* Oil rig refloated at 0710 GMT
* Weather remains a challenge, with gales forecast
* Salvage teams found no signs of breaches to fuel tanks
By Yereth Rosen
ANCHORAGE, Alaska, Jan 7 (Reuters) - A recovery team has refloated a Shell oil drilling rig that ran aground last week near an Alaska island and stands ready to start towing it on Monday, weather permitting.
The saucer-shaped Kulluk drillship, wrestled from the ships towing it by near-hurricane weather and tossed onto the shore, was refloated at 1010 PM on Sunday night (0710 GMT Monday) after a tow line was attached, a statement from the joint command center for the Kulluk responders said.
Weather in the area remains a challenge, with the National Weather Service issuing a gale warning through Sunday night and forecasting rain, snow and winds of between 15 and 30 miles an hour.
The fortunes of the Kulluk, which started drilling a well in the Beaufort Sea late last year, face particular scrutiny because it was a major part of Shell's controversial and error-prone 2012 Arctic drilling program.
The U.S. Coast Guard and Royal Dutch Shell Plc hope the rig can be towed from its grounding site on the coast of tiny Sitkalidak Island to a sheltered bay nearby, so experts can make a better assessment of its sea worthiness.
"Following this initial step forward, we will continue to remain cautious while we assess the Kulluk's condition," said Martin Padilla, incident commander for the Kulluk responders. "We will not move forward to the next phase until we are confident that we can safely transport the vessel."
Sean Churchfield, Shell's Alaska ventures manager, has said salvage teams found no signs of breaches to any of the Kulluk's fuel tanks and only one area where seawater leaked onboard. The tow plan has been approved by government regulators.
Coast Guard Captain Paul Mehler had said the right combination of tides and weather, as well as the arrival of certain equipment, was required to begin towing.
The Kulluk went aground in a storm on Dec. 31 after the ship towing it lost power and its tow connection in the Kodiak archipelago, far from where it began its well in September and October.
The rig had been headed for winter maintenance near Seattle.
The removal plan is to pull the Kulluk about 30 miles to Kiliuda Bay, a site previously designated as a refuge for disabled vessels. Whether it continues on for its maintenance work will be determined after the assessment, Churchfield said.
The rig has about 155,000 gallons of diesel fuel and other petroleum products aboard, none of which have spilled, state environmental regulators said.
The Aiviq, the vessel that lost power and its tow connection to the Kulluk a week ago, is the ship designated to tow it to safe refuge. An investigation into its failures is not yet complete, Churchfield said.
Alaska environmentalist Rick Steiner questioned Shell's reliance on the Aiviq and said he believed the problems with the Kulluk and its other contracted drillship, the Noble Corp -owned Discoverer, would preclude any drilling this year. "The 2013 season is on the rocks in Kodiak with the Kulluk," he said.
Shell officials in Alaska have so far declined to comment on the upcoming Arctic drilling season.
Prior to the Kulluk accident, Shell's main problem in Alaska was the Discoverer, which had been assigned to Chukchi Sea work but failed to meet federal air standards, prompting Shell in June to ask the Environmental Protection Agency for a permit with looser limits for air pollution.
In September, the ship dragged its anchor in the Aleutian port of Dutch Harbor and nearly grounded on the beach there.
After completing a truncated 2012 drill season in the Chukchi, the Discoverer was temporarily detained by the Coast Guard in the port of Seward, Alaska. The Coast Guard cited numerous safety and environmental-systems deficiencies, which Shell and Noble vowed to fix before the summer season began.