Sault St. Marie Lock
The trip up the St. Mary's River from the northwest of Lake Huron to the south tip of Lake Superior was quite an adventure.
The year I was doing the trip the current in the river was higher than usual - and hence running between three and four knots. The top speed of my boat under 'cruising' power was five knots and having to go over twenty miles it was two long days of motoring. Psychologically, it was very hard. Having the engine work so hard and to be making just over a knot it was remarkably frustrating.
I was tempted to give up a few times - but sailing in Lake Superior was a really big deal for me so I stuck it out knowing I would eventually get to the Sault. I hugged the shore keeping my eyes glued to the depth sounder to make use of any slower current or eddies of which I could make use.
Eventually I got to the Sault. The locks are easy to traverse - not many recreational craft go through these locks and the lock-master seemed a bit unsure what to do with me! There was no commercial traffic expected for a while so they just let me through. There was hardly any turbulence.