Sea Savvy - Beyond the chart plotter

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As great as today’s electronic gear is, an experienced eye remains your most reliable navigational tool

As great as today’s electronic gear is, an experienced eye remains your most reliable navigational tool

When I first started “yachting” I had no trouble finding my way; I just followed the rope. I was 9, and my parents wouldn’t let me untie from the shore. At least they gave me a long rope.

 

At that point I was just learning to row. I soon became skilled at the art, and they cut me loose (in a manner of speaking). But I still didn’t have much trouble figuring out where I was. I quickly learned to row only on the mud flats at the end of town where there wasn’t much current. In these limited geographical confines, I could always see the shore and the beach where I kept my boat. If I left those flats, I would quickly get into so much current that I didn’t have to know how to find my way, because I wasn’t going there anyway. I was going with the tide, and that was either upriver or downriver until it turned and brought me back again.

Later in life, after graduating to an outboard, I found an old gimbaled compass in a box that had washed up on shore after a storm. It was near a little, old steering wheel with wooden spokes, like in the pirate movies. The combination of the two got me into a lot of trouble over the years. I rigged the wheel to the backside of the cabin I’d built on my 18-footer, and screwed the compass to a little shelf. No, I didn’t compensate the compass, because I didn’t know that you could or what the point of doing it would be, anyway. I knew that north was up the river (kind of) and that the big arrow pointed up the river (usually), and that seemed good enough for me.

I loved steering with a real “ship’s” wheel, and that’s what I’d do, reassured with the thought that I could use the compass to get back if I forgot whether I’d gone up- or downriver. The only problem was that during the few times I did use the compass, I found that steering to it was what they must have meant in the seamanship books when talking about the Great Circle Route.

As life went on and my rope grew ever longer, I ventured all the way down the river and saw the awesome expanses of Chesapeake Bay. Now this was a place where I could get lost. But with the help of my old Esso map, and the fact that it didn’t make much difference if I ran aground because I could just get out and push, I began to learn some real navigation skills.

I learned to hug the shoreline. In doing this, I learned that in the warm months crab pots were usually set along the drop-off from the shallows to deeper water. I learned to ask around until I knew about shoreside landmarks, because the little drawings of lighthouses and such on the Esso map didn’t look much like anything out there. And I learned to hug the shore and then take off from a known point on shore that was closest to an unseen destination “somewhere over there.” After a few longer-than-expected trips to nowhere, I found this was far better than just taking a straight line into the middle of the Bay to achieve the so-called “shortest distance between two points.”

My greatest feat of navigation at that time was to find TangierIsland, which to me was really far away and really far out. I found it, although I wasn’t sure until I worked my way up into a creek and asked someone. The guy wanted to know why I was asking, since I was already there. I told him where I’d come from, and he looked at me like I was the craziest kid he’d ever seen. Coming back, I learned that it’s always easier to find a coast than an island. And I learned that if I wanted to be sure to get back to my river, I needed to steer so I knew I’d hit the shore before I missed the river.

By the time I’d graduated to a 41-foot sailboat I got one of those depth finders you built from a kit. The needle would spin around and around, and a little light would flash when it passed the appropriate depth mark on the dial. I thought this was about as far as I could go in electronic technology without joining the Navy. To know how deep the water was without running aground was an experience I never would have dreamed of a few years before.

Reading the water

This was the height of my navigation technology until we took off for the Bahamas in our 47-foot motorsailer with our two very young daughters aboard. Also aboard were a radar, single sideband radio, two depth finders, a state-of-the-art Loran, a sextant and a radio direction finder. The Loran should have clued me in to what was coming around the corner in the not-too-distant future, but I wasn’t very impressed with it after we got away from the coast.

We once saw a magnificent trawler in the Bahamas carefully follow Loran coordinates into a cut that wasn’t a cut. Locals on the island told him over the VHF that it wasn’t a cut, but he told them that his Loran said it was. He ended up on a reef between the wrong two islands. The reef was shallow enough to walk across at low water, but at high water the seas were washing through the guy’s main saloon, having smashed its large windows.

This was in the days when you’d be halfway across the Gulf Stream, plugging along making about 2 knots over ground, looking at your compass and hoping you’d make it to the other side before it took you to the Grand Banks. Invariably a fast powerboat would zoom alongside, slow down and the crew would yell across the water, “Hey Buddy, which way to Bimini?” You’d point, and the boat would take off until they got to the next sailboat, when they’d stop and ask again. Later, I realized they knew a lot more than I did. This was just their way of taking waypoints.

After a few winters in the Bahamas, we observed a strange phenomenon. We were anchored in South Florida’s Biscayne Bay, waiting to take off for the Bahama Banks the next morning. We’d been hearing about something called GPS and units that you could hold in your hand. We’d seen in the magazines that you could even get one for around a thousand bucks from Magellan that would bounce, float and tell you where you were with only the push of a few buttons and lots of double-A batteries. But we didn’t have one. We were too busy spending all our thousand-

dollar bills on health insurance for our little ladies and home-schooling books and things like that.

To get out of our anchorage area in Biscayne Bay you either had to backtrack to the deep and wide Government Cut or go through the Florida Channel around the south end of Key Biscayne. This was a tricky, shallow passage through shifting sandbars with ocean swells breaking on them. We would wait until good light to go through, because then we could read the water. As evening approached, three dinghies moved out from the anchored fleet, heading to the Florida Channel. Mel and I looked at each other in amazement — what were they doing?

We heard one call another on a hand-held VHF and followed as they switched to a working channel. It soon became clear. They were looking for shoals in the passage and writing down the coordinates. They planned to find their way out in the dark. As we made coffee the next morning, we heard them head out in their sailboats, following the coordinates. Two went aground briefly, and one almost went aground, but they all got through using the old bump-and-grind technique.

We heard the group doing the same thing later in the Exumas, where reef awaited the keel instead of sand. This was in the days when you were sometimes lucky to be within a half-mile of where the GPS said you were. We wondered if they even thought about learning to read the water. We didn’t realize that things were to get much worse.

Now we regularly see sail- and powerboats plowing across the ocean or over the Bahama Banks, making precise turns at waypoints, sticking to an imaginary line across the water. Often there’s no one in sight at the wheel. In the waterways and in the Intracoastal Waterway in particular, we regularly see boats speeding down the narrow channels. Yes, there’s someone at the wheel, but all too frequently they’re looking down at a screen, meticulously trying to keep their boat’s icon on a magenta line. If the screen doesn’t refresh fast enough they start pushing buttons rather than look up ahead. This happened recently when a very nice yacht missed the channel near us and ran up on a hard-sand shoal that’s bare at low water and identifiable at high water from many conspicuous clues.

We recently were riding with the TowBoatU.S. operator who covers Ponce de Leon Inlet (Ponce Inlet) in northern Florida. He pointed to the side of the northern channel that leads to the inlet and to a sand shoal with a deep slough between it and the marshy shore. He told us to look very closely at one end of that slough, and we saw a bit of a metal loop protruding from the bottom in just a few feet of water. We would have never noticed it if we hadn’t been told. It was the tip of the rail on the bowsprit of a sailboat. The sailboat, including mast, was nowhere in sight.

“It’s beneath the sand,” we were told. It had dragged anchor in a storm and grounded. The owner hadn’t gotten it off, and soon the sands, ever washing on the strong currents, began to cover it. The water dug around its hull, which settled into the sand of the building shoal. Now you see just the tip of that rail.

We’ve seen this in other areas. In St. Andrews Sound in Georgia, a commercial shrimp boat found a shoal just at the inner turn of the inlet. By the next year, only its masts were above the sand, with the rest of the hull buried. Some day in a storm those shoals may erode, and both of these boats may arise like skeletons of the past, waiting to grab an errant boat and begin the cycle again.

GPS isn’t precisely exact to begin with. And shoals shift. They can shift dramatically in just one storm, or if a large boat or barge goes aground and remains stuck for a while. We’ve had occasions while traveling the ICW where we had to pass on the wrong side of an aid to navigation in order to find water deep enough to get past. And floating buoys and other nav aids are regularly changed in many areas to reflect changes in the bottom. Sometimes they drag anchor to another spot. And even updated charts are sometimes based on much older charts that are a bit off here or there. We’ve seen entire islands that weren’t where they were supposed to be.

It’s also true that even the best navigation equipment can fail, and the boat’s supporting equipment, such as batteries and alternators, can experience problems that affect the end user at the steering station. Further, GPS was created for military use, and sometimes it is temporarily shut down. It isn’t unusual to hear a Coast Guard Notice to Mariners announcing that GPS for civilian use will be temporarily down in an area or that a satellite will be off line temporarily. Other factors, such as solar flares, may interfere with GPS accuracy.

Beyond the chart plotter

To safely navigate we should take full advantage of the remarkable electronic equipment that’s available today, but we also need to do far more than look at a screen. We still need seamanship skills that were tried and true before the age of fancy electronics. We need to be able to use them in conjunction with the incredible help we get from electronics and, when needed, on a standalone basis. Let’s look at some examples.

Making our way down the ICW in North Carolina last fall, we passed through the firing range at CampLejeune. At the southern end of the area an opening bridge blocks passage for most boats of any size. When the firing range is “hot,” guns boom and shells whistle over the ICW. During those times, of course, the waterway is closed to traffic. When we pass through we’ve seen signs on the shore admonishing boaters not to land because of the danger of unexploded ordnance. This is not one of those places you’d like to run aground.

This thought came abruptly to mind as sea fog that had been flirting with the coast suddenly swept inland. We were engulfed in wet, clinging, swirling mist so thick we couldn’t see from one end of the boat to the other, except for brief breaks in the fog. We did everything we could to stay in deep water and know how far away the bridge awaited, including watching the depth finder, compass and chart plotter, and standing lookout on deck to peer through the fog.

Several times we noticed the chart plotter indicating that we weren’t only aground but up in the marsh with the unexploded ordnance. We have an older unit and a new one made by different manufacturers — both good and both indicating the same anomaly. We knew we weren’t ashore, and we weren’t concerned with the functionality of the plotters. We’d seen this before and knew other boats experienced it from time to time, here and in other areas, especially where the ICW is a narrow, dredged cut. We knew we had to do more to navigate than look at a screen. But we did continue to check the screen, as well as doing the other things.

There were some areas of severe shoaling in the cut, some of which had been marked by temporary floating buoys. However, with the fog, we couldn’t see the buoys. We didn’t want to hit them or the shoals they marked. Even though the GPS occasionally had us off to the side of our actual route, we were able to tell from the chart plotter where we were in the cut well enough to know when we were approaching the shoal areas. This enabled us to find them by peering through the fog carefully at the right times. Without the chart plotter, we would have had to blindly guess.

Other boats stuck in the mud apparently had been doing just that, or looking only at the plotter without doing anything else. Luckily we saw these boats on radar and could tell with the plotter that there were probably no buoys at their location, leading us to the conclusion that there was a stuck boat up ahead that we needed to avoid. This also clued us in to when we should concentrate with binoculars. Our Steiner Commander XPs have a coating on the lenses that repels water, and we feel this helps with fog.

Using our electronic tools and simple, old-fashioned navigation, we finally neared the bridge at the southern end of the cut. This presented another problem. This bridge, like too many others, has restricted opening times. Never mind that your boat and perhaps crew might be imperiled from waiting in bad conditions; if we got to the bridge too late we’d have to wait in a strip of water that was too narrow in which to circle in the fog and almost too narrow to anchor. And if we got to the bridge too early we’d have the same problems.

We couldn’t see the bridge and couldn’t simply stop in the strong current. Anchoring in that narrow, shoaling channel would have presented hazards because of approaching boats. The radar showed the bridge but didn’t give us a very reliable ETA. The chart plotter was incredibly helpful with this, allowing us to adjust our already slow speed, compensating for current, long before we got to the bridge so that we could arrive at the right time.

To combine the old ways with the new, you have to know the old ways. The new is pretty simple. You push some buttons, and it’s done for you — if it all works well. The old requires a lot more learning, but it’s been saving people on the water for a very long time. And a few hours in a boating course isn’t enough to pick this up. It takes a lot of training and experience. You can find good examples of old tricks to merge with new right around home or farther away.

Crossing the Bahama Banks, heading for Nassau and more distant points, can be a perilous trip. For starters, you have to get on and off the Banks. It’s not just a matter of going from ocean to shallow waters. The Banks are ringed with coral reef. To enter or exit the Banks, you have to go through a cut in the reef. Missing these spots has meant the loss of many a boat and quite a few lives over the years.

Crossing from the east coast of Florida, the Gulf Stream flowing to the north can drag a slower boat in that direction at several knots. The speed varies with where you are in the Stream (it’s usually the most in the Axis), recent weather conditions (if there’s been a prolonged northerly or southerly), and whether you encounter some of the huge eddies that occur, particularly around the edges of the Stream. Despite this, you’ve got to find a precise spot to enter the Banks on the other side.

In the old days we would basically guess at the compensations we’d have to make in our courses, and use celestial navigation. When we reached the islands on the other side we’d have to recognize landmarks to identify exactly where we were or weren’t. We used guidebooks with photographs or drawings of landmarks, which weren’t easy like in the States. They weren’t tall buildings or sets of striped smoke stacks; they were small islands with humps in the middle or at the end, or cuts with a big rock to one side, or cuts with a small island inside sporting a lonely bush. When we figured we were at the right spot, we’d have to find our way through the cut by reading the water. This meant that we wouldn’t enter in low light or with light in our eyes, and often someone would be posted high up on the boat to better read the water.

Once safely on the Bank we’d have to follow a route across that kept us free of the coral heads scattered about. (Flying over the Banks, it’s amazing to see all the areas of hard brain coral and rocky ledge that can hole a boat.) The problem with this was that currents always washed across the Banks, varying in direction and speed with the tide and winds and moon phases. While we had some knowledge of the speed of the Gulf Stream from listening to reports and reading coastal pilot information, we had much less knowledge of how much we were being set, and in which direction, by the currents on the Banks. So we watched the sea grasses and fan coral.

The water there is clear enough to see the bottom in 20 feet or more. You can tell which way the current is running, and roughly how fast, by seeing which way sea grass and fan coral is bending and how much. We also watched the bottom for known characteristics, such as depth, color of the sand or rock, patches of coral and other clues.

For example, on the Banks between Nassau and the Exumas there’s an area of coral that’s shallow enough to hole many boats. The bottom looks yellowish compared to surrounding areas. We look for this, as well as a corresponding decrease in depth. Today the chart plotter helps immeasurably with this route, but it’s also important to observe as in the old days. Not only do you want to know how to handle things should something go awry with your equipment, you want to see those brain corals. They’re not plotted, even though the general area in which they’re located is. And you want to practice reading the water, because no chart plotter is good enough to rely upon exclusively to get you through an ocean cut with reef and rock and current ripping through.

There are navigation lessons for all areas, not just the Bahamas. Mark Twain wrote of the river pilots who could read the rivers like books. They could tell by swirls on the water that there might be a precipitous shoal or rock or tree stump below. They could tell by still waters that it might be very deep.

And birds give clues. They don’t walk on water, but they walk on shallow bars that are a few inches under the water. A river or creek flowing rapidly around a curve often will cut a deep channel on the outside as it rounds the bend, leaving a shallow bar where the current slows inside the curve and deposits mud or sand. These bars often extend more than halfway across the water, and you must hug the far side.

You can sometimes tell that they’re there because of the contour of the creek bank, the fact that current moves more slowly over them, and because of ripples or swirls where the current collides with their steeply rising slopes. A chart plotter probably would alert you to the shoal but would be less reliable as to the exact contours of the shoal because they change.

In the Northeast there are different problems. Fortunately, rocks don’t move like sandbars. Deep-water passages are pretty stable, and they’re usually better plotted than in remote areas. But there are enough rocks and rocky bottoms there to cause plenty of trouble. Seamen there have used many tricks of the trade over the centuries. For example, rocks can make quite an impression on the surface of the water. This may be breaking or splashing waves, whirling eddies, sounds of current ripping or sucking around them, or waves breaking on them. Also, you can often smell them when they’re above water.

I sometimes hear old-timers decry this modern navigation technology and moan for the good ol’ days. But it’s not the technology that’s the problem; it’s some of the people who use it. It’s the people who use it as a crutch rather than as another valuable tool. It’s the people who use it as an excuse to not learn navigation beyond looking at an icon on a screen. We think this high-tech equipment is great. It makes things much easier and adds to the fun of being out here. Far more importantly, it makes us much safer.

We have two GPS/chart plotters on board, one of which is 7 years old. The other is a Standard Horizon CP300i with an internal antenna and C-MAP Max cartography. I couldn’t believe the difference a few years made in the improvements in this type of equipment. If I won the lottery I’d buy completely new equipment every year or so. (You can easily update some chart chips, such as C-MAP Max.) We use our chart plotters and our depth finders and radar whenever we’re running. The older chart plotter lives below to give whoever is off watch a rough idea of what’s going on, and the new one is at the helm. But we also use paper charts, such as the ChartKits by Maptech and Explorer Charts for the Bahamas. We use our Steiner Commander XP binoculars with internal bearing compass to help see where we are with those old-fashioned tools known as eyes.

“Beyond the chart plotter” means back to the past, as well as out to the future. We combine the benefits of this equipment with all the tricks I began learning before I had ever dreamed of electronics on a boat. I’d hate to think of being out here again without a good plotter and all the other electronic goodies, but I’d also hate to be on the water without being able to do without them. And I look forward to what the technology of the future will bring to keep us safe on the water, before I reach the end of my rope.

Tom Neale is technical editor for Soundings and lives aboard a Gulfstar 53 motorsailer. You can buy his book, “All in the Same Boat,” at www.tomneale.com .