A river is a different problem from a bay, and the Atchafalaya makes the difference plain inside the first hour. The water is going somewhere and it takes you with it. The channel is working water, and a loaded tow coming through a bend needs the whole of it. Most of the day is spent reading the bank instead of the horizon. The thing that actually ends a trip here is rarely under the keel. It is fixed overhead, built to a height that owes nothing to your boat, and it will still be that height when you get there. The passage does not run continuously either. It comes in pieces, with a controlled crossing between them where your schedule quietly stops being yours.
Helm's Atchafalaya pack covers the river corridor from 29.67 N up to 31.02 N and downloads at 1 MB. It carries 30 bridges and 27 overhead cables, 75 charted lights, 60 charted depth areas and 35 depth contours. It also holds 25 charted obstructions, 10 charted wrecks and 44 restricted areas, and that last figure is a large one for a single river corridor.
Add the 30 bridges to the 27 overhead cables and the pack describes 57 charted crossings over this corridor. Nearly half of them are cable. That is the half worth planning around, because a cable has no tender, no opening schedule and nobody listening on a radio channel. The charted vertical clearance is the entire warning you get, and you get it in advance or not at all.
This is why the figure to settle before you leave is your air draft rather than your draft. Set it once in Helm and the charted clearance on each crossing is checked against it while the route is being planned. A skipper with a mast up, or a flybridge carrying an arch and antennas, is running a boat several feet taller than the one in the specification sheet. Measure from the water to the highest fixed thing on her, then write down what the outriggers do when they are up. Fifty seven crossings is fifty seven opportunities for the brochure figure to be wrong once.
It also changes what a detour means on this river. On open water you can usually go around the thing in your way. Here the crossing spans the whole channel, so a clearance you cannot make is not a diversion, it is the end of the run in that direction.
| In the chart pack | Count |
|---|---|
| Bridges | 30 |
| Overhead cables | 27 |
| Charted lights | 75 |
| Charted depth areas | 60 |
| Depth contours | 35 |
| Charted obstructions | 25 |
| Charted wrecks | 10 |
| Restricted areas | 44 |
Counted from the Helm chart pack for the Atchafalaya River, built from the official inland electronic navigational charts published for it. The pack downloads at about 1 MB. Lock features are counted as the chart draws them, with chambers, gates and dams as separate objects.
Helm builds chart packs for fifteen US rivers. Two of the Atchafalaya counts stand near the top of that set, and both of them describe things you have to steer clear of rather than things you can steer by.
There are 25 charted obstructions in this pack, fourth among the twelve river packs that carry any at all, and 10 charted wrecks alongside them. Two and a half obstructions for every wreck is the signature of moving water. Most of what will hurt you out here did not sink on the spot in one event. It arrived, it settled, and it settled in water you would otherwise cross without giving it a thought.
The other figure is 44 restricted areas, fifth among the fourteen river packs that have any. Put that beside the 60 charted depth areas in the same pack and you have a fair picture of how much of this river answers to somebody's rules. Restricted water on a river is usually a sign that something is being managed there, and managed water has a habit of sitting exactly where the passage narrows.
Planning a coastal day comes down to multiplying speed by hours. On this river that arithmetic falls apart. The passage is broken into pieces by structures you have to pass through, and at each one your progress stops being a function of your boat and becomes a function of whoever got there ahead of you. Traffic already working a chamber is a wait you neither control nor shorten.
So plan in pieces. Decide where you intend to be before dark instead of how far you intend to get, and treat every controlled passage as somewhere the day can lose an hour with no warning at all. Helm plans a route leg by leg and puts the distance of each leg into the sentence that explains it, so when a wait swallows the afternoon you can see straight away which leg you are giving up and which one you are keeping.
Commercial traffic takes precedence over your convenience whether or not the rule book says so, for the ordinary reason that a loaded tow cannot hold station in a current the way you can. Getting in line early and staying well out of the way is most of the technique. It costs nothing except the hour you should have planned for anyway.
A charted hazard does not survive long in the middle of a channel that commercial traffic keeps swept. What survives sits off to the sides, and off to the sides is precisely where a meeting puts you. That is the moment the 25 charted obstructions and 10 charted wrecks in this pack stop being trivia and start being the reason you slowed down early.
Know where the edge is before the meeting, not during it. The 60 charted depth areas and 35 depth contours the pack carries are drawn on the chart, and the 44 restricted areas sit on the same view, so the ground you are being pushed toward has some description attached to it rather than being blank water you are guessing at. How Helm handles the depth figures themselves is a subject in its own right and lives on the depth page.
The pack also brings down 75 charted lights. Dusk on a river arrives sooner than it does offshore, because the bank takes the light while the sky still looks fine. The marks you were reading by eye at five o'clock are the ones you need lit at seven, and being able to check which ones carry a light, rather than working it out from the shape of the bank, is most of what keeps the last hour of a run calm.
The Atchafalaya pack is 1 MB. Once it is on the phone, planning and navigation work with no signal, which matters on water where coverage comes and goes and where the bank is often between you and the nearest tower. Nothing about the route or the crossings needs to be fetched while you are running.
Helm builds packs for the Lower Mississippi River and the Red River as well, each downloaded on its own. At these sizes a trip that touches more than one river does not turn into a decision about storage. Take the neighbors too and sort it out on the water.
These counts describe what the chart pack carries, not the state of the river this week. Charted data ages, banks move, marks are relocated and a crossing gets rebuilt. Keep a lookout 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.
The Helm pack carries 30 bridges and 27 overhead cables for the corridor it covers, which is 57 charted crossings over your head. The cables are the ones to plan around, because a cable does not open and there is nobody to call about it. Set your air draft in Helm once and the charted vertical clearance on every crossing is checked against that figure while the route is being planned, which is a far better moment to learn about a tight one than the moment you are looking up at it.
The pack carries 75 charted lights and they come down with it, so they are on the chart whether or not you have a signal. Night work on a river is mostly a matter of knowing which marks are lit and remembering where the unlit ones were, so it is worth looking at those and at the 25 charted obstructions and 10 charted wrecks in the same pack before the light goes. A tow coming the other way will be lit as well, and it will want more of the bend than you expect it to.
Around time. A controlled passage can hold you for as long as the traffic already there takes to clear, and that is not a figure you can budget out of your own boat speed. The workable method is to decide where you will tie up before dark rather than how many miles you will make, then use the leg distances in the Helm route summary to see which leg you drop when a wait takes the afternoon. Arriving with daylight still in hand is worth more here than an early start is.
Helm Boating