[keel over] {v.}
1. To turn upside down; tip over; overturn. — Usually refers to a boat.
* /The strong wind made the sailboat keel over and the passengers fell into the water./
2. {informal} To fall over in a faint; taint.
* /It was so hot during the assembly program that two girls who were standing on the stage keeled over./* /When the principal told the girl her father died, she keeled right over./