San Francisco Fire Department spokeswoman Mindy Talmadge confirmed to Press Association Sport that Andrew 'Bart' Simpson was taken to St Francis Yacht Club on the shore where paramedics performed emergency resuscitation, but he was pronounced dead.
She said another sailor suffered minor injuries.
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The decision was met with outrage and anger by UK cities which were on the shortlist for the prestigious award.
Mr Lewis is one of a number of Labour and Tory MPs under investigation by party officials over allegations of inappropriate conduct.
A jury has failed to reach a verdict in Emile Cilliers' trial on charges of attempting to murder his wife by tampering with her parachute.