The suit seeks unspecified damages for negligence.
"They would hope that their boy's death was not in vain, and that no other family will have to suffer the same type of tragedy," the family's attorney Mike Neil said.
Neil says the Coast Guard vessel was traveling 35 to 46 mph during the crowded San Diego Bay Parade of Lights Dec. 20. He says the Coast Guard was apparently not on a rescue mission.
The U.S. Attorney's office, which will defend the government, had no comment on the lawsuit. The Coast Guard did not return our phone call.