The company said the incident involving the 48,000-dwt Pacific Quartz (built 2011) happened on 3 October as it was heading into port with a pilot on board.
It touched the seabed near its No 6 starboard water ballast tank.
No pollution was reported and the crew was unhurt.
The tanker was carrying 34,821 tonnes of diesel at the time.
In a later update, the manager said the vessel berthed the same day after initially anchoring.
Divers
