RedactedNarrative: On 7-13-14 at about 3:30 p.m. Operator was operating vessel LA836EH on the Vermilion River in Lafayette Parish. The vessel was heading towards the Beaver Park boat launch. The vessel struck an underwater object resulting in the 200 Mercury outboard detaching from the transom of the Bullet bass boat. I pulled the vessel into the boat launch area to try and assist him in getting the vessel back onto the trailer before it completely became submerged. Operator was then able to free the motor from the vessel by cutting the cables and fuel lines. Upon observing the transom of the vessel once on the trailer, most of the transom was detached from the stern. Operator admitted that he had a loose bolt or two on the motor mount and it seemed like it may have been a little rotten before going out. No alcohol was found onboard the vessel. Operator also did not show any signs of impairment. Operator was utilizing a PFD and the vessels safety lanyard kill switch at the time of the incident. No injuries were found due to this incident at the time.