Due to persistent shoaling, in early 2011 we designated the Waterway south of McClellanville to Awendaw Creek, as an “ACW Problem Stretch.” As before, we recommend passage at mid or high tide.
And what began as a caution has turned into an excellent discussion on GPS. Read and learn!

Yesterday we traveled from Charleston to Georgetown on the ICW. At GREEN 43 we were dead on the magenta line when the depth under our props went to 0.2 feet. We draft only 39 inches so this is really a problem for most boats.
We put out a securite call on the VHF and saved a couple of boats from going aground. I later heard chatter from a couple of sailboats we had passed earlier that they were having to wait for high tide to traverse this section. It was only a bar and lasted a few seconds as we cleared it but it gave us a start. Today I heard locals in Georgetown talking about trouble in the same place. Be careful out there.
Rusty and Jan Carlisle

I too experienced the shallow water following the magenta line on my Garmin 4210 in this area. I have found that Mr Garmin has put my “boat cursor” in the marsh while in the waters of Georgia and S. Carolina. I have find deeper water by going off the magenta at slow speed usually toward the inside of turns. I poke around a bit and find the “real channel”. With all this said, I still love my Garmin electronics. Most of the time the magenta is right on.
Rick, Sun Gypsy

I think you meant the outside of the turns. General rule of thumb is stay 2/3 rds of width to the outside. Imagine the current flow scouring out a channel. The scouring velocity is greatest on the outside of the turn.Seek the side with larger vegetation and steeper banks. Of course there are many other factors that can cause variations with this “thumb” rule.
Joe

This may or may not be another example of what can happen by spending too much time following the magenta line rather than using visual observations and following the channel markers instead. Often coming up and down the waterway, we found our plotter showing us crossing land instead of being in the channel. We have transited this section many time and were told by other boats over the VHF that there was shallow water, one telling us they
found 4 feet in the channel. When we crossed we actually found 8 feet of water in the channel some five minutes after they passed through. There are other areas like Cumberland Dividings where following the chartplotter will put you solidly aground. I’m not saying this is the case here, but would caution everyone to not depend on the plotter for more than a reference and use good old fashion navigation. When I hear any reports that the boat was aground and on the magenta line, I have to ask myself how accurate the plotter is in this section. Many boats will make the same mistake and before long there are several reports of groundings because too many of us religiously follow the magenta line. The towing companies will often tell us that they have pulled many boats off shallows in the area. The reason is because following the plotter into shallow water is a common problem. We often see many boats running from green to the next red marker down a channel instead of staying well in between the markers. Many channel markers along the ICW sit in one or two feet of water, but boaters will think that as long as they are inside the markers the channel is deep. Running up close to them will almost always lead to a grounding. Since our first trip south on the ICW in 1993 we have observed so many boats hard aground in what they thought was the channel, while we passed safely by. The depths do change for a variety of reasons and caution is always needed, especially in known problem spots. We too follow the various websites looking for the latest information, but often find reports that are based on operator inattention more than poor conditions. Some channels are less forgiving than others should one stray too far.
Chuck Baier

The problem isn’t with the chart plotter, it’s the map they used. The GPS is telling you exactly where you are, but the channel has moved relative to the chart that is published that was used on the chart plotter. The magenta line is published on the chart, and so if the channel has been moved by the moving water, which it has, then the magenta line will lead you astray.
Follow the channel, NOT THE MAGENTA LINE! Makes no difference how new your chart plotter is, it has to do with when the chart used was updated. When you update your chart plotter, hopefully they have used the latest charts available.
Chuck Gorgen aboard ODYSSEE

Click Here To View the Cruisers’ Net’s “AICW Problem Stretches” Listing For the Waterway south of McClellanville to Awendaw Creek

Click Here To Open A Chart View Window, Zoomed To This AICW Problem Stretch

Due to persistent shoaling, in early 2011 we designated the Waterway south of McClellanville to Awendaw Creek, as an “ACW Problem Stretch.” Capt. Long gives us even more specifics. As before, we recommend passage at mid or high tide.

Here is my track through the shoaling a mile south of McClellanville, mile 431. I went through at low water and could visually see the shallow spots that account for the “S” curve. I dug what felt like about a 3″ inch trench at the spot indicated at N33 04.239 W79 28.412. I don’t think there is a straight path through here at low water for a boat drawing more than four feet.

Click Here To View the Cruisers’ Net’s “AICW Problem Stretches” Listing For South of McClellanville

Click Here To Open A Chart View Window, Zoomed To This AICW Problem Stretch

As you approach the southside of McClellanville on the AICW, please heed earlier advice to favor the red side, especially in the stretch between markers 37 and 38. Please open the links below for more information and a Chart View of this area.

Passed through this area 10/30/2011 without any indication of shallow areas. Carried over 12 foot depths and mostly deeper. Strong currents and erratic currents were common.
Harry Miller

Came through this stretch at absolute full-moon dead low tide 10/25/11. Took a lot of patience and feeling our way, the good news is we never saw less than 7.0 feet.
Dan/Jaye Lunsford

Of note are the shallow readings showing on our depth sounder from McClellanville almost to the Isle of Palms. When we came out of McClellanville, we saw readings as low at 5.5 feet but mostly 6 or 7 feet (as O.G’s depth transducer is 2 feet below the waterline, these reading translate into 7.5 feet to 9 feet, well below the nominal 12 feet supposed to be throughout the ICW. This is of no concern with our 4.5 foot draft, but I thought it worthy of note for Claiborne Young’s “Salty Southeast” blog.
Captain Ted Jones

We passed McClellanville, SC at low tide this morning, 3/14/2011. As anticipated, we hit very shallow water between markers 37 and 38. At one point, about midway through this section, we saw 3’9″ and were plowing through the mud. We were favoring the red side somewhat.
Skipper Larry Thackston on M/V PEACH

Went through today (5/8/11) , 1 hour before high tide and saw no less than 9.5 feet at my transducer which occurred at Marker 40 and 35 A. The transducer is two feet below the surface so looking at 11.5 feet. With an 7 to 8 foot fall it might be a little skinny for some boats.
Capt. David

5/16/2011
With an almost full moon low tide we passed through the AICW Channel South of McClellanville, SC. Unfortunately, a late start from Charleston had us arriving at Green 47 at low tide, but we made it through with our 6′ draft without a problem.
The least water we saw was 6.1′ when we turned into the wind near G47 to take down the mainsail. We were on the green side, but well inside the channel. Recommend staying on the red side at R46.
The rest of the way up to R32 was in 8-9′ range with a couple of spots that flashed at 6.9′.
As recommended we found the best depths by staying centered in the channel.
Also note that Green 27 is missing the northbound face place.
And an oh by the way, just north of McClellanville, we spotted two alligators casually swimming in the channel. One in the 7-8′ size range and the other 5-6′. Think twice about that little swim along this leg .
Capt Pete

Click Here To View the Cruisers’ Net’s “AICW Problem Stretches” Listing For South of McClellanville, SC

Passed through this area 10/30/2011 without any indication of shallow areas. Carried over 12 foot depths and mostly deeper. Strong currents and erratic currents were common.
Harry Miller

Click Here To Open A Chart View Window, Zoomed To the Location of South of McClellanville

Click Here To View An Earlier Posting on this Area

Please note that this grounding was near high tide in the center of the channel. We have reports of recent shoaling in various spots in the AICW between Charleston Harbor and McClellanville, particularly at Mile 431. Past advice has to been to stay in the center of the channel. Maybe this new spot will be an exception. See the link for more on this area.

We hit a shallow spot (less than 5 ft) north of Charleston just past Graham Creek between markers G64 and G61. It was close to high tide and we were aground right in the middle of the channel just opposite a small creek on the east side. I suggest staying to the green side of the channel to avoid this spot!
Captains Harriet and Skip aboard S/V Moondance

Click Here To Open A Chart View Window, Zoomed To the Location of Shoaling Report

Click Here To View An Earlier Posting on Depths South of McClellanville

As you approach the southside of McClellanville on the AICW, please heed earlier advice to favor the red side, especially in the stretch between markers 37 and 38. Please open the links below for more information and a Chart View of this area.

After anchoring in the South Santee River we headed for Isle of Palms yesterday morning ( 11/5/2010 )… we traversed the McClellanville stretch 2 hours after high tide (falling) all seemed well in the middle of the channel until we sited depths in the 5 foot range in 3 different places through that run … all in mid-channel … had our water tanks been full, we’d have grounded for sure.

Transited the area today about 2 hours before low tide. While we did see the occasional 8′ or 7.9 we saw nothing approaching 5′ while following the channel. The channel does indeed favor the red in general (that is, it is NOT in the center of the water) but it was quite possible to transit in relatively low water.
Captain Leigh

Click Here To Open A Chart View Window, Zoomed To the “Alert” Section of the AICW South of McClellanville, SC Where The Shallow Water Described Above Was Encountered

Click Here To View An Earlier Posting on this Area

Captain Pascal pilots a vessel with a 6.25 ft draft and, naturally, keeps a sharp eye on his depth finder.

MM430, near McClellanville,
[Found] 9′MLW between G35 and G37, 8′ to 9′ MLW between G37 and R40
Pascal

As you approach the southside of McClellanville on the AICW, please heed the advice given below, especially in the stretch between markers 37 and 38. Please open the links below for more information and a Chart View of this area.

Submitted on 2010/06/14 at 12:16pm
Hit the McClellanville area in early afternoon Saturday, June 12 near low tide. A 44 ft power boat was aground on the green side between markers 37 and 38. Hang near the red side as I had no problem there.
Capt Jim J.

Click Here To Open A Chart View Window, Zoomed To the “Alert” Section of the AICW South of McClellanville, SC Where The Shallow Water Described Above Was Encountered

This new information is contrary to the several recent reports we’ve received of shallow water in this area south of McClellanville and, as such, is very welcome. Check out the link below for other cruisers’ comments and a Chart View of what has been for some a troublesome stretch of water.

We passed through McClellanville, SC this afternoon a little more than an hour before low tide. According to the info on my chart plotter we were about 1 foot over low tide at the time. We stayed on the magenta line most of the way and the lowest reading we observed was 8.8 feet in the vicinity of marker 38. I know my depth sounder is accurate so if you believe the tide info from my plotter and our readings the lowest you should encounter in that stretch is 7.8 feet. This is about what we observed in the fall.
Captains Ray and Helen
aboard S/V Rigamarole

And, as of 5/26/10, we received the reports below from the Army Corps of Engineers Office in Charleston, SC. Looks like the waters in question south of McClellanville were just dredged in March and April of this year. Hopefully, these projects have deepened depths along this stretch of the AICW for some time to come!

FINISHED DREDGING BETWEEN FR-38 AND R 42 THE MIDDLE OF APRIL.
Captain Mike

ALSO DREDGED FROM FG-35 TO MATHEWS CREEK IN MARCH.
Captain Mike

More info as of 5/25/10 that dredging seems to have improved depths along the Waterway south of McClellanville!

We passed through McClellanville, SC this afternoon (5/25/10) a little more than an hour before low tide. According to the info on my chart plotter we were about 1 foot over low tide at the time. We stayed on the magenta line most of the way and the lowest reading we observed was 8.8 feet in the vicinity of marker 38. I know my depth sounder is accurate so if you believe the tide info from my plotter and our readings the lowest you should encounter in that stretch is 7.8 feet. This is about what we observed in the fall.
Captains Ray and Helen
aboard S/V Rigamarole

Click Here To View An Earlier Posting Which Found Very Different Depths on this Portion of the Waterway

Click Here To Open A Chart View Window, Zoomed To the Stretch of the AICW South of McClellanville Where Shallow Depths Were Reported Earlier

Captain Jenkin’s and Captain Thomason’s reports below on less than ideal AICW depths south of McClellanville are not the first, and almost assuredly won’t be the last here on the Cruisers’ Net about this section of the Waterway. There is good reason to belive this stretch will be dredged in 2010. Let’s all hope so!

Subject: Shallow water south of McClellanville
Cruising News: We found the shallowest water to be 7′ at mid tide south of SM 430 to R 42.
Dave on GB 46 At Last

By the way, the depths south of McClellanville continue to be a problem. We purposely went through at high tide but there would be 7 ft at low tide in some places. Farther south, north of Cjarleston there were spots even more shallow than that.
Jean Thomason