A commercial fishing trawl has a net and a mouth opening defined by a head line, a foot line, and side lines. The mouth opening is spread by a plurality of foil segments threaded on one or more of the head line, foot line, or side lines. Foil segments may also be threaded on tag lines or foil lines attached about the mouth opening to spread and maintain the mouth opening as the trawl is towed through the water, behind a tow vessel.