The hallucinations begin, typically, after Forrest Nelson has been in the open water for nearly 24 hours, after he has been swimming for about 20 miles.
The escort boat, that includes support personnel for the long-distance swimmer, transforms into a pirate's ship with all the neat fixins.
"Something out of Pirates of the Caribbean,'' Nelson said. "Tall masts and tattered sails and all of it a blood orange color.''
As for the people on the support boat, Nelson can't remember if they turn into pirates. But if they do, he says, it just makes for a better out-of-body experience.
Swimming long distances is nothing new for Nelson, who was a member of the Wichita Swim Club and attended Southeast High while growing up. His most recent accomplishment was a 48-mile swim around Catalina Island, 22 miles off the California coast near his current home, Los Angeles. It took him 25 1/2 hours and tested his physical and emotional limits. A pirate ship was the least of his problems.
Nelson, 46, swam the English Channel in 2005 and the Cook Strait crossing in New Zealand, a trip that covered only 16 miles only, I say and 12 hours but, Nelson said, might have been his most difficult swim every because of strong winds.
In the summer of 2010 he swam the 22 miles from Catalina Island to the California shore and then back to the island, which lasted 23 hours.
All this from a guy who says he was far from being an honor swimmer during his days at the Wichita Swim Club, where he started when he was 7.
"I'm not a bad swimmer,'' Nelson said, "but I'm not a great swimmer, either. There are swimmers from the WSC who have done some really incredible things in college. I'm not one of them. I didn't even swim in college. I was never even close to being the fastest swimmer on my team in those Wichita days.''
But all of those kids who zoomed ahead of Nelson in the pool back then would be amazed at the things he's doing in the water now.
"My swimming friends get it, to a point,'' said Nelson, who works for Clear Channel, a major radio corporation. "They understand my joy of swimming. Now why I want to do it for an entire day at a time in some cases is a little more difficult to explain.''
Even to himself. Nelson never imagined he would become an open-water swimmer of long distances. Like everyone, he heard about people swimming the English Channel when he was a kid. And like almost everyone, he never imagined being one of them.
"The Catalina Channel, as an example, has been crossed by a few more than 200 people,'' Nelson said. "The English Channel by a few more than 1,000. And the histories of both of those channels go back about 100 years.''
Nelson has the make-up of an ultra-marathoner or other athletes who push themselves to extremes.
"You come out of the water after one of these swims and you're absolutely exhausted,'' Nelson said. "The next few days you try to sleep a lot.''
But then it's back to training, which becomes an obsession for Nelson and others like him. There's so much pain involved with getting a body ready for 20, 30 and 40-mile swims.
"I do love swimming and as an adult I got back into it as a form of exercise and recreation,'' Nelson said.
Then it turned into something else. It's not enough for Nelson to go to the YMCA and swim a few laps during the lunch hour.
He says he loves the outdoors and that as a kid growing up in Wichita he and his family did what they could to avoid being enclosed.
Swimming has been beneficial for Nelson in many ways, health being at the top of the list. It also has allowed him to see parts of the world he wouldn't otherwise have gotten to see.
His bucket list includes a swim across one of the Great Lakes, most likely Ontario. That's a 30-mile swim from western New York to Toronto.
"I would also like to swim Gibraltar, which would actually be a swim between continents,'' he said. "It's only eight miles between Portugal and Morocco but eight extremely challenging miles because of wind and current and a great deal of boat traffic.''
No, they don't shut down these waterways for people who want to swim across them. So boats are a real danger.
"It's kind of like the video game Frogger,'' Nelson said. "You're a swimmer out there trying to cross a difficult path.''
Water temperatures almost always cold are another issue, Nelson said. They range most often from the low 60s to the upper 60s.
"Within a short period of time people can become hypothermic,'' Nelson said. "Which taken to the extreme can be lethal.''
It's those people in the escort boat the pirate ship that make sure nothing bad happens to Nelson during one of his swims. But they can't control what goes on in his mind as he approaches 20 miles and 24 hours in the water. That's where the really scary stuff happens.
"I hear from ultra runners who say those hallucinations are part of the joy when they're off running in the middle of the night,'' Nelson said. "It's a distraction. In a healthy way, of course. I was in a great deal of pain and my shoulder was really acting up on me when I saw the pirate ship. That took me away from the pain and helped me focus on something brand new.''