The Welland Canal is a ship canal in Canada that runs 42 km (27.0 miles) from Port Colborne, Ontario on Lake Erie to Port Weller, Ontario on Lake Ontario. As part of the St. Lawrence Seaway, the canal allows ships to traverse the Niagara Escarpment and avoid Niagara Falls. "Hogging is a term used when a vessel is bent up in the middle due to any number of factors. On the Great Lakes this happens to vessels in hot weather where the upper part is heated more than the submerged part. That's why you see boats with sprinkler systems spraying cool water over the decks to reduce this hogging. It's a safety check to prevent damage to the lock gates by making sure no part of the bow extends over the gates which could cause damage to the gates when the ship is lowered. In the down position, the sensor cable on the yellow gate is slightly below the top of the gates. If it touches anything in it's travel then some part of the bow is too far forward and the ship will have to reverse slightly.