The APL Panama became grounded Dec. 25, 2005 as it prepared to enter the port of Ensenada. It was on a regularly scheduled trans-Pacific route that led from Oakland to Mexico, then Japan, Taiwan and China. Pushed by surf and hemmed in by sand, the vessel had become increasingly stuck. The challenge has been daunting. The vessel, which weighs about 15,000 tons, is carrying nearly 30,000 tons of cargo. Seven tugboats pulling at full force yesterday morning � a combined capacity of more than 80,000 horsepower � moved the bow a few more yards away from shore, and they are expected to repeat their efforts today. "The principle is that very slowly, as she rolls, each time she displaces sand, the tugs pull, the ship is moved so it occupies that space," said Michael Mallin, an attorney for Titan and its parent company, Crowley Maritime Corp.