When Josh Collins is on dry land, he feels like he’s at sea. Walls move, as if they are rolling in the waves. Floors tilt, as if they are the deck of boat.

During seven deployments to Bosnia, Afghanistan and Iraq, Collins, a former U.S. Army Delta Force captain, sustained injuries to his brain, spine, inner ear and eyes that cause chronic balance and vision problems.

When Collins was undergoing therapy two years ago, his wife bought him a paddleboard. The first time he tried it, he got his equilibrium back. He discovered that when he is on the water, he feels like he’s on dry land.

“My world is always shifting, like I’m a sailor,” he said. “But when I’m on the board, everything holds still. The horizon is stable. I’m in rhythm with the motion of floating and paddling. It’s my sanctuary.”

Paddleboarding not only became Collins’ passion but also a means of coping with the lingering damage from traumatic brain injury and post-traumatic stress disorder, ending his dependency on prescription medications and alcohol, and eliminating suicidal thoughts.

After years of special operations combating terrorism, Collins has embarked on a new mission as a veteran. He intends to set a world record by stand-up paddleboarding 3,500 miles from Corpus Christi, Texas, to New York City. He’s approaching the halfway point in his five-month voyage as he travels north along the South Florida coastline. Keep an eye out for the solo paddler wearing an olive-green hat atop a camouflage-colored, 14-foot Bote board.

Collins, 46, is on a journey of self-discovery after nearly losing his mind. Eight concussions during his career — most caused by bomb blasts — changed him.

While paddling through the bayous of Louisiana and down the Gulf Coast of Florida, Collins has had plenty of time to think.

“Out there, you can scream and nobody can hear you,” he said. “I’m figuring out who I am today because I’m not the same person I was. I’m trying to quiet the storm in my head and sort through the mess. It’s like putting a puzzle together, but all the pieces are marbles.”

He’s not doing it to be a hero, because there’s not much glory attached to paddling 10 to 14 hours per day, an average of 30 to 40 miles if the wind and current don’t reduce his progress to a crawl. His feet are wet. His shoulders hurt. His skin is glazed with sunscreen, sweat and saltwater.

He’s got a cooler with food and water on the board — he’s constantly munching on trail mix — plus an extra paddle, VHF radio, GPS, personal locator beacons, rain suit and first-aid kits (there were rattlesnakes on the beaches in Texas). He flies two flags — the Stars and Stripes and one with the logo of the Task Force Dagger Foundation, which supports special operations veterans.

Collins is usually alone, except for the curious alligators, sharks, manatees and dolphins that have accompanied him here and there. Kayakers and other paddleboarders have joined him for stretches, and the Coast Guard escorted him through shipping lanes near Houston. People have come out on boats and docks to offer him food or a warm bed.

His wife, Tonia, drives parallel to his route in their small RV, meeting him at accessible checkpoints and picking him up at the end of each leg. They spend their nights at campgrounds.

Collins is planning a detour 120 miles upstream on the Potomac River into Washington for a rally, and he anticipates those as his most grueling days.

His goal is to paddle past the Statue of Liberty and finish at New York City’s Battery Park on July 23.

Collins enlisted in the Army in 1988 and was stationed at Fort Bragg, N.C., with the 82nd Airborne Division. He was on the Army’s boxing team. He fought in Desert Storm. He became an Army Ranger, then joined the elite Delta Force.

Throughout his tours of duty, he sustained head trauma on parachute landing falls and from the blast waves of explosions.

Collins’ first wife died of leukemia in 2005, and he was a single father of their two children. He married Tonia, who had two kids of her own, before he retired from the Army in 2008. After he sustained a ninth concussion in a fall at home three years ago, symptoms of brain injury got much worse.

“I was Dr. Jekyll and Mr. Hyde,” he said. “I’d wake up at 3 a.m. to a dozen medications and a bottle of wine and kept drinking throughout the day. Functional insanity. I’d get lost driving home. I had panic attacks, which was bizarre for a special ops warrior like me.”

Tonia, who was running a brew pub at the time, described Collins as “aggressive, angry, depressed, anti-social and suicidal.”

Tonia admitted him into the Tampa VA Hospital’s Polytrauma Rehab Center, where he spent three months.

“That saved his life, but then we had to get him off all the medications that made him a zombie, like so many of our veterans who get buried under prescription drugs,” she said.

They sought guidance from the Task Force Dagger Foundation and found alternate forms of treatment from brain trauma specialists in Dallas and Long Beach, California. They are spreading the word, and lobbying for more research on injury and prevention by the military. He’s getting a service dog, Charlie, who can aid him with balance.

Paddleboarding was Collins’ favorite therapy. The world-record trek seemed like a dramatic way to call attention to the plight of veterans and their will to recover. He also dreams of completing a world-record row around the world.

“Josh’s new energy and focus amazes me,” Tonia said. “He’s putting it all on the line, like he did in the war, because this is for the bigger purpose of helping others who are suffering.”

Follow Josh Collins' journey, including GoPro videos, on his Facebook page, Veteran Voyage 360, or website, veteranvoyage360.com.