The tugboat Powhatan remains underwater, surrounded by booms to contain the oil spill. (Photo courtesy of SEAPRO)A tugboat with more than 300 gallons of oil aboard sank Wednesday night in Sitka.Listen nowThe tug – owned by Samson Tug & Barge – sank near its dock in Starrigavan Bay. According to divers from Hanson Maritime Company, the tug Powhatan had drifted offshore and was found around 10:15 p.m. The divers estimate the Powhatan was 60 feet below its resting location. On board was 325 gallons of lube oil, 12 gallons of diesel, and possible sledge. It’s not known how much oil was spilled into the water.The U.S. Coast Guard, Alaska Department Environmental Conservation, and the Southeast Petroleum Response Organization responded to the scene, surrounding the tug with booms to contain the oil.The response team is monitoring impacts to wildlife, but no incidents have been detected so far.According to the state’s situation report, an underwater camera may be used to confirm the tug’s location and monitor for fuel leakage.Update: This story’s headline has been updated to reflect that 300 gallons of oil were on the tugboat, not 300 pounds. The story has also been updated to reflect the boat had sunk on Wednesday night, not Thursday.