Official reports say no alcohol. Although one news source mentioned cannabis found on the boat. Anchor, swim line, preservers, person staying with the boat ... any of these could have made the difference.
The guy they've recovered was an experienced sailor. I'd bet he'd never dream of taking off his harness runnin' the Mac. Seems like familiarity caused some overconfidence.
Survivor Of Boating Accident Says 'I Wasn't Ready To Die' - cbs2chicago.com