Well, with Keel Hauling, you can 'forget' to keep the rope moving.
And these days one can kick up the ships speed fairly quickly.
So he can get battered against the hull the entire time.
And if he comes loose from the rope in front of the ships screws, oh well.
So it is better from one point of view -no chance of survival, but it is a more severe punishment due to certain death.
I'd imagine it was pretty hard to hold your breath while your hide was being scraped off against the barnacles on the ship's hull.