Four people were pulled from Casco Bay after their sailboat overturned in a squall Saturday afternoon. John Tracy, captain of the Casco Bay Lines ferry Aucocisco, said he spotted the small boat about 4:30 p.m., shortly before heading off on a run from Portland to Great and Little Diamond islands. He said the sailboat was between Little Diamond and House islands when the storm came up. A rescue boat approaches an overturned boat in Casco Bay after a brief storm on Saturday. “It got real dark over Portland, so we knew we were going to get hit,” Tracy said. The small sailboat flipped over in a gust, pitching the four people aboard into the water, Tracy said, and he stopped his ferry and tried to position it near the people in the water. “It was blowing so hard I was side-to the wind,” Tracy said.