Firefighters were called out to the Grand Marina in Alameda about noon on Thursday to help put out a fire on a 30-foot sailboat, where a man was burned and flown to a hospital.
Division Chief Doug Long said when firefighters were told by dock workers and witnesses that a person may still be on the boat.
LOng said before the firefighters could get to the boat, the man was able to jump into the water to extinguish the flames. A relative of his then pulled him out of the water.
The man was taken by helicopter to to Santa Clara Valley Medical Center with burns over 20 percent of his body.