RedactedNarrative: Operator was operating a 36.5 ft. sailboat in Lake Pontchartrain. The vessel was under power and sail. Operator stepped away from the helm and walked to swim platform to urinate. He fell off the swim platform into the water. Operator was able to grab the swim ladder and was dragged by the vessel for an undetermined amount of time until it struck the Causeway Bridge. Operator was able to reboard the vessel at that time. STPSO deputies responded to the scene and escorted Operator and his vessel to Mandeville Harbor. During the interview of Operator, Agt. observed several indicators of intoxication. SFSTs were conducted and Operator was subsequently arrested for DWI and Reckless Operation. All PFD requirements were met and alcohol use is suspected to be a factor. Operator sustained minor abrasions to both hands and refused medical treatment from responding EMTs. The main sail and spreaders on the mast were damaged, along with support cables on the mast. Slight/Minimal damage to the bridge was observed .