A Coast Guard official who flew over a petroleum drilling ship grounded on a remote Alaska island says there are still no signs of any fuel sheen or environmental impact and the rig appears to be stable.

The Royal Dutch Shell PLC drill ship Kulluk (CULL'-uck) ran aground in a fierce North Pacific storm Monday night off an uninhabited island near Kodiak.

Calmer weather conditions Wednesday also allowed a team of five salvage experts to be lowered by helicopter to the rig to conduct a three-hour structural assessment. Officials say their information will be used to formulate salvage plans. Also taken to the Kulluk was a state-owned emergency towing system for use in the operation.

Coast Guard Capt. Paul Mehler (MAIL-er) says he saw four life boats on the shoreline but there was no indication that other debris had been ripped from the ship.