The main channel is around 40' deep, but narrow. 30' in some places which can make it tight for 2 boats. The north channel to some of the marinas is 8' at low tide, as is the south channel. There is some problems at low tide to get from the north to the south channel 3' and not more than 12' wide. Sterling Marina is the only full service marina with north channel access. You have several marina choices with the south channel but it's a little tricky getting to them. Our boat draw almost 4' and is 13' wide. I have brought it in the south channel several times, but, its been 4 years ago because she is now in Roatan< Honduras. Let me know if I can help you more.
Jim Fentress