[lexicality]

canals have negligible water flow (except during disasters!) so I don't think that'd work very well. They also get dredged occasionally so there's a decent chance anything you leave down there won't last more than a couple of years

[DonHopkins]

> They also get dredged occasionally

And it's fascinating to watch!

https://www.youtube.com/watch?v=aGFC6MF5-_k

[fragmede]

They do have tides though, so make it a big fan that points up.

[wbl]

Depends on the canal. The UK narrow boat network has locked everywhere so minimal current in most sections similarly the Netherlands. In fact most canals. But then you have something like Suez which is just open to the ocean.

[fragmede]

The UK locks themselves are water movement though, so if you wanted to power something for "free" on those, you'd attach it to there. Oh man did I love watching those as a kid. You wouldn't do a fan though, you'd have a line and a buoy and use the up and down motion to drive a linear electromagnetic generator to harvest energy.

[fennecbutt]

Yeah but it's not really a lateral flow of water when the locks fill up and empty.

[lexicality]

you do get lateral flow up/downstream during filling and emptying, but it's generally considered rude to do it fast enough to cause turbulence