Issue: November 2011
NAUTICAL KNOW HOW: A Difference in Bottom Think





by John Page Williams
photographs by Ann Levelle, and John Page Williams

If you look closely at the picture of the workboat Becky-D on the opposite page, you'll see that the anchor set into the bow chock is not an item that is readily available from marine retailers like West Marine. It's a custom-made "Rock Hall anchor," much loved by Chesapeake anglers and charter skippers because it bites quickly into shell bottoms where fish like spot, croakers, and white perch congregate.

On first glance it looks like a standard fluke-and-stock anchor. But if you look more closely, you'll see that the stock (the crossbar at the opposite end of the shank from the flukes) is perpendicular to the flukes. This causes the shank to rotate as the anchor strikes bottom, making the fluke bite that much more quickly. This sort of anchor is cumbersome to store anywhere except a bow chock, and it doesn't hold well enough in mud or sand for a cruising sailboat or powerboat to rely on it overnight, but it serves its fishing purpose better than almost any other anchor type.

Looking at Rock Hall anchors on var-ious friends' charterboats got me to thinking about how differently Chesapeake anglers and cruisers think about anchors, chart-plotters, and depthsounders.


Anchors
Choosing an anchor is all about specific purposes. The overriding concern for the cruiser is finding an anchor to trust with the boat and her occupants when they are asleep, swimming, gone ashore in the dinghy, or otherwise not paying attention. The water must be deep enough for the boat to swing to changes in wind and current without grounding, which in the Chesapeake frequently means the bottom will be mud or a combination of mud and sand. The anchor must dig into that material and stay embedded reliably for a period of time that might run from overnight to several days. This sort of holding ground wants a "burying anchor" with plenty of surface area to hold against the bottom material, like a Danforth, CQR/plow, or Bruce, so it's no surprise to see them in catalogs, on store shelves and on bow pulpits. The cruising boat does not have to stay precisely in the same spot, but the anchor's rigging must prevent having the rode or chain foul or work the anchor free as tides or winds shift.

The angler, by contrast, will be awake and active while anchored, and so able to tend the boat if the anchor pulls free. And he or she may well be trying to position the vessel precisely on a small lump that is not much larger than the hull. In a situation like that, a quick bite is crucial to getting just the right position over that "spot on the spot." If wind and current are opposed at all, it may be necessary to place a second anchor to maintain that position. If the spot is larger and wind/current conditions permit, a useful trick is to set the anchor so the boat drifts back over it. Then the angler can turn the rudder (or the outboard lower unit) one way or the other, to swing the boat back and forth and stay with the concentration of fish. Often in these situations the bottom is shell-covered and the quick catch is important, favoring a "hooking anchor" like the Rock Hall type or, on a small boat, an old-fashioned grapnel hook.

Far from seeking cruisers' favorite kinds of holding grounds, we anglers often anchor around evil, anchor-eating places like wrecks. They require special tools and tactics--like placing your good anchor well away from the wreck, paying out rode to get into position, and then dropping a "wreck anchor" into the mess below. When I anchor my Whaler on the remains of the old B&A railroad bridge in the Severn, my wreck anchor is something entirely expendable--half a cinder block, for instance. I don't even risk losing line, because I attach it by way of cable ties, which will break way if the block snags. Yes, half a cinderblock and cable ties. It's not an elegant rig, but it's cheap, expendable and very effective.

Down in the lower Bay, on nasty (but fish-holding) rubble like the Cell, flounder sharpshooters use locally made grapnel anchors--rebar flukes welded to a central stock. If such an anchor hangs, the rebar will usually bend to free it, and you can bend the bars back into position for the next drop. Another trick is to attach the chain securely to the crown (the fluke end), and not so securely--by way of a cable tie--to the head of the shank, where the chain is normally secured. That way, if the anchor snags, the cable tie will break and the chain will now be attached only to the crown, and the anchor will, in theory, back out of its predicament. A commercial alternative is the SeaSense Mighty Mite, with a lead-filled shank and bendable aluminum tines.

By the way, if you're interested in the nitty-gritty physics and engineering details of anchoring, one great book is The Complete Book of Anchoring and Mooring by Earl R. Hinz (Cornell Maritime Press, 2001). Yes, Hinz is a cruiser, not an angler, but he really knows his stuff.


Electronics
Even when we're ashore and not on our boats, we often amuse ourselves with water-related tasks, like planning cruises or working on equipment. Marine manufacturers and mapping companies have provided the cruising community with all sorts of navigation software wizardry for the former task. Working with these tools--everything from electronic Notices to Mariners to Google Earth--cruising boaters can happily work away at dropping named waypoints into named routes and even "scouting" voyages by satellite. Much of the task in route planning, though, is concerned with the surface of the water--where channel markers direct the vessel, what shoreline markers and ranges may be useful, how currents run, and what the scenery will be. Water depth is important, of course, but the charts generally indicate where it is adequate, supplemented by Notice to Mariners. The primary concern with bottom composition is holding ground for anchoring overnight. 

By contrast, we anglers are obsessed with any tiny details that our paper and electronic charts can tell us about bottom features, from little channel-edge shelves that may indicate oyster reefs to wrecks and lumps that may attract fish because of the communities of critters that grow on them. Or they may simply create current turbulence that improves dissolved oxygen conditions. 

After living on and carefully studying the Severn River for more than 35 years, I have been amazed by all the things my Navionics Platinum Plus chart card has taught me about that short river's bottom. On the Severn and many other waterways feeding the Bay, fishing is often a game of feet--even inches on the remnants of the railroad bridge I mentioned earlier. Anglers use charts and satellite-differential GPS for precision positioning, which we often complement with visual ranges and, of course, our quick-grabbing "hooking anchors."

Do anglers use routes? Yes, but only for traveling from the harbor to far-off starting points or for long passages from spot to spot. Far more often we often drop anonymous GPS "marks" on specific spots within productive general areas that we know, especially when we get strikes or see fish on our depthsounders while drifting or trolling. We frequently turn on our units' track feature, to see if there is any pattern to where we are finding fish. Over time, this practice of dropping marks and leaving tracks can clog up a memory card, so it pays to weed them out from time to time.

Cruisers and anglers use depthsounders very differently too. The former almost always want only a digital indication of depth, to avoid grounding. Other details are irrelevant. For an electronics manufacturer, designing this feature is not as simple as it appears, since the receiver must distinguish the bottom echoes from among many others that may represent dense fish schools, wrecks, and even bridge pilings that the unit "hears" at the sides of its cone of sound. In the Chesapeake, a dense school of menhaden passing under the hull can cause a digital sounder's display to jump from, say, 60 feet in a main channel to 10 feet (also causing the skipper's heart to skip a beat), because the fish are so tightly packed that the sounder's software reads them as the bottom.

We anglers, though, want the largest screens we can afford and fit at our helms, with good digital algorithms to "listen" carefully and filter out "noise" (plankton blooms and water turbulence, etc.) while still showing smallest details, like individual fish lying belly-to-the-bottom. And we use gradations of color based on signal reflection (echo) strength to judge bottom composition. Those dense bait schools that confuse digital sounders are important to us, because the details of the display can tell us whether there are predator fish lurking around them or actively feeding on them.

Today, many of us are also running dual-frequency systems from Lowrance and Humminbird, which use conventional sonar at 200 kHz and 800 kHz "downscan" and "sidescan" to integrate very thin slices of the water column into super-high detail. Detail? Yes, a four-panel electronic display (GPS/chart, conventional sonar, downscan, and sidescan) can be overwhelmingly confusing at first, but with time, it becomes a fascinating tool for an angler. It is a rich, three-dimensional view that can deepen anyone's understanding of the Chesapeake. Some of these units even allow us to record both sonar images and fishing tracks on memory cards, for later review.

In the end, for both cruisers and anglers, boating becomes a fascinating, challenging exercise in integrating old skills like anchoring and using visual ranges with modern electronic wizardry. Aren't we fortunate to be able to exercise our minds in these ways?