Mystic — Firefighters on Monday extinguished a stubborn, smoldering fire inside the 70-foot Italian yacht, Blue C, which was docked at the Seaport Marine.

The fire was reported about 9 a.m. and Mystic Fire Chief Fritz Hilbert said it was in an area between the engine room ceiling and the deck above, making it difficult to access. Firefighters had to move equipment and cut holes in the deck to get to the source.

Firefighters from the Mystic Fire Department were on scene for several hours and able to stop the spread of the fire and limit damage to the boat, Hilbert said. Manpower was called in from the Old Mystic Fire Department.

Hilbert, who also is the fire marshal, said the cause of the fire remained under investigation but appeared to be related to the electrical wiring and the exhaust that runs between the engine room ceiling and deck.