The Jacksonville men were fishing more than 60 miles east of St. Augustine on Sunday when there was an explosion in the engine compartment of the 25-foot vessel, Navy and Coast Guard officials said.
``We didn't even have time to grab life preservers or make a distress call,'' said John Porcella.
The crew of a shrimp boat saw the smoke and contacted the Coast Guard.
Porcella said he and boat owner James Cooksey Jr., 59, clung to each other's shirts and tread water for about two hours until Navy helicopters arrived from the aircraft carrier George Washington, which was on maneuvers in the area.
Porcella said they became separated when the helicopters kicked up waves. When Porcella found his friend again, Cooksey was unconscious. Cooksey died of cardiac arrest, the Duval County Medical Examiner's office said.
The four survivors were treated aboard the George Washington for mild hypothermia and second-degree burns.