Originally posted by sarteck:

There's been some videos to show that... it depends. Usually not, but sometimes yes.
See FireSpark's video on it: https://www.youtube.com/watch?v=JSR-dOsaCdw

That video really is missing relevant tests. No test of tacking versus paddling with the longship, not changing sails when tacking so the ship loses speed. I'm not sure that I can draw any conclusions from it. His updated video still misses these points.