SAN FRANCISCO (CBS SF) — A 34-foot fishing vessel sank in its slip while tied up at the Hyde Street Pier on San Francisco’s northern waterfront early Wednesday morning.

The ship sank at some point around 3 a.m. The U.S. Coast Guard was called out to the scene hours later. So far, there is no word as to why the vessel sank.

The boat holds a maximum capacity of 260 gallons of diesel, but crew members believe there was much less than that left.

An oil sheen was observed around the ship. Three layers of containment boom and absorbent pads were placed around the vessel to prevent it from spreading, according to the U.S. Coast Guard.

The Port of San Francisco also tweeted about the vessel, identifying it as the Island Cove out of Moss Landing. At t

One person was on board when the boat started taking on water around 3 a.m.

“At some point in the middle of the night, the occupant and operator heard a noise,” said Randy Quezada with the Port of San Francisco. “He goes out to investigate and saw that the vessel was taking on water and then gets off and notifies the authorities.”

Quezada said that within 12 hours, crews were able to make the situation safe.

Port officials noted that the Department of Fish and Wildlife was also involved in the spill containment. Officials also said salvage teams are on-site and will begin working to raise the vessel.