Slow going: A tug boat (above) nips into ice behind a lock gate to dislodge chunks at the Welland Canal. The frigid weather has been slowing down the ships recently, like lake freighter Canadian Prospector (right). Normally. the St. Lawrence Seaway is closed by now, but long shutdowns of the system earlier this season have forced the authorities to keep it open. Tug boats were brought into action to keep the system from clogging up and to let the last of the ships reach their winter berths or faraway shores.