No one was injured, but several boats at the marina sustained major damage.
Cornelius-Lemley and Huntersville firefighters responded to the fire just after 3 a.m. Friday.
"You have a marine fire," a dispatcher can be heard telling firefighters on a recording of radio communication. "Caller is advising multiple boats on fire at a dock."
Firefighters cut nearby boats loose and quickly doused the flames with water, an act the Cornelius-Lemley Fire Department credited with preventing the fire from spreading to the marina and other boats.
The department said its firefighters train often for marina emergencies.
Neighbors with views of the the marina said the bright flames and emergency vehicle sirens woke them from their sleep.
WCNC Charlotte spoke briefly to the marina's general manager and the owner of one of the damaged boats, but both people declined to be interviewed due to the pending investigation.