RedactedNarrative: Operator and two passengers had just entered the Tickfaw River from Lake Maurepas when they struck a log that was floating just under water. The vessel then began taking on water in the engine compartment. The vessel was taken to a nearby dock and tied up. The vessel filled with water up to the bottom of the steering wheel. No alcohol or drugs are suspected. No PFD were worn or used. The vessel is a 1999 30 ft, Spectre Catamaran. The vessel has two 500HP inboard engines. Accident occurred due to floating debris. Sr. Agt. observed the floating log after the accident.