RedactedNarrative: On July 22nd, 2021, at approximately 1200, Lieutenant was contacted by S.O. in reference to a single vessel fatality boat incident that occurred on Grand Bayou in Lafourche parish. Operator had just launched at Grand Bayou launch heading west. Shortly after crossing under Hwy 20 bridge and while following a friend’s vessel, he attempted to get on step. Witness told Agents when he got to the corner, approximately 200yrds from bridge, he looked back and did not see Operator. Witness told agents he turned around and went back. Witness told agents he found Operator's vessel sinking. Upon reaching his vessel, Witness said he observed Operator approximately 10’ from the sinking vessel. Witness told agents that Operator was bobbing and spinning, with his head occasionally being fully submerged under the surface of the water. Witness said Operator was unresponsive so he grabbed him and managed to navigate to the Northern bank while holding onto him. Witness contacted his wife, who then called 911. Witness attempted CPR on Operator. Once Witness's wife arrived on scene, the couple was able to drag Operator onto the bank and continue CPR. S.O. arrived on scene shortly after and took over administering CPR. Operator was never able to be resuscitated and was declared deceased by the Lafourche parish corner. Alcohol and or drugs are not contributing factors. Agents were able to recover his vessel. Agents observed his vessel to be an open, homemade, remote steer and approximately 15’ in length powered by a mercury 50hp. Agents observed the throttle advanced to full with the key switch in on position. Agents observed three of the driver seat mounts pulled out of the vessel floor and the seat leaning towards the starboard side. Operator was not wearing a PFD (a new PFD was found on back seat of his SUV). Operator did not utilize engine cutoff switch. Agents learned that Operator had very little vessel experience which is a contributing factor.