Tractor Beam
A weapon with this special property can generate a stable beam of gravitons, creating a tractor beam that can move other ships. In addition to dealing damage, a hit with a tractor beam prevents the target ship from moving normally. The gunner can push or pull the target ship (at a rate of 2 hexes per round, resolved at the beginning of the helm phase), or hold the target ship in place. The pilot of the targeted starship can attempt a Piloting check (DC = 15 + 1-1/2 × the tier of the firing ship) to break free of the tractor beam as her action in a round. When a tractor beam weapon is locked on to a starship, it can’t be used as a regular weapon. A tractor beam is effective only against ships of the same size as the firing ship or smaller; larger ships are unaffected by the tractor beam.
Source
Core Rulebook pg. 304