On the road back from Niagara falls on the QEW, you drive over a large bridge which goes over the Welland Canal. The Welland Canal connects Lake Erie in the south to Lake Ontario in the north, and is a vital link in enabling shipping traffic to pass from the Great Lakes system all the way up the St Lawrence River and into the North Atlantic Ocean. The interesting thing about the Welland Canal is that it is completely man-made. Of course, there is also a natural waterway that connects Lake Erie to Lake Ontario... it's called the Niagara River, but it has a slight obstacle to shipping traffic called Niagara Falls. The ships are able to go downstream ok, but they seem to have a hell of a time going back upstream.

Hence we have the Welland Canal - a massive 50+km manmade river which allows huge cargo ships to safely travel between Erie and Ontario. It is basically a detour around Niagara Falls. But the Falls exist because Lake Ontario is considerably lower that Lake Erie, and a large natural plateau exists between the two lakes called the Niagara Escarpment. This is essentially the cliffs that the Niagara river goes over to create the falls. So to compensate for the huge difference in altitude as you travel the 50+km canal, it passes through a series of "locks".

As we drove over the Skyway bridge, Gary looked down and noticed a ship travelling up the canal. We all thought it would be rather cool to see a big ship try to get through one of the locks, so we turned off the QEW, and managed to find the road beside the canal on the offchance that we might see some lock action. As we drove alongside the canal we finally found the ship steaming alongside of us, so we continued to the next lock which was a couple of kilometres upstream. With amazingly good timing, we managed to find Lock Number 3 and made our way to the viewing platform as the big ship approached.

The locks work by having an enormous channel - large enough to hold a cargo ship - with huge steel gates at either end. The water is lower at one end than the other, so when a boat wants to go upstream they close to top gate and open the lower one, letting the water in the lock go down to the lower level. The ship sails into the lock, they shut the lower gate, flood the lock so the water rises to the higher level and then simply open the top gate to let the ship continue on its merry way. Heading downstream is the same thing only reversed. Simple really.

There's a little more to it than that, but it's mostly just safety precautions - like tying the ship into position while the lock is flooded to ensure it doesn't move, and a few other precautionary safety steps - but basically it works as described above. We were lucky to be in the right place at the right time to see the Diamond Star - a cargo ship from Halifax, Nova Scotia - pass south through the lock heading for Lake Erie.

The whole process took about 45 minutes, and there are 8 locks to pass through on the Welland Canal alone, so you don't want to be in a hurry to get from place to place. Regardless, it is a remarkable feat of engineering and was very interesting to watch in action.