Tom Swift and His Subocean Geotron (16 page)

The preliminary workup displayed a vehicle with a boatlike lower hull, enclosed on top and tapering to a point fore and aft. "Looks like a mole to me," joked Bud. "A mixed-up mole with a pointy snout in back as well as up front!"

Tom, invigorated, laughed at the comment. "Call it a mole-mobile if you like, flyboy. It travels underground, and I’m hoping it’ll allow us to reach and recover the crypt."

Chow scratched his bald head. "Now son, are you thinkin’ you’re gonna ride around in that thing? Way down in th’ dirt?"

"Compressed crustal material, Chow, a whale of a lot denser and tougher than plain ol’ dirt!"

"Guess she’ll make quite a hole."

"Not at all," Tom began.

"I get it," Bud interrupted. "It’s like your lithexor. You’ll use those geo-repelatrons to push the ground away—and then when you pass by, the ground just eases back into place without leaving a tunnel."

"Exactly right! I took some concepts I’d already developed for my earthdrone project and adapted them to a much larger manned vehicle. Basically, the localized repelling forces affect the solid ground in a radius of about one hundred feet; the size of the affected area is so large in comparison to the vehicle that even a small percentage of additional compression will open up a temporary gap, just wide enough for the vehicle to shove its way forward."

Tom explained the general principle of the geo-repelatrons—which gave the mole-mobile its name, the geotron—to Chow as the cook listened patiently. "Not a bad idee, I’d say," he approved. "You gonna drive her straight from Shopton t’ that place under the ocean, right through th’ ground?"

The youth grinned. "Pardner, if we went dead-straight and cut across the world from here to there, at the middle we’d be hundreds of miles beneath the surface—too much pressure for even the geotron vehicle to handle!" He explained that the craft would be conveyed to the South Pacific aboard the mammoth research ship
Sea Charger
, designed by Swift Enterprises. "As you know, the
Charger
can really
haul
out on the ocean."

"Okay, but just how do you get down
to
the seafloor from the
Charger
?" Bud inquired. "I know the
Charger
can submerge, but I didn’t think she could run all
that
deep."

"She can’t," Tom agreed. "So I’ve designed the geotron-mobile to be a real
subocean
geotron. She’ll maneuver like a sub down to the bottom, and then dive in to the earth."

"Subocean geotron..." repeated Bud Barclay. "Let’s call her― "

"Aw now, jest you wait, buddy boy!" interrupted Chow. "You’ve put yer brand on a lotta Tom’s inventions! Let me take a crack at a name!"

"Come on, Chow, I
did
let you name the spectromarine selector," Tom winked. "Besides, I told Bashalli about the idea this afternoon, and I—er—conceded that she could come up with a name."

Chow crossed his plump arms. "Uh-huh. Basherelli. I kin hardly wait."

Tom looked a little sheepish. "Um... she wanted to name the geotron the
Gee!-Oh
!"

"Musta been right hard to talk her outta that one."

"I... didn’t try."

Chow and Bud engaged in some shared eye-rolling.

It took Swift Construction Company on the other side of town, which often handled Enterprises’ large scale construction jobs, three days to assemble the moving-van-sized geotron. Tom and his father supervised the careful testing of the result, watching as the mole-mobile’s repelatrons flexed their muscles, shoving aside huge, heavy blocks of various materials and registering the force on massive piston-spring scales. "Perfect!" exclaimed the son. "You know, Dad, I’ve heard it takes some companies months or years to turn plans into working prototypes."

"And
I’ve
heard Tom Swift lives in his own spacetime continuum where impossible things happen daily," replied the father with eyes twinkling.

At last Tom and Bud eyed the big craft as it stood in "drydock" in the midday sunshine.

The high-sided
Gee!-Oh!
was covered with dish-shaped repelatron radiator units, row after row, recessed into contoured sockets in the hull. Most of them pointed outwards at right angles to the hull, but there were also some on the two "snouts" aimed fore and aft. "Pressure comes at us from all directions, on all sides," Tom noted to his chum. "There are more rows of geo-repelatrons on the topside."

"But no window for human eyeballs," commented Bud. "How’s the pilot supposed to see where he’s going?"

Tom smiled. "A viewport wouldn’t be very useful down in the middle of solid ground! There’s a TV setup for external viewing underwater, though."

"What about when she’s underground?"

"She’ll run on instruments that can penetrate the solid environment—the penetradar and LRGM gravity-mapper." Tom acknowledged that scanning instruments of that sort might not produce a detailed enough response to allow them to locate the buried memory crypt. "Those ‘human eyeballs’ can do jobs machines can’t yet manage alone. So I do have a special imaging system aboard. Remember the repelascan device that we use on the aquatomic tracker? I’ve come up with a way to convert the resistance-feedback response into visible imagery. I call it― "

"A repelascope."

Tom grinned in surprise. "How’d you know that? I haven’t mentioned the name to
anyone
yet!"

"Genius boy, you’ve put repela on just about everything around! I’m expecting a
repela
-skateboard any day now."

The geotron had passed all its preliminary tests at Swift Construction; now the boys were to try it out in action, through and under Lake Carlopa. As Tom signaled with a remote-control unit in his hand, small motors pushed open the vertical seam that split the hull into two halves that rolled on extensible tread units. As the sections slid like a sleeve along the interior hull, the access hatch was revealed. Tom and Bud passed through a high-pressure airlock and climbed up to the small fore-cabin.

Tom spent a long time scrutinizing the instrument board. "The
Gee!-Oh!
’s a pretty complicated piece of work, flyboy," he said. "And all those ’trons really scarf up the power—it takes
nine
neutronamos to run the thing!"

"Jetz, Hoover Dam on wheels!—er, flexi-treads."

At last the two halves were slid back together and sealed, and the geotron began to crawl forward on its treads. It eased into the access channel that linked Swift Construction Company with Lake Carlopa, less than a quarter-mile distant.

Tom noted a small structure on the video monitor, a few hundred feet beyond the facility’s perimeter fence. "The old Swift homestead. I think Great-Grandfather Tom and his dad Barton would be pleased to see where human invention has gotten to."

"You’ve done ’em proud, Skipper."

Though constructed of lightweight materials—a single-plate Neo-Aurium hull enclosed a honeycomb support structure of the same sort developed for the lithexor and earthdrone—the vehicle was very heavy nonetheless. It sank immediately to the bottom of the channel, which was just deep enough to cover it over. "Buoyancy is definitely negative," Bud remarked humorously. "Do you plan to just drop her over the side of the
Sea Charger
and let her sink like a boulder?"

Tom grinned. "I didn’t think of that! No, the geo-repelatrons can be swiveled by up to thirty degrees in their sockets and can be used for propulsion. When we’re in aquatic mode, we’ll use them to reduce pressure all around us to produce buoyancy, as we do in our hydrodome shuttle platforms; although in this case there won’t be a visible bubble.—You can say ‘holy bubblevator’ now, pal."

Bud looked scornful. "You must be thinking of someone else!"

The
Gee!-Oh!
rolled along the bottom of the channel and into the lake. Rather than sinking to the lake bottom immediately, Tom activated the repelatrons and adjusted the vehicle’s buoyancy. He was pleased with the smooth, instant response. "These localized-field repelatrons are subject to much less of the lag-effect than the kind we use on our spacecraft," Tom told Bud. "They can be retuned to the surrounding materials much more rapidly."

They cruised through the lakewaters at a moderate depth and speed. Tom kept in touch with his father at Enterprises by means of a Private Ear Radio, which was unaffected by the intervening water and ground.

Once the boys were well offshore, Tom began to take soundings with the fathometer. Gradually the depth readings increased to sixty feet.

"This is far enough out from shore," the young inventor said. "Let’s take her down."

His hands moved swiftly over the control board, diminishing the repelatron-induced buoyancy. The geotron plunged toward the bottom.

Bud was too busy studying the operation of the controls to watch the play of freshwater life as they settled to the green-lit lake bottom, made bright by the craft’s electronic lamp beam. Presently he glanced at the video screen. "Lake Carlopa’s not all that exciting from underneath."

"Seems like yesterday I was down here with Bashalli in the atomicar," was Tom’s offhand response. "Now for the
real
test." He shot Bud a tense smile. "Ready to make like a mud puppy, pal?"

"As ready as I'll ever be. But first check me out on these repelatron controls. As a
professional
seat-of-pants pilot, I never depend on the simulations, you know."

"All guidance and control is worked by computer, so the job of piloting is fairly simple," Tom explained. "Altogether, there are eighty-six separate repelatron radiators spaced around the hull, inset flush. For a steady course, just set the compass heading and the angle of elevation or depression on these dials. The computer takes over from there and activates the proper repelatrons and buoyancy level. Or, if you flip this toggle switch to ‘manual’, you can steer directly through the control stick."

"Sounds like a breeze!" Bud declared. "That all there is to it?"

"That’s all. Just for a start, let’s burrow down at a 60-degree angle, dead ahead. Got your seat straps buckled?"

"Right, Skipper."

"Okay, here we go!" Tom set the dials and flooded the geo-repelatrons with their tidal-surge of power.

Slowly the geotron’s stern tilted aloft as repelatron beams pushed against the lakebed and inclined the craft to the proper angle. The interior frame of the control cabin rotated to keep its passengers level. As Tom manipulated the controls, the craft nosed downward into the sediment.

Like a huge sea worm, the geotron nuzzled its way through the ooze. Bud sucked in his breath nervously as the video monitor went black and a sinking sensation—which was much like fear—took root in his stomach. Tom nodded at the monitor with crisp approval as the last glimmerings of underwater sunlight were shut out. He switched over to the repelascope system, and the screen showed pebbles, rocks, sand, and layers of clay crawling by.

"M-man, it’s
eerie
down here," Bud muttered in a hollow voice. "No place for somebody with claustrophobia. Not that that’s a prob for
me
, of course."

"It may be eerie, but a geologist could read centuries of history just from what we’re seeing. And there’ll be a lot more under the Pacific."

"Right. What’s our speed now, Tom?"

"About three knots."

The craft slowed as it penetrated into denser, harder strata of the muck that undergirded the lakebed. Tom switched to "manual" to try steering by hand. Several minutes later the geotron began to roll unsteadily from side to side.

"Whoa! Take it easy, Tom!" Bud said. "Are you trying to make me seasick?"

"I’m turning a bit green myself," Tom retorted. "We’re gyro-stabilized, but I underestimated the sharp differentials in the pressure gradients. I’ll install a gravitex device to keep her steady."

By adjusting the power and keeping a defter touch on the control wheel, Tom finally managed to hold the geotron at a stable angle. When they were eighty feet below the lake floor, he leveled off and headed straight toward the margin of the lake opposite Shopton.

Tom now made a further adjustment to the repelascope to scan a greater distance ahead. A weird scene leapt into view, a mass of cloudy contours, bulges, and cracks, with what seemed to be rocks scattered everywhere. "The system ‘overlooks’ interstitial material. You’re basically seeing the ‘surfaces’ of areas of higher and lower density and variations in composition," Tom said. "The coloration is artificial, painted-in by the computer to make the image more understandable." He told his comrade that the effective range of the repelascope was about two hundred feet. "That’s not very far, I’ll admit, but the geotron moves pretty slowly through solid ground—we’re not likely to slam into anything unexpectedly."

Presently the instruments showed that the
Gee!-Oh!
was approaching the lakeshore. "Want to come up for air, flyboy?"

Bud nodded and gave a slightly forced grin. "Guess I wouldn't mind. It’s great playing down here among the worms, but I’ll admit to feeling a mite claustrophobic after all, I guess. Plan to turn her around up topside?"

Tom shook his head as he pulled back on the control wheel and sent the geotron angling upward. "I’ll surface, but there’s no need to turn around—we can just stroll back to the duplicate control cabin at the other end and turn the stern into the prow. That’s why the geotron’s designed this way; you never know if you’re going to find a convenient place underground to make a U-turn."

The climbed at a shallow angle to the surface, avoiding the water completely and crawling out onto the beach—a narrow strip bordered by pine trees. "Back on top and still three-dimensional!" Bud exclaimed in obvious relief.

"With an audience!" Gazing at the exterior video monitor, Tom halted the geotron.

Straight ahead, at the edge of the trees, were several people. They were kneeling or crouching in the brush, and all of them carried binoculars. Their arms and mouths were in violent motion—their faces white with terror. It didn’t take a microphone and speaker to gather that the geotron didn’t just have an audience, but a panicked audience in full
scream
!