This is a working commercial waterway, and it runs like one. The water is a managed pool rather than a tide, so the level under you answers to a dam somewhere and not to the moon. The channel is the navigable width, and a loaded tow coming the other way needs the whole of it. The passage is broken into pieces by locks, which means the clock on a day out here belongs partly to somebody else. And the thing most likely to end a run early is not under the keel at all. It is the wire or the span over your head.
Helm builds a separate pack for this river. It carries 1,224 charted depth areas and 1,203 depth contours, 88 bridges and 65 overhead cables, 100 charted lights and 11 charted lock features, along with 3 charted obstructions, 3 charted wrecks and 6 restricted areas. The whole pack downloads at 2 MB and works with no signal once it is on the phone.
Helm builds a river pack for fifteen US waterways. On the figures that describe how closely the bottom has been drawn, this one leads them. 1,224 charted depth areas is the highest count of the fifteen. 1,203 depth contours is the second highest. The two figures sit 21 apart.
That near match is the interesting part. A depth area is a patch of bottom the chart assigns a depth range to, and a contour is a line of constant depth, which in practice tends to run along the edge of one of those patches. When a waterway carries almost as many lines as patches, the good water has been given a shape rather than a general assurance. On the screen you can see where the usable width stops and how fast it gives up as you work toward the bank, which on a river with a maintained channel is most of what you want to know.
The marks are a different story. 100 charted lights puts this river thirteenth of the fifteen. The bottom here is described more thoroughly than the banks are lit, and a skipper planning to be out after dark should weigh those two figures against each other before deciding how far to push.
| In the chart pack | Count |
|---|---|
| Bridges | 88 |
| Overhead cables | 65 |
| Charted lights | 100 |
| Lock features | 11 |
| Charted depth areas | 1,224 |
| Depth contours | 1,203 |
| Charted obstructions | 3 |
| Charted wrecks | 3 |
| Restricted areas | 6 |
Counted from the Helm chart pack for the Black Warrior-Tombigbee, built from the official inland electronic navigational charts published for it. The pack downloads at about 2 MB. Lock features are counted as the chart draws them, with chambers, gates and dams as separate objects.
88 bridges and 65 overhead cables come down in the pack. Put them together and there are 153 charted crossings on this one waterway. The bridges rank tenth of the fifteen and the cables rank seventh, so of the two it is the wire that makes this river distinctive.
A bridge announces itself from a long way off. There is a structure in the windshield, and if it opens there is somebody to raise on the radio. A cable is a line against a bright sky that you may not pick up at all until you are underneath it, and nobody tends it. Sixty five is well past the number a person keeps in his head, which is the argument for having them on the chart in front of you rather than in memory.
If you carry a mast, or a flybridge with an antenna standing up on it, the figure that decides your day on this river is the one over your head rather than the one under the keel. Set your air draft in Helm once and the charted vertical clearance gets checked against it on every crossing. Worth remembering as well that a pool is a managed level, so the clearance you ducked under comfortably last month is not a promise about the same span this week.
The pack carries 11 charted lock features. That number counts objects the way the chart draws them, and the chart draws chambers, gates and dams as separate things, so it is not a count of lock and dam sites on the river. Among the thirteen river packs that carry any lock features at all, 11 puts this one eleventh. Bankhead is one of the names that appears in the chart data here.
For planning purposes the useful thing about a lock is that it converts distance into schedule. A tow ahead of you sets your arrival time at the far end, not your engine, and a chamber out of service turns a comfortable day into an overnight. Build the run in legs that end somewhere you would be content to stop, and treat the part of the day spent waiting on a lift as time you never controlled in the first place.
Locks also change what the depth under you means. The pool is held at a level by the structure below it, so the same spot reads differently depending on what the dam is doing, and a drawdown puts the bottom closer than the last trip taught you to expect.
The chart names three obstructions and three wrecks on this river, and draws six restricted areas. Measured against the other river packs those are low counts: ninth of the twelve that have obstructions charted, thirteenth of fifteen for wrecks, thirteenth of fourteen for restricted areas.
A short list of charted hazards is not the same as an easy river. It means the things that will spoil your day here are mostly not objects that sit still long enough to earn a symbol. A tow swinging through a bend needs the channel you happen to be in. Debris comes down on a rise and goes wherever the current puts it. A bank that moved in the spring does not get a new chart the following week.
Which is why the 1,224 depth areas earn their keep. On water where the hazard inventory is thin, the shape of the good water is the part of the chart doing the real work, and it is the part you should be reading when you decide how much room to give a tow.
Every figure on this page was counted layer by layer out of the pack itself, which is built from the official inland electronic navigational charts for this waterway. None of it is an estimate. The download is 2 MB, small enough that there is no sensible reason to leave it ashore, and once it is on the phone the chart and the planning work without a signal.
The general question of where depth numbers come from, and how a route gets planned against your draft, is covered on its own pages elsewhere on this site. What belongs here is the river specific part: 1,224 depth areas, 153 crossings overhead and 11 lock features, which between them describe most of what this waterway is going to ask of you.
These counts describe what the pack carries, not the state of the river this morning. Charted data ages, pools move with the dams and a lock can be out of service. Keep a lookout, listen to the traffic and verify locally.
These counts describe what the chart pack carries, not the state of the river today. Charted data ages, pools change with the dams, and a lock can be out of service. Keep a lookout, listen to the traffic, and verify locally.
Yes. The pack carries 65 charted overhead cables along with 88 bridges, which is 153 charted crossings on this waterway. The cable count ranks seventh among the fifteen rivers Helm packs, higher than the bridge count at tenth, so the wire is the more distinctive of the two here. Set your air draft in Helm once and the charted vertical clearance on each crossing is checked against it, which matters on a river where the height over your head decides more passages than the depth under you.
The pack carries 11 charted lock features, and Bankhead is one of the names that appears in the chart data. That figure counts objects as the chart draws them, with chambers, gates and dams as separate items, so it is a count of charted features and not a count of lock and dam sites on the river. Among the thirteen Helm river packs that carry any lock features at all, 11 puts this one eleventh.
The pack covers the water inside a box running from 33.06667 north to 33.83127 north and from 87.02984 west to 87.71441 west, and it downloads at 2 MB. Inside that area it carries 1,224 charted depth areas, the highest count of the fifteen US rivers Helm packs, along with 1,203 depth contours and 100 charted lights. Once it is downloaded it works with no cell signal.
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