If a mage with the ability to generate heat, used this to heat the water around an ocean vessel, would they be able to do it in such a way that propels the ship? I was thinking something similar to the gulf stream.
- A Mage able to Generate large amounts of heat nearby, up to a hundred feet or so beneath the ship
- Said mage can also manipulate heat, move it, and make an area colder
- The ship in question is of any "medieval" size, within the range of a small rowboat to a large Cog etc.
I'm also specifically asking about in an ocean setting, but input on using this on rivers, or other bodies of water would be appreciated.