A father and son badly burned in a Naples boat explosion late Friday continue to improve at Tampa General Hospital.
Helmut Sempf, 59, remains in serious condition in the intensive care unit but is improving, according to a hospital spokeswoman. His son, 11-year-old Kristoff Sempf, has been upgraded to fair condition. The Lake Park Elementary School student suffered burns to his lower legs.
The explosion appears accidental. Helmut Sempf was trying to remove gasoline from the boat when a spark caused the blast, fire officials said.