Literally... a hat trick. The Top Hat Roll.
"This can be performed with any prop, but a top hat is traditional. The paddler must be able to roll one-handed. For a right-handed roll he removes the top hat from his head with his right hand and capsizes to the left. As the boat settles upside-down the still-dry hat is placed on the upturned hull with the right hand. It is retrieved with the left hand as the roll is completed with the right hand and placed, still dry, back on the head"