Thankfully in the pre cellphone era, I was on a canoe trip in Algonquin Park. In the middle of a large Lake, the call of nature struck with a sense of urgency that required a solution quicker than just, "Paddle harder to land."

A jump into the lake and removing of trousers resulted in an "Aqua Dump". But alas it was a floater, rather than sinking to the unknown depths. It was a shocking discovery at the time.