keel over   
phrasal verb with keel verb uk/kiːl/ us/kiːl/
  (PERSON)      
  突然倒下
to fall over suddenly
  He finished the bottle, stood up to leave, and keeled over. 他喝完了那瓶酒,起身离开时突然跌倒在地。 
   (BOAT)      
 (船)倾覆
If a boat keels over, it turns upside down in the water.
  The storm raged and they struggled to stop the boat from keeling over. 风暴肆虐,他们努力使船免于倾覆。