PANAMA CITY, Fla. -- One morning Pfc. Stephen Olinger stepped out into Alligator Bayou on the Panama City coast during an Army Engineer Diver Course Phase II exercise. As he sank farther into the murky waters, he saw a shadow pass above him.

He froze for a moment, petrified by the image. But then instinct kicked in and he resumed the exercise, knowing his crew would watch out for him from the surface.

Months later, Olinger still does not know what type of creature made that silhouette -- a stingray, or perhaps an alligator?

"I just clenched down on my mouthpiece," Olinger said. "And hoped it wasn't anything coming my way."

That type of trust does not happen easily. Students build it from weeks in the classroom and strenuous early morning workouts at the U.S. Naval Diving and Salvage Training Center in Panama City.

"That buddy could be the difference between life and death," Olinger said. "So I trust everyone in my class to perform their best."

Although in the deepest depths, Army engineer divers often must operate alone in the darkness with little to no guidance from the crew on the surface.

The world's five oceans, where many of the roughly 150 Army divers throughout the world perform, can be ruthless. The sea is an unpredictable, faceless adversary unlike any other Soldiers face on the battlefield. But no less deadly.

Its grip at the ocean's bottom can swallow divers like a black hole. Its currents can pull Soldiers sideways and in one mighty swoop, divers cannot tell down from up. Floating sediment and mud can limit divers' vision, further fogging their already limited sight lines.

"It's Mother Nature, you know. She's brutal," said Navy diving instructor Petty Officer 1st Class Nathan Emmett. "Everything in the water swims better than you and breathes better. We're just there. It's Mother Nature and we are 100 percent at her mercy."

As the underwater visibility dims, divers have no frame of reference to gauge distance, and no method to measure how fast they descend. A shadow or rays of sunlight occasionally penetrate the depths.

Divers often only have their hands and the bubbles from their breathing tube to guide them.

"It's almost like working on another planet," Olinger said. "You have to learn how to operate on that planet first before you learn to do anything else."

When a diver descends into an ocean or river, the greatest enemy may come from within. Divers face whipping waves and currents. Unknown marine life such as alligators or sharks could be lurking nearby.

The urge to panic can become so overpowering -- so encompassing, that it can break the minds of even the strongest athletes. Rushing water can affect the human psyche so severely, that it has been used during interrogations by Chinese and U.S. forces.

A Soldier must not only overcome their fears; they must harness and tame them. Few possess the rare ability to keep calm with water rushing into their nasal cavities.

Divers withstand not only the physical demands of continuous swimming, but they have to develop the level-headedness to think clearly under relentless pressure of tidal waves.

Can they hold their own lives and their fellow divers in their hands?

"If you're not comfortable," Olinger said. "That sort of panic will rise up … and take control of you."

Like the Phase I instructors at Fort Leonard Wood, Missouri, the Panama City cadre watch for "bolters" or students who could potentially flee under duress. If they ascend to the surface too quickly, their joints will feel the effects of gases that still remain in their bodies.

Once, a panicked student swam frantically to the surface during an exercise and took four instructors connected to the same oxygen tank up with him.

In the first month of training at Panama City, master diver instructors will compile a list of students who are most at risk to bolt for the surface.

"You can't teach presence of mind and not panicking," said Sgt. 1st Class Tom Kneipp, a master diver and former cadre instructor. "You either have it or you don't."

Soldiers could also suffer from a condition called nitrogen narcosis. Inert gases build in the body when Soldiers operate at 130 feet below the surface in scuba gear or as deep as 190 feet in surface-supplied diving. The anesthetics of these gases at high pressure can cause what divers call the "martini effect."

"The deeper you go past 100 feet," Kneipp said. "The more of a 'tipsy' feeling you get."

Soldiers must rise ascend slowly, or they can potentially suffer an embolism or serious decompression sickness.

Since Army divers began performing missions as part of special operations units in World War II, the instructors claim not a single diver has died in a mission-related accident, instructors said. There have been some close calls. Divers have suffered embolisms, or a blockage in their blood vessels.

Divers often must perform salvage off a sunken vessel. The skeleton vessels on an ocean's sandy bottom, can be a potential death trap. Sharp edges from the wreckage can puncture a diver's umbilical cord and breathing source.

"There really is just an endless list of things that could go wrong," said Staff Sgt. David Craig, a diving instructor. "The sheer weight of the water -- the depths of the water, drowning all of these things (are) a factor and could potentially harm the diver."

Olinger and Pfc. Nolan Hurrish do not plan on being the first fatalities. They, along with a handful of other Soldiers, and Navy and Coast Guard students, have overcome enough to make it to Phase III, the last step in becoming a certified military diver.

THE CANDIDATES

Hurrish had made a decent living for himself in central Wisconsin. He worked a laborer at a power pump factory next to a paper mill in his hometown of Stevens Point, a small community settled on the banks of the Wisconsin River.

At night, he fished along the river with friends, or travelled to one of the Badger State's many lakes. He would sit for hours on fishing boats in the evening twilight.

"I liked being around the water," Hurrish said.

He also enjoyed the outdoors and playing sports. A quarterback for Stevens Point High's football team, he had grown up working out with teammates in the summer sun. He began CrossFit training as a teenager and knew the discipline it took to develop a strict workout routine.

Hurrish, though, could not shake the feeling something was missing. He needed a change, so he talked to his local recruiter to find a career that could test him.

"I wanted a challenge coming into the Army," he said. "And I kind of wanted to set myself apart from the average (Soldier)."

He found that challenge and perhaps more when he arrived for Phase I of the Army Engineer Dive School at Fort Leonard Wood in the middle of a scorching summer in Missouri.

With spiked brown hair, his face flushes red in the summer heat. But he carries a calm confidence about him. Hurrish entered Phase I with some fortunate advantages. At 6 feet and 160 pounds, his experience as an athlete helped him get in shape for the strenuous hours underwater.

He arrived at Leonard Wood a month early, sitting poolside, watching two classes struggle and wither through the course. He took mental notes as he waited for his turn to begin the training.

A meticulous student, Hurrish could process information and learn exercises quickly, a skill possibly developed during his days as a signal caller on the gridiron.

His path would eventually converge with Olinger's, another new Soldier who arrived a few months before.

Hurrish had plenty of experience fishing above water. But swimming underneath it presented a whole different challenge. The most difficult came in the heavy underwater problem-solving block of the training.

Instructors ask diving candidates to swim along the bottom of the pool in their snorkel equipment. At any moment, a master diver instructor will swoop toward the student and pull off his diving mask and snorkel. Then the instructor will spin the student twice to simulate the disorienting atmosphere of an ocean or river.

The students must locate their equipment and finally tap the end of the lane line. Students must achieve all this in a single breath while remaining calm.

During this event, Hurrish said, he realized that he could pass the course.

"Once you start to change your attitude and how you think under the water," he said, "it becomes more bearable and you increase your confidence really fast."

Olinger had more worldly experiences than many of his peers. At just 20, he occasionally rambles, still resembling a teenager. But at other moments he speaks with an articulate sensitivity beyond his years.

He grew up in a military family and his uncle, Mike Shay, joined the Army's combat engineer ranks. Seven of Olinger's cousins also served in the armed forces.

Olinger attended a high school in China where he learned to interact with other cultures at an early age. He moved there with his mother who worked as a teacher at international academic institutions. He later moved to Wyoming, where he enjoyed going to the lake in the summertime with friends. Olinger took swimming lessons as a child and enjoyed playing watersports.

He joined the Army at 19. "I wanted to get (a career) that would change me," Olinger said.

That experience gave Olinger a confidence that he exudes when approaching training during Phase II in Panama City. Phase I in Leonard Wood tested that swagger.

During a Phase I exercise known as "aquatic adaptability," Olinger and his classmates faced a swimming endurance challenge. During the exercise, students must swim 500 yards in a single breath.

"It was brutal," he said. "I didn't think it was ever going to end."

Olinger ran on cross country and track teams in high school and understood how to pace himself to the rhythms of his heartbeat. He knew his limits. Engineer diver training at Panama City and Leonard Wood pushed him beyond them.

He spent extra hours doing pushups and pull-ups as night fell, while other students had already retreated to their rooms in the barracks.

"I can remember a lot of days, a lot of times when we would be doing over unders (exercises swimming the length of the pool at the bottom)," he said. "I (came) up on the other side and I was like 'this is the one, I'm done. I'm quitting. I'm quitting.'

"But I just sat there and waited. I caught my breath. You just delay it and delay it; finally just get to the point where you're like 'you know, I can keep doing this.'"

NATURE THROWS A CURVEBALL

In an odd twist of fate, just a month into their training in Panama City, Hurricane Michael ripped through the Florida panhandle, causing catastrophic damage to parts of the city and its surrounding communities.

The unpredictable weather forced the students and instructors to adjust to the elements, similar to a diver working in the field.

For more than a month, classes halted. Phase II students spent their time helping residents, cleaning debris and helping those whom the storm displaced.

When classes resumed after the Thanksgiving holiday, instructors chose to restructure the course in tighter blocks. Students had to learn their exercises quickly; to get it right in a day instead of two or three.

By the time Hurrish and his fellow students finish training, they will be skilled at welding, construction and making structural repairs to bridges and boats.

If the dangers of the deep seas were not enough, divers risk electrocution during every cutting and welding dive. Electricity in saltwater can be a deadly mix. Using a hand-held torch-like device called a "stinger" controlled by the diver, and circuit breaker on surface, electric current is sent from above down to the diver. For up to 30 seconds, this torch burns at 10,000 degrees.

Gases from the exhaust of burning these rods can accumulate underwater, creating air pockets making oxygen explosions a serious safety hazard caused by the smallest spark.

During a deployment to Kuwait, Kneipp experienced one such explosion firsthand. The strong force ruptured one of his teeth.

"It was like a mule-kick in my chest," he said.

FINAL STEP

Army engineer divers perhaps delve into places few will ever see, whether on an excavation of a shipwreck or searching for veteran remains in the waters of the South China Sea. Before graduation later next month, Army divers must pass one final certification. They begin a six-week block where they learn the intricacies of underwater demolition and learn how to set and detonate charges in maritime conditions.

After Hollinger and Hurrish survived the first four weeks, their odds of passing the phase significantly increased. Instructors estimate 85 percent of students pass the course after they pass the trials at Leonard Wood and the high-stress, initial weeks at Panama City.

If Olinger and his dive school classmates survive Phase III, they will join an exclusive Army diving force.

"I've waited this long and I've put out this long," Olinger said. "So I'm not going to quit now."

(Editor's note: This is part two of a two-part series on the Army's engineer diver training. For part one, visit www.army.mil/article/217444 or see the link in the related links below.)