Welland Canal Port Maitland. With the opening of the extension, the canal stretched between the two lakes, with 40 wooden locks. The minimum lock size was , with a minimum canal depth of . Deterioration of the wood used in the 40 locks and the increasing size of ships led to demand for the Second Welland Canal, which used cut stone locks, within just a few years. In 1839 the government of Upper Canada approved the purchase of shares in the private canal company in response to the company's continuing financial problems in the face of the continental financial panic of 1837.
Welland Canal, bridge 13 By-Pass. Construction proceeded through the 1972 shipping season, and by the end of that season, work was close to completion. In the late evening hours of December 15, 1972, the Main Street Bridge raised to allow the passage of the Georgian Bay - officially the last ship through the city of Welland. In fact, the bridge was raised again the next day to allow a St. Lawrence Seaway service vessel to pass, but the Georgian Bay remains the official last passage under the bridge in most historical records. Following the closure of the canal at the end of the 1972