How do I sail rafts in Breath of the Wild?

Turns out you have to use some non-Newtonian physics to move rafts: while standing on the raft, wave a Korok leaf at the sail or push an object held with magnesis against the mast. I could not get the magnesis technique to work with a sword, so either it's been patched out or only certain (heavier?) objects work.

Get a Korok leaf and stand on the raft. Use the leaf to blow gusts of wind at the sail. Doesn't make a whole lot of sense and works a little janky but that's how I got around on them. I think this is the only way to get to a certain island as well.