?" asked David.

"Two reasons," answered the captain. "First, the systems psychologists say that we - the operations crew, that is - are happier if we feel in touch with the ship. Or in control of the ship, perhaps. Second, after a while in a given sub, you tend to become attuned to - well, rightness.

Sometimes the crew can sense problems before the central computer recognizes that the problem exists. So data isn't really useless."

"But isn't it distracting?" asked David.

"Not at all. You simply don't consciously notice anything but what you're looking at."

"Hm-m-m!" said David. He tried concentrating on one display, and was surprised to find it fairly easy to ignore the rest.

Captain Ahrens took a sip from the steaming cup on his console.

"Now," he said, turning to David, "suppose you fill me in on what this little pleasure cruise is all about."

David smiled. "1 was just about to do that," he said. "Captain Ahrens, you and the Cetacean are bait."

"I had come to that conclusion," said the captain. "But - bait for what?"

"I don't know," David admitted. "But whatever it is, it can fake inputs to the C.D.R."

"It can what?" blurted the captain.

"You heard correctly. We discovered that the voice record from the Cousteau was faked - put together from at least five separate sources, and dubbed onto the C.D.R. somehow. With that to go on, we also found discrepancies in the C.D.R.s from the SeaStar, Carpenter, and Woods Hole.

"But how - " began the captain.

"I wish I knew," sighed David. "But the best men in the field say that you can't alter the record without destroying the crystal. And if that's true, then they weren't altered. That leaves us with an inside job. A very skillful inside job."

"I agree that someone inside the subs must have turned the C.D.R.s off," the captain mused. "You can't get inside a sub - peacefully anyway - without opening a hatch, and that's recorded, too. But suppose someone could gain control of the ship - wouldn't it be fairly easy to turn off the C.D.R.?"

"No," answered David. "You see, anything that affects the C.D.R.'s operation is recorded, too. Even if power to the laser case discharges and triggers a burst from the diodes. The crystal fairly screams on playback."

"So there's no way to stop the C.D.R. and record false data." "Apparently not. But apparently someone knows how to get around that little problem."

"So you set a trap for those unknown geniuses," said the captain. "You send out a sub with a full load of nice negotiable industrial diamonds and put extra people in to ride shotgun. Is that what's in their baggage?"

"Pretty much," smiled David. "We brought some small-caliber arms with explosive and knockout rounds, an assortment of gas weapons, and ..." he hesitated, "well, some special stuff."

The captain cocked an eye at David. "Special stuff, huh? Sounds as if you're planning some surprises. I don't suppose you'd want to tell me about them."

David shrugged apologetically. "It's not that we don't trust you, Captain, it's just ..." he hesitated again.

Captain Ahrens laughed. "Never mind," he said. "I understand. And I'm not sure I want to know anyway; I sleep badly enough as it is." He paused and looked at David closely. "I apologize in advance for this next question, and you may choose not to answer, but - isn't ambushing a little out of your line of work?"

It was David's turn to laugh. "A little, yes. But somebody had to take the responsibility for spending the company's money like this, and I am the lucky somebody. So I came along to, uh, protect my investment. Besides," he continued seriously, "if everything goes as expected, we are the ambushee."

Several days later, David was sitting in front of a forward-sonar repeater screen in the sub's tiny lounge, nursing a glass of iced tea and watching the ocean floor slip past below. They were moving over a region where two of the great plates which form the ocean floor meet, creating a nightmare seascape with vast sheets of granite crumpled and torn like paper. Jagged blades of rock thrust hundreds of feet up from the floor like shoulder blades of buried monsters, and mile-Long crevasses opened here and there, with bottoms too deep to be registered by the sonar. He suppressed a shudder at the hopelessness of finding a ship on that bottom.

A long ridge, broken by steep-sided notches, swam into view at the limit of the sonar's forward range. It stretched across the screen's full sixty-degree field of view, becoming fuzzy and indistinct at the edges. Here and there a peak thrust above the clearance bar painted across the display, and the Obstacle Warning System automatically put the big ship into a shallow climb. David closed his eyes momentarily and could sense no climb, but the clearance bar moved slowly above the peaks. Another ridge, and then another, moved into view, and the Obstacle Warning System kept the vessel moving slowly up to clear them. The view was almost hypnotizing.

David shook himself out of his reverie, and realized with some surprise that they had been climbing fairly steadily for almost half an hour. The terrain still rose in front of the ship, too; apparently they were going to keep climbing for some time. Funny, he didn't remember any such rise along their route. He decided to go up to the command compartment, and check with the navigator.

When he arrived a few minutes later, Captain Ahrens and the navigator were arguing heatedly over a contour map on one of the big wall displays. The navigator, a tall, thin man named Richards, was tapping on the screen with a pointer, and saying, "Dammit, Captain, we have lost almost three thousand feet of depth in the last half hour or so to that blasted rise, and it's not on this map!"

"Are you sure of where we are on that map, Mr. Richards?" asked the captain testily.

"Triple-redundant gyrocompasses don't lie," retorted Richards. "At least, they don't all lie the same way. And according to all of them, give or take a hundred feet or so, we are here!" he said, pointing to a bright pip on the display.

"Either we are not here, or that ridge isn't there!" returned the captain vehemently. "And I don't propose to run us aground to see which is correct!"

The navigator shrugged. "I don't see what real difference it makes. We either have to turn around or go up and over. The ridge is likely to be just as low here as anywhere." He gazed at the sonar display and shook his head.

"What's the trouble, Captain?" asked David.

"Oh, hello, Regis," said the captain. He waved a hand at the display. "We've been climbing for - " he touched his watch, "for almost an hour, over a rise in the ocean floor that's not on our chart."

"How new is it?"

"The chart? Oh, a year or so old, I guess. But then things change pretty slowly down here."

"I was referring to the ridge," said David. "From what I can see, that thing could have been pushed up yesterday. Looks pretty rugged."

The navigator shook his head. "No current down here to round any edges, no temperature differentials, no erosive forces of any kind - except maybe the fish."

"Anyway," put in Captain Ahrens, "a quake strong enough to move that much dirt would rattle every tooth on the planet and cause displacement tidal waves that would wash away coastal cities all around the basin." He bit his lip. "Nope, that baby's been around quite a while."

"Well, what now?" asked David.

"I think that's up to you, Mr. Regis," replied the captain. "Normally, we'd surface and get a bearing from the synchro satellites before proceeding. In the present circumstances though ..."

"I see what you mean. It might spook our friends, and this expedition is too expensive to ruin, if we can help it." He ran a hand through his hair. "Looks to me like we'd better do exactly what you would normally do," he decided. "Besides, I don't like not knowing where we are. Sorry, Mr. Richards," he said, turning to the glowering navigator, "no reflection intended, but something is obviously wrong here."

"Good!" said Captain Ahrens. "I was hoping you'd feel that way." He turned and touched a contact on his panel. "Prepare to surface for navigation check. Repeat, prepare to surface for navigation check." He looked back at the map, shook his head, and said, "O.K., pilot, take 'er up."

The submarine rose smoothly through the black, clinging water. As it neared the surface, Captain Ahrens turned to David. "If you'd like to come to the bridge with me, I'll have the pressure curtains drawn so you can watch the last hundred feet or so of the ascent."

"Fine," agreed David. "Maybe we can see the top of that ridge when we surface."

"I won't believe it's there until we run aground on it," muttered the navigator. David laughed and followed the captain into the passageway.

The bridge was located two levels above the command compartment, at the very front of the ship. It was a smallish round cabin, with windows all around affording a three hundred and sixty degree field of view, with the pressure curtains retracted. Several repeater screens were placed around the cabin above the windows, with ship conditions displayed on them. David sat in one of the swivel chairs at the room's center, and watched the sea turn from murky green to lighter shades.

A few fish were visible in the distance, but the sub's ascent was rapid enough at first to have disturbed most of the sea creatures in its path. At a depth of fifty feet or so, the sub slowed, and rose very gently. "Gives things a chance to get out of our way," explained Captain Ahrens. "Even at that, we almost always end up with a shark or something trapped on deck. They can get pretty smelly if they aren't found soon, too." David nodded understandingly, and gazed along the vast length of the ship, out to where it merged hazily with the sea. He fancied he could see a larger fish moving near the hull, but it was much too indistinct for certainty.

"Captain, a hull sensor reports collision with something small. Sector J, topside," said a loudspeaker. "No damage."

"Very well," acknowledged the captain. "Probably a floating log, or something similar," he said to David. He chuckled. "I remember an incident on my first sub cruise - "

A loud CLANK! interrupted him; a second clank followed immediately.

"More collisions, Captain," said the loudspeaker. "Both in Sector A, port and starboard, just below waterline. No damage there, either."

"Strange place to get hit," mused the captain. "The water flow tends to keep objects at a distance, for one thing, and whatever hit us is neither floating nor sinking. Sounds almost intentional."

"Look, Captain!" exclaimed David, pointing out the front window segment. Forty yards away, a scuba-suited figure on a one-man torp drove toward them through the water, with a hemispherical object slung beneath the torp. It reached the sub just as the bridge was beginning to breach the surface. Foam boiling over the windows obscured the view outside, but another metallic collision was felt just below the bridge.

"What was that!" shouted Captain Ahrens in amazement. "Was that a man?"

"I think so," answered David. "But what is a man doing out here? We're nowhere near land, are we?"

"Captain!" interrupted the radio. "Another collision - this one was right over our heads!"

"Yep, we saw it coming," replied the captain. "I don't - "

He was interrupted by the BEEP! of the all-hands circuit. At the same time, a panel marked "Ext. Comm." lit up above the display panel.

"Well, I'll be damned!" said the captain. "He's plugged himself into the external, communicator jack in the outer hull service panel."

"Ahoy, Cetacean!" came a strangely burred voice over the intercom. "You are captured. We have placed four magnetic mines on you, above your main hatch, below your forward waterline, and above your command compartment. If detonated, these mines will destroy your controls and sink your ship. The mines are radio-detonated; we suggest you don't operate your radios. You might pick the wrong frequency. Tune your transceiver to 1.23 megahertz; we will radio further instructions. We will also monitor 1.23 megahertz; we will detonate the mines if your transmitter power exceeds one watt. Repeat: tune to 1.23 megahertz; do not exceed one watt transmitted power." A sharp click followed, and the external communicator panel went out.

There was a moment of stunned silence as the water drained off the windows. David Regis and the captain watched the torp and its rider surge away from the Cetacean, toward a rather large nondescript cruiser that could be seen lying about a half mile off the sub's port bow. The wakes of several other torps converged on the cruiser as well.

"Huh!" grunted Captain Ahrens finally. "I hope you have some fancy tricks up your sleeve, Mr. Regis. Oh, well ... tune to that frequency, Mr. Carlyle."

"We're there, sir," came the answer from below. "No word, yet."

"O.K., Mr. Maclise, let's get some men out to look the mines over. Photographs, phones, magnetometers, Geiger counters, and anything else you can think of. We need to know what those things are."

"Right, sir," answered the crew chief.

"Mr. Richards, get me a new fix, and update your gyros. Mr. Carlyle, establish a send and receive at 1.23 megahertz, and mind that one-watt transmit limitation. Patch it in all over the ship so everyone can hear."

A pause, then ... "Done, Sir."

Captain Ahrens jerked a pair of binoculars from the rack above and looked at the distant cruiser. "Can't tell a thing about it," he said. "Looks like a converted - " He was interrupted by a voice over the speaker.

"Ahoy, Cetacean! No need to transmit at all. You will descend to fifty feet when this message is finished. Further instructions will appear on your forward-looking sonar display. Please comply quickly and completely with these instructions; otherwise we will detonate the mines and sink your ship. Watch your forward sonar screen, and begin your descent to fifty feet immediately."

Captain Ahrens turned and headed down to the command compartment, motioning David to follow.

"Belay that inspection order, Mr. Maclise. Get your men back inside, then report. All hands, prepare for descent."

As they entered the command compartment, the main screen flashed READY FOR DESCENT. "Take 'er down," nodded the captain. The huge bulk of the Cetacean began to slip below the surface.

Captain Ahrens put the forward-looking sonar display on the main screen, then sat back. As they neared the fifty-foot mark, bits and pieces of letters began to appear, and form words. The crew stared in astonishment. As the ship leveled off, the message stabilized. The letters were fuzzy and varied in contrast but could be read easily enough:

TURN OFF YOUR SONAR TRANSMITTER, LEAVE RECEIVER ON - STEERING COMMANDS WILL APPEAR HERE. DO NOT RADIATE - WE ARE MONITORING.

The message faded, and was replaced by another:

TURN OFF XMTR.

"O.K.," sighed Captain Ahrens. "Shut down the sonar, Mr. Richards."

"But, Captain," stammered the navigator, "we'll be blind."

"We'll have to trust them. We can do without sonar easier than we can do without a hull."

The forward sonar screen went black as the transmitter was turned off. A second later a band of white appeared, leading straight off into the blackness and dwindling in the distance like a highway. An arrow pointed along this path, and a legend under the arrow read 10 KTS.

"How are they doing it?" murmured the navigator.

"Same way they generated that ridge, I imagine," said David.

"Huh? You mean ..." Mr. Richards broke off and stared at David.

"Why not?" replied David. "If they can put their own roads and billboards on our display, they should be able to put terrain on there, too. We were riding through water with nothing in front of us, so they didn't have to worry about echoes from real objects interfering with their fake pictures."

"Sweet," nodded Captain Ahrens.

"They sit up there on the surface, and wait for our sonar pulses. When they know we're coming and where we are, they beam a phase/amplitude-adjusted signal back at us, and paint mountains on our display. We think we're lost - I apologize, Mr. Richards - and surface, where they slap magnetic mines on us. Oh, boy!" He ran his fingers through his hair, and slumped in the chair. "Oh, boy!"

Several hours later, David was sitting in the command compartment, warming his hands around a big mug of coffee.

"We can't really make any detailed plans," he said. "We have no weapons that can be used underwater. We've discussed various plans for use when - or if - we surface, but we can't pick one until we know the situation. We'll just have to wait and see what comes next, and then use whatever tactics seem appropriate."

The captain nodded. "Well, at least we'll know roughly where we are, for whatever good that does us. Mr. Richards says the inertial nav set won't drift significantly for several days and we ought to get wherever they're taking us before too long."

"O.K.," acknowledged David. "I've had a message made up to let the folks back home know what happened. We can send it as soon as we surface."

The captain shook his head. "We won't be able to get two words off. They'll blow the mines as soon as they hear us transmitting," he said.

"Oh, there'll be plenty of time for this message," replied David. "We brought a burst transmitter with us. It's a pretty clever affair: you just transcribe your message into Morse Code and put it into the computer, where it's time-compressed by a factor of about ten million, and stored. It's available for transmission any time after that. What we've done is to rig the unit to repeat the message until we stop it. The message runs about a millisecond when compressed, so we should be able to get off fifty repetitions before they push the button. Of course, it's a last resort; we can expect to be blown up when we start sending."

"Can we be sure anyone will hear it?"

"I think so," answered David. "We'll beam it to one of the synchronous satellites, and somebody will read it sooner or later." He paused, staring at the desk. "Not that it'll do us much good," he muttered.

"Looks like another jink coming up," said the captain, nodding at the main screen. The broad arrow marking their path appeared to take a turn in the distance.

"I don't know who they're trying to fool," grumbled the navigator, "but they can't confuse us this way."

"Maybe they're leading us around things," put in the captain. "Are we near any shallow water, Mr. Richards?"

"Nope," replied the navigator. "Could be some uncharted guyots, perhaps, but we're a good thirty hours away from any water less than about two thousand feet deep."

"Thirty hours, hm-m-m?" the captain rubbed his chin. "Are we headed in that direction?"

"No, sir, not right now," said the navigator. "But we've been headed more or less in that direction since we started." He touched a button on his console, and the forward sonar map flicked over to an auxiliary screen, to be replaced by an oceanographic projection. A dotted line meandered across the map. "Here's our course since we surfaced," explained Mr. Richards. "The small figures beside each leg of the course is our average speed." He drew a fingertip light-pen across the monitor at his console, and a streak appeared on the main screen. It pointed to a group of small islands in the corner of the screen.

"See how the general course leads toward these emergences? I make it - oh, thirty-five hours, if they don't change our course or speed much."

"That's about right," nodded David. "We'll be missed in another forty-eight hours or so, and those boys up ahead will have plenty of time to take out our Cruise Data Recorder, work their black magic on it, and dump it where they want it."

"We don't have much time to get a message out," muttered the captain. "We've got to do something!"

"We have to come up with something they aren't monitoring," said David. "Maybe we could hook up some ultra high frequency stuff." Mr. Richards shook his head. "If the pirates can't receive it, no one else will be able to. Nope, the radio is out."

"What else is there?" demanded the captain. "They're monitoring us acoustically, even if we had enough acoustic power to reach anyone else. We don't have any way to make much of a light - and besides, they would be sure to see it."

David's eyes narrowed suddenly. "Not necessarily," he said. "Suppose we use infrared?"

Captain Ahrens looked at him blankly. "If they couldn't see it, who could?"

David pointed up. "The big eye in the sky," he said. "N.O.A.A. has a whole fleet of satellites up there with multispectral scanners aboard. If we can make a bright enough IR light, they'll see us."

Everyone sat silent for a second, absorbing the idea.

"Now all we need is an infrared light source," said David finally. "Any ideas?" No one spoke. David slumped back into his chair.

"How bright does this thing have to be?" asked Captain Ahrens slowly.

"Hm-m-m," thought David. "Those scanners can detect temperature differences of a degree or so, but it has to be over a fairly large area - say fifty to one hundred feet across. A smaller source has to be correspondingly hotter.""I think," announced the captain cautiously, "maybe I know where to get your flashlight." He patted the cabin wall next to his chair. "Cetacean herself."

It was David's turn to look blank. Captain Ahrens leaned forward. "This vessel is propelled by a heat engine," he explained. "The wasted heat is discharged into the water flowing past us, and raises the temperature of that water. Right now, that temperature rise is small, because we're moving fairly slowly and operating efficiently. But we can make that water good and hot by increasing the pile output and venting the extra heat. We should be able to raise the surface temperature five or ten degrees, for twenty or thirty feet to either side of the boat. We can even leave dots and dashes of hot water by turning the pile up and down!"

David nodded in vigorous and pleased agreement. "Thanks, Captain," he said. "You've probably just saved our lives." He picked up a pen. "Well, what shall we say?"

Fifteen hours later, a bored photo-interpreter at N.O.A.A.'s satellite reconnaissance facility in Albuquerque picked up the next envelope in his IN chute, read the I.D. tag, and groaned. "The South Pacific M.S.," he said. "That's the second blasted multispectral I've had today!"

The man at the next console looked up. "You just don't have the right attitude, Fred." He produced a battered yellow handbook from somewhere, and waved it about. "It says right here in the National Oceanic and Atmospheric Administration Handbook on Satellite Photo-interpretation that 'resolution of multispectral anomalies represents the greatest challenge to the photointerpreter'. Don't you want to be challenged?"

"They don't pay me enough to challenge me this much," returned Fred. "Why doesn't somebody invent a computer that's smart enough to resolve those 'anomalies' itself?"

"Economics, my boy, economics. They can hire you cheaper than they can re-educate the computer. Besides, it keeps you off the streets."

"Yeah, yeah," muttered Fred, as he took the film strip from the envelope, and threaded it into his viewer. "Well, let's see what the computer couldn't understand this time..." The image that appeared in the viewer was a false-color presentation. Each of the nine bands that the camera operated in had been assigned a specific color, from red for the 8-14 micron band to blue for the 0.5-0.35 micron band. The result was a dazzling melange of color that would have been impossible for an untrained observer to understand. Even a highly skilled interpreter could scarcely have extracted one percent of the information contained in the composite.

The computer had seen it first, however. It had gone over the photographs micron by micron, using highly sophisticated optical/digital processing techniques to compare, correlate, transmit, reject or store virtually all of the information in them, and it required Fred's help on less than one-hundredth of one percent of that information.

Fred looked at the composite long enough to orient himself, then touched a contact. The screen almost went blank as the computer removed the uninteresting areas. He leaned closer, and began examining the anomalies. Area 1, a small irregular blob near the center that showed up thinly in the 0.9-0.8 micron band, was probably some stratospheric turbulence - a big jet-stream eddy, perhaps. Area 2 was a series of bright blue speckles that covered almost all of the left side of the image, It looked to Fred like noise in the camera electronics. A brief shower of cosmic rays could do it, also. Area 3 was a line of short red dots in the 814 micron band, in an area of deep ocean. It seemed too regular to be only noise. Fred asked the computer for a temperature differential between the spots and the background, and whistled in amazement when it came.

"Nearly five degrees centigrade over an area of - oh, twenty-five hundred square feet in the smaller dots!" he exclaimed. "Something down there is hot!"

"What is it?" The man at the next console came over and peered at the image.

"I don't know," said Fred. "A series of volcanic vents, maybe?" "Not likely," said the other. He glanced at the location code on the picture. "That water's deep there - a mile or so, at least. A series of vents would have to be within fifty feet of the surface to produce localized heating like that. And if the sea floor had come up that far any time recently, every seismometer in the world would be having convulsions." He looked closer. "Whatever it is, it's calling for help."

"Huh?" said Fred.

The other man pointed to the image. "There's a blob, then three dots, three dashes, three dots, a long space, three more dots, and a dash. S-O-S and another S."

"Does sort of look like that," Fred agreed.

"Could it be?" asked the other.

"N-n-no," answered Fred, thoughtfully. "In the first place, that's - let's see - almost half a mile from start to finish, down there. In the second place, it would take a tremendous amount of energy to heat up that much water. Anybody with that much controllable energy on tap shouldn't need help."

The other man laughed, "I was just kidding," he said. "You've probably got something highly reflective floating down there, and it just looks hotter. Wait and see if it shows up in the next pass."

Fred nodded. "Sure, I should have thought of that." He tapped the "Cycle" button on the console, and began examining the next frame. After several minutes, a puzzled look crossed his face. He rechecked the Greenwich Mean Time at which the scans had been made, then asked the console for local.

"Hey, Jack," he called the other interpreter. "That high reflectivity suggestion of yours didn't pan out, quite."

"How come?" asked Jack.

"It was just after midnight, local time, when those pictures were taken." Fred tapped his chin with a pencil. "I think I'll put a priority tag down for the next set of shots over that area."

Jack lifted his eyebrows. "You really think that might be a signal?"

Fred shrugged. "Won't hurt to see," he said.

"Captain, we're going to run into trouble if this thermal cycling keeps up." David Regis traced a finger across a chart in the manual on his desk. "According to the Test Standard, our heat-transfer chambers are proof-tested by twelve hours of rapid thermal cycling from zero to a hundred degrees centigrade."

"We aren't cycling over quite that range," replied Captain Ahrens. "The output water varies from about fifteen to eighty degrees centigrade."

"Yes, but we've been doing it for almost fifteen hours now," returned David. "Besides, these proof tests are usually made at a hundred and twenty to a hundred and fifty percent of the design performance requirements." He shook his head. "I've never been sure that we weren't just inducing damage during those tests. At any rate, I don't think we can trust the cooling chambers through much more of this."

"O.K., we've repeated our message several times now. Let's just run the chambers hot for a while. That will at least leave a continuous trail."

"Another five-knot increase, Captain." The navigator nodded at the forward sonar screen, where the legend now read 20 KTS.

"That's going to cut our signal down some," said Captain Ahrens. "We're going to be using most of the pile output just to push us through the water. Another increase like that and we won't be leaving much of a trail."

"We're going too fast as it is, to suit me," said the navigator. "We're going to make those islands in less than twelve hours at this rate."

"It's time to decide what we're going to do when we get there," said David, clenching his jaws.

"O.K.," said the captain, "we've got to assume that our friends up there are interested in the diamonds, rather than us. That makes us pretty expendable after they get the cargo."

"You're right. Our only chance is to stay with the sub as long as possible, and try to bargain if we have to. As long as we're inside, they can't get to the cargo without blasting a hole in the hull. I don't suppose they'd hesitate to do that, but we can at least make it hard for them."

"I don't think they'll want to do that," said Captain Ahrens musingly. "The sub itself is worth a hundred times the cargo. I can't see them spending this much money for anything the subs can carry. What were the other subs carrying?"

"Oil and ores, mostly. Now that I think about it, one of them was just carrying some specialty foods - it was on its way to pick up a load of North Slope Oil." David nodded to himself. "So it was the subs they were after!"

"That means some pretty big financial backing - too much for just a gang of modern pirates."

"We knew they were no cheapskates," said David. "After all, we still don't know how they can alter the Cruise Data Recorder. And this trick with the sonar," he gestured to the main screen with its superimposed highway, "isn't the work of amateurs."

"A thing like this could strain the resources of a small country," put in the navigator.

"So all we have to do is decide which country," said David.

"Country?" said the captain. "Are you serious?"

"Who else could use a fleet of nuclear subs? A company couldn't: the Nuclear Fuel Authority monitors all the fuel for commercial shipping."

"That narrows it down, some," said the captain. "Whoever wants the ships has to have all the supporting technology. And there aren't too many nations around that have the technology but not the subs."

"Well," said David, "that still isn't getting us anywhere. We have to decide what to do now."

"I'm for sticking with the sub, and waiting them out," affirmed the captain. "If they detonate those mines, we'd be in trouble, but I think they want the sub too much for that."

"Could we tell them that we've rigged the engine to explode if the hull is breached? Maybe that'll keep them off our necks for a while."

"The pile can't be rigged to fission," said the first officer. "The fuel is embedded in graphite rods, and you can't get enough of it close enough to exceed critical mass."

"I know that," said David, "but do they know it?" The men stared at each other, weighing the idea.

Captain Ahrens shrugged, and broke the silence. "It's worth a try."

At almost the same moment, a display panel in the photointerpreter's room at N.O.A.A. Albuquerque lit up, proclaiming PRIORITY LOADED. A man at a nearby desk noticed, and called, "Fred, your priority shots are here."

"O.K., thanks." Fred returned to his desk, touched a contact, and nodded to himself. Another contact wiped out everything on the screen but the eight-to-twelve micron imagery. Fred stared at the line of tiny dots and dashes extending across the screen. Then he picked up a card marked "Morse Code," slipped it into the "Program" slot on his console, and tapped out the dot pattern on his screen. When he finished, he tapped another key, and accepted the strip of tape disgorged by the computer. He read it over, slapped the console off, and headed for the door.

"Hey, Fred, you leaving already?"

"No, I'll be back. But I think I may have earned my salary today." Fred waved the slip of paper and left almost running.

"...And that's about it," said David Regis. He was sitting in a huge green chair by an equally huge window that looked out over a wooded park. He sipped at a drink.

"After we got to their base (which turned out to be a beautiful natural cavern under one of those little islands), we just sat there threatening each other. They blocked up the entrance so we couldn't move the sub, and I think they would have detonated the mines to get to the C.D.R., if we hadn't bluffed with a 'rigged' engine pile. But the cavalry got there finally, so here I am."

"Extremely well done, David," said Colonel Woell. "Using the engine's waste heat as a signal was ingenious."

"I thought so, too," agreed David."Bill Ahrens can be mighty proud of it."

"I understand that you resolved the method used by the pirates to alter the C.D.R. data."

"That's right," replied David. "Actually they didn't alter anything. They simply removed the C.D.R. crystal, put in a blank crystal, and transferred all of the preliminary information from old to new, at very high information rates. Then they finished by impressing a prerecorded sequence simulating the sub's destruction on top of that. Very straightforward, and very ingenious."

A bell chimed softly somewhere. Colonel Woell touched a contact on his desk, and quickly read the message on the desk screen. "Excellent, excellent," he said. "David, the other subs have been located, from the information we obtained from the captured pirates. Discussions with the government responsible are under way, and we will doubtless have the subs and cargoes and crews back soon."

"Crews?" said David in amazement. "The crews are alive?"

"Apparently so," smiled Colonel Woell. "They have been kept alive to teach the subs' workings to the people who were assigned to operate them. We should get them all back."

"That's wonderful!" cried David. "That makes the whole venture worthwhile. I don't mind telling you that there were a few times I was sorry I ever started this." He shuddered. "When I think of those magnetic mines stuck to the hull of the sub ..."

Colonel Woell looked puzzled. "I can understand your being worried at the time," he said, "but now that you know there was no danger ..."

"No danger?" said David. "If those jokers had leaned on the wrong button, I'd be fishfood now!"

The colonel broke into a slow grin. "You mean you don't know about the mines?"

"Huh?"

"The mines. They wouldn't have worked." While David gaped, he shuffled through a file folder on his desk. "Ah, here it is," he said, and handed a sheet to David. "The technicians who removed those mines found that the firing mechanisms were completely corroded. Whoever modified the mines to be triggered by sonar apparently assembled the triggers in a dusty atmosphere, because sand scratched the valve seats and perforated the seals. Seawater got in, and ate up the insides."

David read the memo, shaking his head slowly.

"We played our hand closer than we knew," he said. "According to this, the trigger latches were released on all those mines. They probably did try to detonate them." He drew a deep breath and laid the memo aside. "Looks like the Cetacean was saved by some Foreign Object Damage," noted Colonel Woell. "I'm rather pleased about that, even though you and Cetacean's captain had already solved our problem."

David laughed. "I'm pleased, too. This business has allowed me to satisfy a lifelong ambition."

"I didn't know you were a frustrated cloak-and-dagger man."

"Oh, no," said David quickly, "that's not the ambition I meant." Colonel Woell raised his eyebrows. "You see I've always wanted to have tangible evidence that I was worth my salary. And since it was my idea that resulted in saving four subs, worth maybe forty million dollars apiece, and it costs the company about seventy-five thousand a year to support me and my office - let's see, I've been here ten years so that's seven hundred and fifty thousand - I've cost the company three-quarters of a million dollars. So if I never make another dollar for the company, we will be even in - let's see - about two hundred and thirteen years." David leaned back contentedly.

"Don't start relaxing too soon," replied the colonel. "You actually have fewer than twenty-five years paid up, so to speak."

David looked at him.

"You've forgotten," said the colonel, "that the company only pays five percent of the savings resulting from employee suggestions."