keel over

verb3

1. •
   Of a vessel: to roll so far on its side that it cannot recover; to capsize or turn turtle.

   • What a tiny little schooner! But is it not bold to spread both sails? And see, now that we have come round to the wind, how the skiff keels over. — 1844
2. •
   To collapse in a faint; to black out, to swoon.

   • We should all go inside before somebody keels over from the heat.
3. •
   To die.