The 103,000-dwt Minerva Iris (built 2004) ran aground Monday in the Houston Ship Channel but was quickly freed with the help of three tugs.
A US Coast Guard official tells TradeWinds that the investigation into the incident is trying to determine whether the charted depth of the channel is correct.
Click here to see a WebTV story on the grounding.
Lt Tim Tighman says hurricane activity last year may have led to silt build-up in the area of the grounding.
Houston pilots have responded to the incident by temporarily reducing the maximum draft in the channel from 13.7 metres to 12.8 metres, according to shipping agency GAC.
There were no injuries in the grounding, and the Minerva Iris was undamaged. A Coast Guard overflight found no pollution.
The Greek-flag tanker is controlled by Athens-based Minerva Marine.
Minerva S&Q manager Dimitrios Stamoudis tells TradeWinds that the vessel was laden with nearly 88,900 tonnes of fuel oil at a draft of 13.7 metres when it ran aground.
The Minerva Iris was transiting the channel with the help of two pilots.
"It must be noted that immediately after the incident the authorities issued a notice to mariners by which the maximum permissible draft for passing vessels in Houston/Galveston Ship Channel was limited to 42 feet instead of 45," Stamoudis said. "At the same time [the Coast Guard] requested the United States Army Corps of Engineers to perform a thorough depth survey in the area."
After re-floating, inspections of the Minerva Iris found no deficiency, and the vessel was permitted to continue her voyage.