[luvbach1]

You're correct that tipping a boat is one meaning for careened, but the dictionary states that careening also means "To lurch or swerve while in motion," without mentioning a boat, so it could also apply to a car. So apparently both careering and careening are correct.

[hellbender]

Careen is nautical term for heeling a boat over, and that is the only definition in my Oxford English Dictionary. When a word is misused for years, lesser dictionaries will cave in and start listing the misuse as a secondary meaning. The fact is that careen got this misuse because it sounds like "career."

Something similar is happening today with the word "eke," which means to supplement. Because it reminds people of "squeak," it is frequently being used to mean "barely get by," as in "Bush eked out a victory over Gore."