Authorities are searching for one of two fishermen who were aboard a 42-foot scallop boat that sank about two miles north of Provincetown on Sunday. The “Twinlights” vessel capsized at about 11:30 a.m. in an area where the water’s depth reaches about 190 feet, United States Coast Guard Petty Officer Robert Simpson said Sunday afternoon. The boat is believed to have become entangled in fishing gear, causing it to sink, he said. One man, who is believed to have been on the deck of the boat when it sank, was rescued by a nearby lobster boat called the “Glutton,” which called the Coast Guard to tell them about the sinking boat, Simpson said. Another man, who is believed to have been inside the pilot house of the boat that sunk, has not been found, he said.