First thing I've built with redstone. I rarely see a practical use for redstone in single player, but this is one. It will not impress anyone from a technical standpoint, but I thought it was a cool idea. Pressure plates work as the "dock," holding back water, and the boat presses the plates, lighting up torches on a tower.
Here's the basic one:
And here's the cooler one. I can "throw" a boat up a waterfall, and it will be moved over to the pressure plates automatically. This is the contraption at the top of the waterfall. You can see the hole where the boat comes up the elevator in the bottom left:
And here is the view from below, where I would throw the boat up the elevator, and the torches lit up at the top.
The main problem is animal interference, but I could probably fix that with cactus...
If anyone honestly wants a tutorial, just look up any "redstone basics" tut on Youtube. It is probably the most basic thing you can do with redstone torches. It's just one path of redstone, with one torch in the middle.
Push it. It doesn't hang up on the pressure plates because it's already sitting on some.
Same concept as building docks out of half-stones. They hold back the water, but the boat sits higher than them. You can steer onto a suitably large half-stone dock at full speed with no worries of crashing the boat. And you can push a boat off the dock back into the water.