"Seamanship "Navigating the ICW" "
By Jeremy Hood
From the October 1995 issue of TellTales Magazine
Just recently, I came back from helping an owner take his boat to Florida. We had intended to do the whole passage offshore but easterly winds, an active hurricane season, and days lost to predeparture repairs led us to make the decision to get some easterly miles under our keel by taking the ICW, at least as far as New Orleans. Perhaps it is surprising that an ICW passage should test the skills of a navigator more than an offshore passage, but this really is the case; for in the ICW you need to be carefully following the charts, recognizing and following the buoyage systems, following the navigation rules in regard to other traffic, and using the VHF radio extensively. This month's column covers the first two of these, charts and buoyage. Following the Charts During the day an ICW passage is pretty straightforward, as you can usually see the next mark and head for it; though even this can lead to you go aground on occasions. When the ICW channel splits, where it crosses bays or open water, or where you cross rivers, it is essential to be aware of these things and to anticipate the potential problems. Just because you can see a mark does not automatically mean you should head for it. Unless you have been following the chart, you will not be able to tell from a distance whether the mark you are looking at is the next one along your course or whether it is marking another, separate channel. On more than one occasion have I had novice crew members head for a wrong mark just because it seemed right to them! When you are crossing a bay at night or in poor visibility, you may need to use the chart to calculate a course to steer between marks. From one mark to the next is sometimes quite a distance, and it is not uncommon that you have to leave one mark behind before the next one comes into view. Having a compass course to steer as you pass one mark is extremely helpful and makes such a bay crossing a lot easier. When passing through or across areas where currents are strong it is sometimes not sufficient just to head for the next mark, as before you reach it, you could be swept out of the channel and find yourself aground on the down-current side. Use the chart to anticipate areas of potentially strong currents such as bays, rivers and spillways, and then watch carefully as you cross these areas, staying on the up-current side if it is practical. The ICW Buoyage System Though for the most part the ICW buoyage system is straightforward, there are areas where it can be confusing, particularly where the ICW follows another channel for awhile. The ICW has a buoyage direction that travels south down the East Coast, then west around the Gulf Coast; thus, generally following a clockwise path around the U.S. coast. If you are following this buoyage direction, you should leave the triangular red ICW marks your right-hand side. You call remember the buoyage direction in several ways: Red, right, returning to Brownsville (the end of the ICW at the Mexico border). The red marks are always on the landward side, green on the seaward side. The direction of buoyage is clockwise around the U.S. coast. Special ICW Markings Nearly all ICW buoys are marked with a small yellow triangle or square, which indicates the mark refers to the ICW channel. Along most stretches of the ICW, the shape of the yellow mark corresponds to the shape of the buoy; thus, red triangular marks will usually have on them a yellow triangle. But this is not so where the ICW follows another channel. If you take the ICW eastward from Galveston Bay, you eventually reach the Sabine River. Here the ICW travels northward along the river for several miles before again turning eastward into a dredged channel. For the section where the ICW follows the Sabine River, you are really following two channels: the river and the Intracoastal. The river channel is buoyed from the Gulf northward so that red triangular marks should be left to starboard (red, right, returning). But if you are following the ICW eastward, you should leave the ICW triangular marks to port, because you are traveling opposite the direction of the buoyage. Where two such channels coexist, you need to pay particular attention to the SHAPE of the YELLOW ICW markings on the buoys. Along this section of the Waterway, as along other similar parts, the shape and color of the buoys or marks reflect the main river channel, and the shape of the yellow mark shows the ICW buoyage. Only by looking at the shape of the small yellow mark can you tell which side to stay to remain in the ICW. Along some sections (such as the Sabine River), the yellow marks are contrary to the main shapes; but this is not always so, and in these situations, careful attention to the chart, cruising guide and the marks themselves is important. Split Channel Lights Where the ICW joins or leaves another channel, the shape of the yellow mark may change to indicate this. But if you are traveling at night, you may encounter a lighted buoy or mark indicating a split channel. The light sequence Fl (2+1), a g light showing two flashes, a short break, then another flash, is reserved solely for split channels. Though these are used in the ICW, a split-channel mark closer to home can be found where the Trinity River channel leaves the Houston Ship Channel. 'Me color of a split-channel light reflects the buoyage in the main channel while the sequence (2+1) indicates the light should be left on the opposite side if you want to use the secondary channel. In order to know exactly what to do, you will still need to refer to a chart! Next month, I will continue with the navigation rules and using the VHF radio while in the ICW.
