Two Days on the S. Car. Inter Coastal Waterway

Having sailed out in the ocean from Fort Lauderdale to St. Augustine and from there to Savannah, our next two hops, from Savannah to Beaufort SC and from there to Charleston SC were in the Inter Coastal Waterway ICW) called "the ditch". Our distances were 43 and 59 nautical miles on the two days.  Here, waves are not a big concern and winds are normally light but the path is twisty, so this is mostly a motor propelled journey. however, we did set the little jib for a bit more propulsion and even sailed the last ten miles to Beaufort SC on a favorable current up the Beaufort River. Sailing in the ocean, auto pilot steers us to our destination for hours, with occasional checking and minor adjustments of one degree to port or to starboard if ILENE drifts off a bit. Here, however, there are buoys or day markers (buoy signs on stakes) every few hundred yards requiring the helmsperson to pay attention to the charts, the GPS and what his or her eyes are saying, to keep on a course with numerous bends of up to 90 degrees.

There are a variety of conditions as to depth and width in the ICW. While average depth in this stretch was an estimated 15 feet, we experienced 30 feet or more in some places, and the scary sound of our depth alarm screaming at us that we had less than seven feet (16 inches under our keel) in some stretches and once less than six feet. Some of the Sounds we traversed were a mile wide with sufficient depth through most of their width. Others are just as wide but have a deep enough channel cut through them that is quite narrow. Here we are following another boat and it looks like there’s nothing but room. But if you notice the red triangle on the post, you can see that we have to pick our way from pillar to post to stay in the deep channel.

A shrimp boat overtaking us:

Our vigilant lookouts enjoying a calm passage:

We passed big homes with long piers leading out to their pavilions and floating docks.

 

We meant to take a photo while passing Hilton Head of the beautiful circular marina with the red and white lighthouse that my brother likes to visit, by land, but while passing we were overtaken by a strong rainstorm that obliterated visibility. But we did photograph a less picturesque Hilton Head Marina.

Daily distance to be made is relatively easy to compute because the charts have magenta lines, perpendicular to the twisting track of the ICW, at intervals of every five statutory miles. So with Beaufort at statutory mile 536 (one away from 535 by extrapolation) and Charleston at 467, the difference is 69 statutory miles. But our speed is in knots, meaning nautical miles per hour, and a statutory (land) mile of 5280 feet is .88 of a nautical mile of 6000 feet. I round this 88 percent to 90 percent so I just subtract ten percent, reducing the 69 statutory miles, by let’s say 7, to 62 nautical miles. This means that with let’s say 14 hours of daylight, if we leave at 6:30 am, we will get to our destination by 8:30 pm nightfall even if we only maintain an average speed of only 4.5 knots. The first day was easy and, as mentioned, we actually sailed a bit and got in at about 4 pm. The second day was longer.

Speed is very dependent on tides, bridges, depth and unexpected circumstances.  In shallow water we go slow. As to tides, the ICW in South Carolina uses rivers and sounds that run from the land to the sea, with canals cut through between them from one to another in strategic places to shorten the course.  If you get a favorable tide ebbing out to sea on one river that you are following toward the sea, that tidal flow will be continuing in the same direction for six hours in the next river, where you may be motoring upstream against the tide and current. And only persons with excellent knowledge of the local waters will know which way the tide will be flowing in the man-made canals between the rivers. We sought to motor at six knots, and actually made as much as 7.8 knots over the ground with the tide and as little as 4.2 when against it.

Most bridges we encountered were the modern ones, with the bottom of the span in the center being 65 feet above the water level at the normal high tide, sufficient for us to pass under at any time because the top of our mast is only 63.5 feet above the waterline. Such high bridges are expensive to build, but low expense because bridge tenders need not be hired. They have signs with numbers posted at the footings of the bridges which show the exact number of feet from the level of the water showing against the sign at the time of your passage, let’s say 68 feet at low tide and as little as 62 feet at extreme highs caused by full or new moons and flooding.

But there are also lower bridges that have to be opened by their tenders.  Some open on demand and others, only at fixed times. We had a problem with one of these, located only a few miles before Charleston, caused when our engine stopped for a few minutes.  We burned a lot more fuel per hour than I had realized while going full tilt, as we had coming to Savannah, than at idle speed with no load as when chilling the refrigerator. Our aft fuel tank had run dry.  It took me a few minutes before we could get it started again using the other, forward fuel tank, which was full.  On the day of that stoppage we had followed a boat called “Autumn Borne”, with a hailing port of Buffalo, NY, through the bridge at Beaufort, SC, at its 7:30 am opening.  I had asked Lene to call them to strike up a short conversation about where that they were going. They said that they were headed for Charleston, as we were that day, had done this trip many times, and offered to let us follow them, which we gratefully accepted.  In fact, the first photo in this posting shows them ahead of us. We had the small head sail up, more for stability than speed, when the engine stopped. We still had one knot of propulsion and we called them to tell them that we would be dropping back and would catch up with them at Charleston. But they, as I would have done, returned to provide help if needed, though they did not even know our names yet. It is a beautiful thing that sailors look out for each other. 

A few minutes after our engine came back to life, they told us that the low bridge near Charleston had no openings from 4 pm to 6:30 pm - rush hour for the land people.  I confirmed this, and doing the math, later reported that if we could maintain six knots, for the remaining three hours until 4 pm, we would be OK.  Autumn Borne concurred. We were actually going faster than six knots until we came to the cut over which the problem bridge crossed. Then we hit the strongest adverse tide of all. Even running the engine at full speed, we were slowed to 4.2 knots for about a mile. When the bridge came into view, we saw that it was already open to permit a big dredging rig to pass. We hurried and made it under that bridge with 13 minutes to spare. Whew!

We will soon report on Beaufort and on Charleston, but the next leg on the ICW has a notoriously shallow stretch and so we hope for weather that will permit us to sail in the ocean.

Posted from Charleston, SC.