DULUTH, Minn. (AP) _ An 85,000-gallon cargo of fuel and lubricating oil will be left aboard a grounded freighter in Lake Superior to avoid delays in attempts to free the vessel as a storm approaches, officials said.

Salvage crews prepared today to use a flotilla of tugboats in an effort to free the 584-foot Socrates from the sandy bottom of the lake, only 50 yards from shore.

''We have a possibility of getting the ship off before Friday, and it's the best gamble I've got,'' Cmdr. Stanley Spurgeon of the U.S. Coast Guard said Wednesday. ''I'm going to go with it.''

The Liberian-registered freighter was anchored Monday night awaiting a loading berth at a grain elevator when 50-mph winds and heavy seas drove it ashore on a beach a mile from downtown Duluth.

The 24 Greek and Filipino crew members were evacuated Tuesday after tugboats failed to free the ship.

Crews were eager to free the Socrates because foul weather is forecast for Friday. Another storm could damage the ship or push it farther onto the beach.

About 85,000 gallons of fuel and lubricating oil will be left aboard the ship during today's operations, Spurgeon said.

Winter cold has thickened the fuel oil, making it difficult to pump. Spurgeon said removing the oil would take at least two days, delaying the operation long enough for the approaching storm to interfere.

Commercial and Coast Guard anti-pollution crews will stand by, in case of leaks.

The ship's crew and commercial salvage workers planned to lighten the vessel today by pumping water from its ballast tanks. Once the tanks are emptied, as many as seven tugboats will be used in the attempt to drag the ship into deeper water, Spurgeon said.

If that fails, workers probably will have to dredge a channel around the ship before making another attempt, said Spurgeon, commander of the Coast Guard Marine Safety Office in Duluth.

The Socrates' owners also might have to find bigger tugboats or even use another freighter to pull their vessel free, Spurgeon said.

The grounded ship remained in good shape, its bow in 8 feet of water, the Coast Guard said. The vessel is resting in sand and listing about 6 degrees to starboard.

On Tuesday, two tugboats took a tow line from the Socrates and spent an hour straining unsuccessfully to budge the ship.

Salvage experts from the Coast Guard and private companies worked with the Socrates' crew Wednesday, preparing the ship for today's rescue effort.

An 11-member Coast Guard team from North Carolina brought a planeload of pumps and salvage equipment and will stand by in case the Coast Guard decides to take over the operation.

The Marine Safety Office has begun an investigation of why the Socrates went aground, Spurgeon said. Coast Guard officials have not speculated about what might have happened aboard the ship or whether its captain was at fault.