Jurassic Pouch Part II: The Caves of Yucatan
Previous: Chapter Twenty: The Marcel Loubens
Petra led the little group below, and led them aft down a narrow corridor. “You each get your own stateroom, such as they are,” said Petra. Feel free to drop your bags in them.
The aft end of the ship was dominated by a sturdy crane capable of loading and offloading goods from the ship’s cargo hold, to and from land and water. At the foot of the crane was the ship’s cargo hold. Like the rest of the deck covered by solar-panel decking and a stout titanium frame.
The cargo hold was covered by a pair of solar panels, each two meters by one. Petra’s deckhands used hooks to open them. One of the hatches briefly caught the afternoon sun in a blue-green flash that left Bender temporarily blinded.
The cargo doors, opened, now lay on the deck: Merl wasn’t surprised to see that the undersides of the doors were also coated in solar electric material. Not a kilowatt-minute wasted, thought Merl.
“Behold Le Garage,” said Petra.
Bender and the others bent over the darkness of the hold.
Le Garage was a large black box of metal, a meter deep by two meters square. Camera turrets and lights topped one edge. Resting on the top surface was a bright orange marker buoy.
“It’s not much to look at from the outside.
But inside are two submersible drones. They’re fully autonomous. They were developed by the petroleum industry for offshore drilling operations, but we use them to explore dangerous ship wrecks. We call them Roberta and Floyd.”
“The buoy is for communication with the surface. It’s on a fiber optic tether paid out by the ship, up to 10,000 meters long, in case the water surface directly above the garage is unsuitable, or, “ – here Petra shot a subversive look to Bender – “inaccessible. The tether length limits the effective depth of operation, incidentally. The coastal waters of Yucatan, called the Yucatan Shelf, aren’t nearly that deep, 200 meters at maximum.
“How do the drones communicate?” asked Merl. “Radio doesn’t work in sea water.”
“They don’t work through limestone very well, either,” replied Petra. “The drones communicate with each other, and, when possible, the garage, using ultra high frequency audio. Think of it as underwater Morse Code that only bats can hear. In turn, the garage relays signals (in both directions) to the buoy along the fiber tether, which has ordinary wireless connectivity to us. Each communication with a drone involves sonar, fiber, and radio. If any link in the chain fails, no communication for us.”
“But I said the drones were ‘fully autonomous’. They are, and in clever ways. For one thing, as long as they are within communication range of each other, each keeps the other apprised of what it’s doing, and what it’s seeing. Each knows what the other knows, in nearly real time.
“If one drone gets stuck, whatever data it collected can be returned to the surface by the other. But the onboard AIs use the shared data too for planning and navigation.
Using a crane, the crew of the Marcel Loubens lowered Le Garage into the water off the starboard side.
The two divers were ready. Bobbie bit down on the breathing regulator, pitched backwards off the starboard gunwale of the Marcel Loubens, and plunged into the water. Terry followed suit. The two bobbed to the surface, and swam a couple of meters to Le Garage. The two divers placed hands on the floating submersible to steady themselves.
Aboard the boat, Petra untied the spring line from its kevil and tossed the end to Bobbie, who caught the rope before it hit the water. Bobbie clipped the end of the line to a dive belt karabiner, while Terry removed the shackle which still secured Le Garage to the sailboat’s crane hoist. This done, the two divers and the submersible were now on their own.
Petra called out from the deck. “Everything looks good here, just bleed off the BC when you’re ready.” Bobbie gave a thumbs up and opened a valve on the air-filled buoyancy compensator, a bright yellow bag mounted on top of Le Garage, and massaged the bag to help it deflate. Soon the divers, and their strange contraption, disappeared below the surface, in a cloud of bubbles.
“Now what?” asked Merl.
“Now,” said the Captain, “we wait to see if they come back.”
The human divers were back within the hour, sans Le Garage, which now lay on the sea floor, facing the underwater cave entrance. One of the divers handed the end of a thin cable to Petra before accepting a hand up the ladder from Bobbie, who grasped the handle on the back of the diver’s air harness and lifted the diver to the deck with the strength of one arm.
Petra attached the end of the fiber optic cable to a small bouy, and tossed a lead weight overboard, which played out a spool of piano wire from the deck as it sunk to the relatively shallow bottom of the coastal waters. The payout mechanism sensed the slack in the line when the anchor struck bottom, stopped, and chirped “Depth, 200 meters”.
Petra cut the wire and attached it to the buoy and cast it overboard. Petra keyed their comms mic. “Sparks?” You getting signal? The reply crackled back from the radio room of the ship. “Fine business. Minus 1 dB on the fiber link, and 5 by 5 us to the buoy.”
Petra cast the comms buoy into the water, and the Marcel Loubens sped away quietly under battery power, across a moonless sea.
In the radio room, Sparks set the vessel’s main communications mast to TELESCOPE AUTO. As the Marcel Loubens gained distance from the comms buoy, the top of the mast slowly raised higher to keep the sea-level buoy within its radio horizon, while minimizing the boat’s radar profile.
The others gathered in the conference room, turning the chairs to face the panoramic monitor which dominated one end of the room.
Petra conferenced Sparks in from the radio room. “We’re all up here in Conf. Whenever you’re ready.”
Sparks replied, “Roger chief, Le Garage is doing self-test, I’ll have video…. now, actually.”
The center third of the panoramic display lit up, showing a grainy blackness as Le Garage’s camera. The only images were patchy noise artifacts. A moment later, Sparks turned on the camera’s floodlight. The image brightened, but there was little to see, a pale green glow diffused by sediments mobilized from the sea floor.
Sparks added a status display to the view. “The camera is pointing downslope five degrees, into the cave entrance. There’s a rip current, not a bad one. Less than a meter per second. Left to right in your view. Starting LIDAR scan of the cave entrance.”
A bright green mesh appeared, crisscrossing the view as the laser scan began. An underwater cave passage, oval in cross section, extended downwards into darkness that not even the laser could penetrate. Sparks added a scale reticle to the view, and positioned it across the image of the cave entrance. “Five meters wide by 1 meter tall. The lidar is bottoming out at 200 meters range, so the passage goes at least that far.”
Frick and Frack, the two robot sumbersibles, left Le Garage. Frick led the way as the two dived deep into the underwater cave. The two moved slowly. Moving too quickly would disturb the sediment of the cave floor, and these two robots knew exactly how much time remained until it was time to turn back.
Each drone carried an array of camera eyes, each lit with a superbright lamp. This was not a dark environment, though no light had ever shone here before. As the drones collected data, sonar and lidar mapped the underwater environment around them.
After a few hundred meters of relatively tight passage, no more than a few meters across, the twin drones emerged in blackness. Slowly the drones’ cameras adjusted to the darkness. The passage was wider than the Channel Tunnel and almost as tall. Liquid green stalagmites connected floor to ceiling in an exquisite limestone collonade.
The drones noted this, the contours of every obstacle added to their limited machine consciousness every moment. What a stalagmite meant was beyond their ken: to document it and not crash into it was all the drones cared about, or ever could. And to return home safely.
Once a minute, the two drones paused, hovering side by side in mid water. The two drones exchanged copies of their data. Each voted. Go ahead? Go ahead.