In June 1972, Poenisch tried to establish a long-distance ocean swimming record off of Florida but was pulled from the water after sharks attacked his safety cage.
In 1976, he swam 125 miles in the Florida Straits and was listed in the Guinness Book of World Records for the longest ocean swim.
To memorialize his 65th birthday in 1978, Poenisch set out to be the first to swim from Havana, Cuba to the Florida Keys.
[1] Poenisch died in June 2000 and, as of September 2013[update] had not received official recognition for his 1978 Cuba-to-Florida swim.
In August 2017, Poenisch was inducted into the International Swimming Hall of Fame as a "Pioneer Open Water Swimmer.