An early morning fire at Silver Lake Marina on Grapevine Lake damaged six boats, destroying three.
Grapevine firefighters received a call about the fire on the marina just before 4 a.m. Friday.
"There was actually someone asleep on their boat and heard the cracking and popping of the boat on fire and woke up and gave us a call," Deputy Fire Chief Kent Short said.
Short said crews dragged three of the boats away form the dock to avoid further damage to other boats. Two of the burning boats sank in 25 to 30 feet of water.
Short said there was a breeze that could have spread the fire. Three other boats near the burning vessels were damaged.
Short also said that investigators aren't sure what caused the fire. Arson has not been ruled out.
"We've sprayed it with a lot of water and it's half submerged as it is right now, so as far as dogs coming out to sniff, it probably won't do us much good," he said. "But there is other means and tools to check on that."
Investigators are reviewing surveillance video from the marina to check for suspicious activity.