Responders worked to secure diesel oil spilled from a tugboat that sank in its moorings Tuesday and was 120 feet underwater Thursday afternoon in Wrangell, the Coast Guard said.
The vessel Silver Bay II was moored at the Wrangell Silver Bay logging sawmill along Zimovia Strait near the Southeast Alaska community of Wrangell when it sank, U.S. Coast Guard Chief Petty Officer Sara Mooers said.
The incident was discovered around 3 p.m. Tuesday as Silver Bay employees conducted a check of the docks and boats, according to a release sent out by the Alaska Department of Environmental Conservation (ADEC).
The Silver Bay II is a 60-foot steel-hulled tugboat, previously used for commercial purposes and now a recreational vessel. The vessel had been tied to the dock for the past five years, a Silver Bay representative told the ADEC.
On-scene responders reported that the ship drifted under a deck barge when it sank.
Nobody was onboard when the ship sank, according to the Coast Guard. The vessel had an estimated 3,500 gallons of diesel on board, the ship's owner told the Coast Guard. Why it sank is unknown, Mooers said.
Silver Bay employees put a containment boom around the vessel, but the boom doesn't adequately contain the sheen, according to the ADEC. Silver Bay was directed to deploy additional containment on Thursday. A sheen extending five miles from the sunken vessel was spotted by Coast Guard pollution investigators during an overflight on Wednesday. However, "it's impossible to tell from a sheen" how much fuel has leaked, Mooers said. Small amounts of oil were observed rising to the surface on Thursday morning, the ADEC writes.
Alaska Commercial Divers was called in to assist by the vessel's owner, but flights to Wrangell were delayed due to weather on Thursday. Winds up to 28 mph and heavy rain were reported with a gale warning in place.
Once divers reach the vessel, they'll cap the fuel tanks and assess damage to the vessel.
The Coast Guard was on site Thursday with vessel's owner as the Alaska Department of Environment Conservation worked to develop a response plan. No impacts to wildlife or subsistence resources have been reported.