A sunken boat will need to be salvaged after going down in Lake Macquarie on Saturday.
Marine Rescue was alerted that a vessel was sinking in waters off Valentine, with crews immediately springing into action.
One rescue boat and a jetski were dispatched from the base and responded to the incident.
Upon arrival, crews found that the craft was at anchor and completely below the waterline with no one onboard.
It is currently not known what caused the vessel to become submerged.
A spokesperson for Lake Macquarie Marine Rescue said NSW Maratime would be notified and the owner tracked down before salvage efforts commenced.