2018 ICW Southern GA, STM 684 to STM 640
Note: We use Navionics Sonar Charts in parallel with our chart plotter for navigating the ICW. They are another tool to have at your navigation station, they are pretty accurate, and much more detailed and accurate bathymetry than NOAA or Garmin charts, but they are not perfect and must be used with caution. If you use these charts you MUST update them every few days for the area you are transiting. Navionics releases new information all the time and an old Navionics Sonar Chart is an old chart. Set your depth shading at 6 feet to match the NOAA 6-foot contour. It makes it easier to transition back and forth between different cartography of NOAA and Navionics.
Southern GA, STM 684 to STM 640
9.Jekyll Creek STM 681.5 This has been a shoal area for several years. But there is 9 feet of tide here so with a little planning it is easy to transit. Our observations, after a number of transits over the past few years, is that if a tug and barge go through at near low tide, the channel is a bit deeper for a few weeks or a month. This was the case in the spring of 2016, but it filled in again. In November of 2017, the best water we could find was about 3.5 feet. A barge went through in mid-February 2018 and our passage on March 19, 2018, showed depths of about 5 feet in the worst section near G19. The same area where in November we only found 3.5 feet. We were running Navionics Sonar Charts on an iPad at the helm and we “drove the white”, meaning we tried to steer to and through the charted 6’ depths. We followed what Navionics suggested was the deepest water and what we saw would correct to 5 feet MLLW. If the tide level is not right for your passage, check into Jekyll Harbor Marina. Use the golf cart to explore the island, and visit the Georgia Sea Turtle Center.
10. Buttermilk Sound R208 STM 659 There is a distinct shoal building into the ICW. It is located about 400 feet SE of R208. At 31 8.744 N and 081 20.984W. It shows clearly on the Navionics Sonar Charts. If you are using NOAA charts or other cartography, you might just put a warning waypoint on your charts. Being that it is on the red side of the channel this is more of a concern headed south when you naturally stay closer to the red side of the ICW.
11. Little Mud River STM 655 Little Mud river has some shallow spots in the ICW channel. Our track was established by the suggested deepest water shown on the recently updated Navionics Sonar Charts. We steered the boat according to the deepest water seen on the Navionics chart. Our course slalomed back and forth as we followed the suggested deeper water. In the end, we found nothing less than 5’3” along our track. A track right down the center or 30 feet either side of our track might have seen different and shallower water depth. My best guess is that a track straight down the middle would see shallower depths there are probably some places with less than 5 feet MLLW between R194 and R192.