On a recent sail we where bringing Petite Helene (draft 6') back down the Clear Creek Channel. We hit something SOLIDLY IN the Channel just inside of #4. We were about a half a boat length inside of #4. I suspect it's the remnant of a previous #4. Please allow at least a boat length of clearance in the channel inside of #4. It could save a lot of damage. Fortunately, we were only going about 4 knots and Petite Helene is really well built. It paid off then with no damage according to the divers. I have tried to report it to the Coast Guard but so far I haven't been able to get ahold of them.