Another boat fire was put out quickly in a harbor in Petersburg Thursday morning.

The Carolyn Ann, tied up to the A Float in Petersburg’s South Harbor, was reported on fire by harbor staff. Petersburg Volunteer Fire Department spokesman Dave Berg said harbor staff knocked down the fire on the outside of the vessel with an extinguisher.

“Without them having spotted it, I’m sure the damage would have been much greater,” Berg said. “The volunteer fire department responded with two engines and officers who boarded the vessel, fire fighters boarded the vessel and followed up on hot spots in the engine room and in the interior of the house of the vessel, in some of the void spaces, extinguishing what was left of the fire.”

Volunteers were on scene about 25 minutes. Berg said the blaze is still under investigation but fire fighters have an idea of the cause.

“We strongly suspect that there was a short in the connection where the shore power comes in connection to the vessel,” Berg said. “The fire started right there at that plug and that can typically be an area that we see lots of times that deals with the failure of those electrical connections getting hot corroded and eventually bursting into flames because of the heat that’s generated in the transmission of the electrical when there’s a loose connection. So we certainly urge people to check their electrical connections, especially this time of year.”

Berg said people should check their extension cords for Christmas trees and lights with hot plugs, a sign they’re handling too much current or are damaged and should be replaced. It’s the third boat fire in the past three months in Petersburg’s harbors.