So in essence they act like a little like nerves in the nervous system. But instead of transmitting electrical impulses, they conduct magical energy between foci, right? [Or maybe blood vessels in the circulatory system is a better analogy.]

Huh... [Uhhhh... if you say so. Still trying to figure how that would actually look and work.

Still drawing a blank. Any mental image that comes looks rather silly.] The only concern I'd have with that is what if the magic was suddenly cut off mid flight. I'd think the boat would need something that didn't rely on magic to be able to keep it up in that case, or at least slow its descent down.