SAN FRANCISCO (AP)—Feder al authorities Wednesday exam ined a hatch cover, some debris, three guns and a few flecks of paint — the only evidence in the mysterious disappearance of a fishing boat and two men. The air and sea search for the Steelhead, its skipper E. A. Dave Davisson and Ted Bean, captain of another boat, the Coho II, was abandoned by the Coast Guard. “From now on it is a matter of interviewing people and studying the evidence we have recovered. The physical evidence — includ ing a hatch cover, possibly from the Steelhead, with a bullet hole in it,was at the FBI laboratory. The guns, two rifles and a shot gun, and the paint flecks were from the Coho. The mystery began Sept. 23 ,when Davisson radioed from off Monterey that he had ‘‘just been shot” by the Coho. He hasn't been heard from since.