Two San Diego men adrift in a lifeboat for nearly six hours were rescued by a passing sailboat Tuesday after their trawler, the Dana Reberta, sank off the Coronado Islands. Coast Guard Lt. Claudia Wells said Robert L. Ashbore and Randy E. Modisett, ages unknown, were on a diving expedition when their trawler began taking on water about 8:30 a.m. The vessel sank 1 1/2 hours later, and the men got in the trawler's lifeboat. They were picked up about 3:40 p.m. by the crew of the sailboat Fairwind, whose home port was not immediately known. Ashbore and Modisett were uninjured, Wells said.