SAN FRANCISCO (CBS SF) – Australian Trent Grimsey plunged into the San Francisco Bay Friday morning in an attempt to shatter the decades-old record for swimming to and around Alcatraz Island after setting off from the San Francisco shoreline.

In 2012, Grimsey broke the speed record for swimming the English Channel.

In 1989, Tiburon native Bob Placak completed the roughly 2.7 mile round trip in an hour and five minutes, according to the publication Open Water Swimming.

Grimsey was attempting to better that mark after departing from the Aquatic Park Cove near Fisherman’s Wharf.