Captain Bob, author of the posting below, used to be the MTOA Port Captain for Charleston. I don’t think anyone knows more about Charlestonian waters than Captain Bob.
This message was extracted from an ongoing discussion on the MTOA List-Serve, about whether it’s best to cruise south (or north) via the AICW, or go outside in the briney blue, or some combination of the two. Bob’s review of the Charleston inlet situation is one of the best I’ve seen on these waters, so I have take the liberty of reproducing it here.

Charleston is a real bear – at high tide the jetties are just below the surface.
John Is correct: The rock jetties are underwater at High Tide and has snagged a few Sailboats and Recently a MainShip Cruiser. These folks try cutting the channel or just are not paying attention.
With all the Commercial traffic Charleston Harbor has to be one of the best Marked Harbors Going. Especially at night the multitude of Range Lights are superb.
Daylight approaches keep a watch over your shoulder for a tanker or container ship for inbounds and keep an eye out for the outboard traffic At all times Stay in the Channel and pay attention.
The last guy on the jetties called Towboat U.S. for an escort in at night but got impatient and before Towboat U.S. got there the owner put his nice Mainship on the jetties.
Save Cruising and Ya’ll come to Charleston.
Capt Bob
M/Y ALLEZ! MT50 WB

I just thought I’d post my concurrence on how well marked Charleston is and also how accurate the charts are. I find it hard to believe that anyone who has taken the time to review a chart could end up on the jetties. We’ve entered Charleston twice and exited Charleston twice thus far. The first entry was in dense fog and the harbor was closed down to commercial shipping traffic. We couldn’t see any of the buoys and we were within 50 feet of them. If I could post pictures, I would. Our radar overlay on the charts of the area was so accurate I was actually able to perfect our calibration and alignment. The jetty returns and the buoy returns exactly lined up with the chart. I was amazed! We were able to get all the way to the anchorage off of the Megadock without any issue. The other entrance, and both exits, were done in the dark, and the number of lights and marks was excellent – not too many to make it impossible to figure out where you are, and enough that you could line up your course without having to worry. I can’t think of any other inlets we’ve entered or exited on the US East Coast that have been so well marked, and we’ve been through many since we mostly run on the outside.
Chris
S/V Pelican