HOUSTON >> For hours after their boat sank, Ken Henderson and Ed Coen treaded water in the Gulf of Mexico, talking about life and death while struggling to survive. For more than 30 hours, it worked.

Then Henderson was forced to make a decision that would save his life, but not his best friend’s.

"This is the last-ditch effort, but I’m going to go for help or you’re not going to make it," Henderson told Coen, just before cutting the strap that connected them in the deep, cold waters off the Texas coast.

"I understand," Coen responded, giving Henderson a last set of instructions. "Kiss them babies for me."

It was Friday around 4 p.m. when they parted.

On Tuesday, days after the fishing trip ended in tragedy, Henderson recounted the harrowing tale for The Associated Press, alternating between sorrow, guilt and laughter as he recalled the last 30 hours of a man who had been his best friend for 25 years.

The saga began Thursday around noon. They had been fishing for a few hours when Coen noticed the 30-foot Scarab was filling with water. Henderson started four bilge pumps. Water sprayed everywhere.

Coen quickly unhooked the boat from one of the many oil and gas rigs in area where they had been fishing. Henderson revved an engine, but the saltwater that had leaked in kill them quickly.

"Mayday, mayday, mayday Marine 16," Henderson called over his Marine radio. He got no response.

He dialed 9-1-1 on his cellphone. There was no signal.

Suddenly, the bow went up. Henderson flew back. Coen jumped to the right, his sunglasses and cap flying off. Already wearing life jackets, the two ex-Marines grabbed extra life jackets and other floating items.

"The water was so cold it took your breath away," Henderson said.

Coen, a slim man, immediately began to shiver.

After failing to swim to a gas well nearby, the pair prepared for a long wait.

And they talked.

"We talked about stuff that I’ll never talk about. We discussed things and discussed life. We discussed families. We just tried to keep ourselves occupied," Henderson said.

As night fell, they took turns laying on each other’s chests, conserving body heat. They tied their life jackets together to ensure they wouldn’t drift apart in the dark.

They dozed. Coen started hallucinating. Henderson tried to keep Coen’s arms and legs moving. He called him a sissy to get him angry. But as morning came, Coen’s situation worsened. It took time to wake up. He tried to light a cigarette that wasn’t in his mouth.

"I came to the realization that one of us may not make it or that both of us may not make it," Henderson said. "I just felt helpless sitting there with him."

About 3 p.m., the pair drifted toward a manned rig. Henderson realized his friend wasn’t keeping his head above water.

Henderson told Coen to kick to the rig. He pulled him as he swam, but Coen was sideways. Henderson told him to kick. Coen thought he was.

And so Henderson decided to cut the strap.

He swam for two hours, but lost his sense of direction. He was tired. Frustrated. Depressed. He rolled on his back and floated. It was after 7 p.m. when he woke up.

He saw another rig in the distance, and prayed for strength.

He swam, seeing ice and crystal trees in the water. He reminded himself constantly there were no trees. He made it past a blinking light, a milestone that pushed him on toward the rig.

It was 2 a.m.

On legs so weak he could barely lift them, Henderson slowly pulled himself up the rig’s barnacle-covered ladder.

"I’m here. I’m on a derrick," Henderson said out loud.

He found a galley with food, water and a phone. He called his wife, and told her to call the Coast Guard. He said he was on rig 633A.

"It was over 50 miles from where we went in the water," Henderson said.

All he could think of, though, was Coen. Convinced his friend would survive, he told the Coast Guard where they had parted.

Two hours later, Henderson was ashore in the Coast Guard dispatch room when haunting words came across the radio. A fisherman had found a body in a life jacket.

Later, in the hospital, Henderson saw his friend. He apologized and asked for forgiveness. He promised to fulfill his wishes, make him proud and look after his girls.

"I felt like a part of me had died out there," Henderson said.