Multiple law enforcement agencies responded at about 3:50 a.m. to the marina for a report of a fire, said Lt. Terri Millefoglie, spokeswoman for Indiana Department of Natural Resources' law enforcement division.
A preliminary investigation showed one docked boat caught fire before the blaze spread to another in the G dock section of the marina, near the main office, Millefoglie said.
Two boats are considered total losses, she said, and two others suffered some level of damage. Investigators believe an explosion on the first boat triggered the second boat to catch fire.
The police and fire departments of Hammond, along with the U.S. Coast Guard, Hammond Port Authority, Hammond Marina, and Tow Boat U.S., all assisted at the scene, Millefoglie said.
At this time, there have been no injuries reported. Hammond fire officials are investigating the fire.
The cause remains under investigation.