On the icy surface of Lake Superior, Sam slowly deflated his buoyancy wing until he was negatively buoyant and started his descent. Like their previous dive, they descended quickly, free-falling 170 feet before leveling out.
He switched on the Sea Scooter’s electrics. The soft red glow of the machine’s instrument panel lit up like the dashboard on a motorcycle. “How are your gauges looking, Tom?”
“Good,” Tom confirmed. “Yours?”
“All good.” Sam checked his digital compass, setting a bearing for the J.F. Johnson. “All right, let’s go.”
The twin Sea Scooters whirred into life, quickly reaching their maximum speed of 4.6 miles per hour through the pitch-dark waters of Lake Superior’s seabed. Sam switched his headlights on for a moment to confirm there was nothing but cold water ahead of them, before switching it off again to conserve power. Riding in the dark, Sam turned his concentration to his sonar display, which gave a visual outline of the submerged seascape ahead of them.
Within minutes the large outline of the J.F. Johnson’s hull came into view. He altered his course another degree to the east, setting up to make a direct approach for the single opening on the portside of the listing pilothouse.
It took a total of fourteen minutes to reach the main hatchway at the base of the pilot house. Sam and Tom kept their headlights and flashlights switched off so they could see if anyone else was already on board the shipwreck. They both carried shark-sticks in case they ran into trouble, but their aim was to remain hidden if anyone came on board so they could see what they were shipping and where they were disappearing to over the twenty-four-hour period before the ship returned again.
Confident that they were alone, Sam switched on his flashlight. The entrance lit up beneath his beam, revealing the ascending stairs to the wheelhouse, the horizontal passage to the opposite end of the hull, and the open hatchway leading to the descending entrance to the lower decks. The same place where Tom had nearly drowned after his attacker merely closed the door.
Sam had no intention of repeating that incident this time round. He swept the beam of his flashlight across the hatchway, over the hinges, and all the way along the edge of the door. He was searching for any iron eyelets or latches, where the hatch could be permanently locked from the outside. It’s one thing to be attacked or become temporarily lost once inside, but a totally different, and far more frightening event to be sealed within — to wait until their gas supply eventually ran out and they drowned.
No way I’m letting that happen.
Sam finished running his beam along the exterior edge of the entire hatch, confirming there was no way they could be locked inside the wreck, either by accident or by the divers from the Superior Deep.
He swung the door open and closed. The hinges were obviously new — certainly not original anyway — and the hatchway moved freely. Sam glanced at both sides of the door. The main latch was rusted in the open position. He studied the rest of the door. There was no other possible way to become stuck.
Sam slowly pulled himself through the opening, turned and proceeded with the same process on the opposite side of the door. The hatch appeared free of anything that could be locked, but a single rusted iron eyelet was welded to the heavy bulkhead to the right of the hatch.
With his gloved hand, he took the iron eyelet in his grip and pulled. Despite nearly nine decades of rust, the ring was solid. It would take a lot more than they had to break it if they needed to. He swept the flashlight beam from the eyelet back to the hatch. There was no sign of anything that could be used to lock the door onto it. Sam guessed the device might have once been used to hold the door in the open position, when the J.F. Johnson still sailed.
Sam fixed his beam on the eyelet. “What do you think of this?”
Tom ran his light across it. “I wouldn’t worry.”
“You don’t think it could be used to lock us inside?”
“No. It could be used to lock us inside, but then, whoever did so would be trapped here, too.”
Sam smiled. “I hadn’t thought of that. Good point.”
He removed a small device from a small pouch on the side of his diving vest. It was cylindrical in shape and small enough to fit comfortably in a single one of his gloved hands.
Sam switched it on and attached it to the bulkhead to the left of the hatch, somewhere low enough that any movement would conceal its view with silt. There were no little blue or green display lights to show that the device had been switched on. He gently pushed himself backward, until he could stare at the hatchway.
A small upward crease formed on his lips. The device was almost undetectable without knowing precisely where it had been placed. There was no way any diver would stumble across it and even if they did, it was even less likely that they would have any clue what it was.
The device was an underwater location beacon known as a ULB. It was a smaller version of the one used in aviation, fitted to flight recorders such as the cockpit voice recorder and flight data recorder so that crashed aircraft flying over water could be located. It transmitted an ultrasonic 10ms pulse once per second at 37.5 kHz. The sonar used on the Sea Scooters would pick up that pulse as it bounced around the interior hull, creating a visual map, the same way bats used echolocation.
As a consequence, despite any damage to the silt within the confined space of the inside hull, both of them would have a real-time map of how to return to the hatchway. Ideally, they would have laid out guidewires, but that would have given away their position to whoever might follow them inside.
“Are you picking up the signal, Tom?”
“Got it.” Tom calibrated his instrument panel toward the ULB. “Where do you want to begin?”
“You said you originally followed your attacker below decks, toward the aft storage compartment, before he turned and fled?”
“That’s right.”
“How about we start there, then.” Sam glanced at the dark outline of Tom’s face mask. “Do you think you can remember how to get there?”
“Sure. I found my way out of there in a total blackout, I’m sure that I can find my way back in now the water’s clear again.”
“Good man.”
Sam watched as Tom recalled the image of the interior hull that he’d mentally constructed the last time he entered the J.F. Johnson wreckage. Sam couldn’t help but admire Tom’s ability. He moved with the confidence of a dive master, leading a tour through a wreckage he’d been to a thousand times before. Despite nearly being killed there only three days earlier, the man dived without displaying any apprehension, let alone trepidation.
He switched off his own flashlight. In the darkness, Sam followed the haze of Tom’s light, as he led the way down the first two sets of metal stairs into the long passageway heading aft. Tom moved quickly, and Sam found himself having to work to keep up.
Using long, powerful strokes with his fins, Sam followed Tom to the end of the passageway. There, Tom swept the area with the beam of his flashlight. A metal door blocked any further progress into the ship.
Sam switched on his flashlight and shined the beam across the door. “It looks brand new.”
Tom gripped the aluminum handle. “No way this has been down here ninety years.”
“I bet whatever’s behind that door is worth a fortune.”
“Enough worth killing for, anyway.” Tom gripped the handle and sighed. “But we’re not going to find out any time soon.”