The Ohio runs as a sequence of pools. Each pool is held at a working level by a dam, and you get from one to the next through a chamber, so the trip is broken into pieces by structures that were built for barge traffic rather than for you. Between the structures the useful width is a channel that a loaded tow needs all of, and a tow cannot hand it back because a recreational boat has arrived. What stops a boat on this river is more often over its head than under its keel. That is the part people coming off salt water get wrong. On a coast the number you watch is the depth, and here the number you watch is the clearance.
Helm's Ohio River pack carries 734 charted bridges and 186 overhead cables, the highest bridge count and the second highest cable count of the fifteen US rivers Helm builds packs for. It holds 1,793 charted lights and 134 charted lock features covering chambers, gates and dams. Under the waterline it carries 556 charted depth areas and 1,103 depth contours, with 239 charted wrecks, 45 charted obstructions and 60 underwater rocks. All of it downloads as one 10 MB pack and works with no signal.
Helm builds chart packs for fifteen US rivers. The Ohio comes first on four of the counts, and those four have something in common. Every one of them counts a fixed thing. Bridges, lights, wrecks and lock features do not drift with the season. A bay takes its character from water that moves around, and this river takes its character from structure that stays where it was put and from a channel running between the structures.
First in charted lights at 1,793 and first in charted wrecks at 239 describes the same river twice. Traffic works this water at night and works it through the year, so the marking is fixed, lit and kept up. Traffic that heavy over that long also leaves things on the bottom. The depth side of the pack sits high without leading: 1,103 depth contours puts the Ohio third of the fifteen and 556 charted depth areas puts it fourth.
| In the chart pack | Count |
|---|---|
| Bridges | 734 |
| Overhead cables | 186 |
| Charted lights | 1,793 |
| Lock features | 134 |
| Charted depth areas | 556 |
| Depth contours | 1,103 |
| Charted obstructions | 45 |
| Charted wrecks | 239 |
| Restricted areas | 48 |
| Underwater rocks | 60 |
| Anchorage areas | 1 |
| Lateral buoys | 1 |
Counted from the Helm chart pack for the Ohio River, built from the official inland electronic navigational charts published for it. The pack downloads at about 10 MB. Lock features are counted as the chart draws them, with chambers, gates and dams as separate objects.
Add the 734 bridges to the 186 overhead cables and the pack holds 920 charted things to pass under. A skipper in a low open boat can read that as trivia. Anybody running a flybridge, a radar arch, an antenna left standing or a mast is looking at the binding constraint of the entire river, and it is worth knowing the figure for your boat to the inch before you leave rather than working it out while you close on a span.
The cables are the harder half of the number. A cable does not open, and there is nobody standing by to answer a call about it, so the charted vertical clearance is the whole of the negotiation. Set your air draft in Helm once and the charted clearance gets checked against that figure on every one of the 920 crossings.
One thing belongs in the front of your mind on a river that does not apply on a bay. Charted clearance is measured against a reference level, and the river does not sit at that level all year. When the water comes up, the gap comes down. The printed figure is where you start the arithmetic, and the rest of it is whatever the river happens to be carrying that week.
The pack carries 134 charted lock features, which is first among the thirteen rivers Helm charts that have any at all. That number counts chambers, gates and dams as separate features. It describes how much structure is drawn on the chart, and it should not be read as the number of lock sites on the river.
Named chambers inside the data include Emsworth, Greenup, Markland and Cannelton. There are more names than those four, and there are spelling variants among them, which is the other reason the honest figure is a count of features.
What the chart hands you at a structure is its shape before you can make it out on the water: which side the chamber sits on, where the gates are, and where the dam runs across the rest of the river. That is worth having at a distance. Sorting out a dam visually at the last minute is not a position anyone wants to be in, and commercial tows get worked through ahead of recreational boats, so a day plan that assumed a quick lockage is a plan that needs slack built into it.
The Ohio carries more charted lights than any of the fifteen rivers, 1,793 of them, and the pack holds a single lateral buoy. That ratio is the marking system in one line. This river is marked from the bank and from the fixed structures. There is no floating line of aids to follow from one to the next the way you would across a buoyed bay.
It changes the habit you run with. On a bay you go mark to mark and the marks tell you where the channel went. Here the lights tell you where the bend is and which side of it belongs to you, and in between you are reading the water and the bank. The marking is lit as heavily as it is because towboats work the river through the night, and a system built to be read from a towboat pilothouse in the dark is a generous one to run a small boat by.
Alongside the 556 charted depth areas and 1,103 depth contours sit 239 charted wrecks, 45 charted obstructions and 60 underwater rocks, the rocks putting the Ohio third among the six rivers that have any charted. The ratio of wrecks to obstructions, better than five to one, tells you what kind of hazard this water makes. Most of what is flagged here arrived by sinking rather than by being part of the ground, and a hull that went down in a working river went down where the working river runs.
The pack also carries 48 restricted areas, fourth among the fourteen rivers that have any, which is what this much industrial waterfront and this much lock approach produces. And there is exactly one charted anchorage area, the only one on any of the fifteen rivers. Wherever you plan to stop for the night on the Ohio, the chart is not going to hand you a box to sit in.
Where the depth figures come from, and how a route gets planned against the draft you entered, each have a page of their own on this site. On this river they are the second question. The first one is overhead.
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.
734 bridges and 186 overhead cables, which is 920 charted crossings in all. The bridge count is the highest of the fifteen US rivers Helm builds packs for and the cable count is second. Set your air draft in Helm once and the charted vertical clearance on each crossing is checked against that figure. Keep in mind that charted clearance is measured against a reference level, so a river running high gives you less room than the printed number.
Yes. The pack carries 134 charted lock features, first among the thirteen rivers Helm charts that have any. Chambers, gates and dams are counted separately inside that figure, so it describes the structure drawn on the chart rather than the number of lock sites on the river. Named chambers in the data include Emsworth, Greenup, Markland and Cannelton, and there are more names than those. You can see which side the chamber sits on and where the dam crosses well before the structure is in sight.
Because the river is marked with fixed lights instead. The pack holds 1,793 charted lights, the highest count of the fifteen US rivers Helm builds packs for, against that single lateral buoy. Running the Ohio means reading lights on the bank and at the structures rather than following a floating line of marks, and the marking is lit that heavily because towboats work the river at night.
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