I was returning from Ossabaw sound in Savannah Saturday in my 22ft trophy. As I was coming up the inter coastal to my marina, there was this little 16ft trihull driving like a typical nut. Speeding through no wake zones, cutting across the bows of larger boats with only 10 to 20 feet to spare; and pretty much acting like a total jerk. Well, I noticed that he obviously didn't understand the channel marker system and did I mention this was at an extremely low tide? Well, he was about 5 ft from shore, in water where you could see the mud banks running wide open coming up on a small beach area. About the time I turned to my wife and said let's watch, he plowed right into a mudlat about 6 inches under water.. His moter flipped up and mud went flying about 15 feet in the air. My comment was 'one less jerk on the water'. I figure he must have messed up his lower end unit, his water intake and pump, and hopefully his motor as well.