The men, all in their early 30s, were from Spanish Fork, American Fork, Orem, West Jordan and South Jordan. They had launched their 18-foot, open-bow trihull fishing boat with an inboard motor from American Fork boat harbor about 4:30 p.m., Harris said.

They were headed for Bird's Island. They had about nine life vests on board, he said.

About 5:45 p.m., the boat was between the American Fork and Provo boat harbors when the men said they saw a large wave coming from behind the vessel. Four of the men ran to the back of the boat to try to balance it, but another wave came over the bow, said Utah County Sheriff's Sgt. Tom Hodgson.

Deputies who were later called to the scene reported seeing 3- to 4-foot swells.

Most of the six men were able to grab a life vest or seat cushion. Three of the men stayed with the boat for about 30 minutes, including Thongthipvoravong, before deciding to swim to shore, Hodgson said.

Thongthipvoravong was struggling during the swim, according to what the survivors told the sheriff's office, Hodgson said.

After spending three hours in the lake, Joe Rajsavong, 31, was the first to swim to shore, and he called 911.

"A boat sank, and I've got five friends out there. … I can't find them. I barely got on shore and went back to the golf course," he said in the recording obtained by the Deseret News.

"Were you out there, or they just called and told you?" a dispatcher asked.

"I was out there with them."

"And you swam back?"

"Yeah. It was like a good three hours ago."

"So there's five friends that are unaccounted for?"

"Yes, I can't find them right now. We all had life vests."

During the call, Rajsavong requested medical assistance, saying he was cold. "My whole body is cramping," he said.

"Did you see which direction they swam from you?" the dispatcher later asked.

"We were going the same direction, but the other three were way behind us. … I couldn't find the others."

"When you got out, you couldn't see anybody else?"

"No."

"OK. Were the waves pretty bad?"

"Yeah."

Search crews Tuesday took Boukithanth Saengkeo, 33, of Spanish Fork, back onto the lake to have him show them where the boat sank. Ten boats, three helicopters and an airplane have assisted about 65 searchers from at least six agencies in the rescue effort.

The Utah Department of Public Safety's sonar boat, which was used recently in the search for a missing 8-year-old boy in a Jordan River surplus canal, was not available for the Utah Lake search. Officials from the Arizona Department of Public Safety had requested use of the boat in recent days to help with a homicide case in their state, according to the Utah department.