You'd be doing some swimming 45° into a current for the most part as well, thats a constant thing you'd have to fight, no chance to take a breath or you lose too much progress.
there are a few records where people swam ocean lengths not that far off in different conditions so it's entirely doable, however you could just walk into a cannon and get launched and completely negate it, you yourself being a projectile is legally not a vehicle, boat, an object that is purpose built to keep you afloat, etc, and you just walk throughout the entire duration of your trip
You'd be doing some swimming 45° into a current for the most part as well, thats a constant thing you'd have to fight, no chance to take a breath or you lose too much progress.