The Gulf side of Florida runs from Boca Chica Key in the south up to Bald Point on Ochlockonee Bay, and almost none of it is deep. The water shoals a long way offshore, the bays behind the barrier islands are wide and thin, and the way from one to the next is usually a cut that somebody dredged and marked. Local knowledge on this coast is mostly knowledge of marks. Which pair you line up leaving the pass, which side of the point the sand went this year, where the green run ends and you are suddenly in two feet of grass. A chart that flattens all of that into plain blue water is not much help here.
The Helm pack for the Florida Gulf Coast is built from 168 official NOAA ENC cells and carries 115,701 individual charted soundings, 21,951 charted depth areas and 22,810 depth contours. Both of those last two counts rank fifth among the 18 US regions, and they work out to roughly 130 separate depth areas for every cell in the pack. That is what a coast with this little relief looks like once it has been charted properly, with the water described in many small pieces instead of a few broad zones. The whole pack downloads at 25 MB.
Of the 18 US regions Helm builds packs for, this one carries the most lateral beacons by a wide margin: 7,440 of them, against 726 lateral buoys. About ten fixed marks for every floating one.
That ratio is the Gulf coast in a single figure. A beacon is driven into the bottom and stays where the chart put it. A buoy rides a chain, swings with the current, and after a hard blow may not be where it was last month. Here the marks are the channel. You run pile to pile across a flat that reads the same shade of green in every direction, and the charted position of the next mark is a position worth steering to.
Six safe-water marks for the entire coast is the other half of that story. Nobody brings you in on a fairway mark offshore of the pass. You are brought in by pairs of laterals, and the 2,443 charted lights are what make the same runs possible after dark.
| In the chart pack | Count |
|---|---|
| NOAA ENC cells | 168 |
| Charted soundings | 115,701 |
| Depth areas | 21,951 |
| Depth contours | 22,810 |
| Lateral buoys | 726 |
| Lateral beacons | 7,440 |
| Charted lights | 2,443 |
| Anchorage areas | 34 |
| Bridges | 1,269 |
| Overhead cables | 784 |
| Dredged areas | 1,465 |
| Charted wrecks | 874 |
| Charted obstructions | 4,659 |
| Underwater rocks | 1,686 |
| Restricted areas | 553 |
| NOAA tide prediction stations | 211 |
Counted from the Helm chart pack for Florida Gulf Coast, built from official NOAA electronic navigational charts. The pack downloads at about 25 MB.
Only two of the 18 regions carry more charted dredged areas than this one. The depth attached to those 1,465 areas in the chart itself has a median of 7.8 m, about 25 ft. The deepest reads 15.5 m and the shallowest 0.3 m, which is a foot at datum.
That spread is the thing to take from the number. A dredged area on this coast can be a commercial ship channel or the entrance to a residential canal, and on screen both are the same kind of polygon until you read the depth written into it. Helm reads it, and shows the survey date and the chart's confidence grade beside the sounding, which matters more inside a maintained cut than anywhere else, because a cut is the one place where the bottom is expected to change between surveys.
Because so much of a passage here happens inside a cut, the useful question is rarely how deep the bay is. It is whether you are still between the lines, and how much water the line you are in was charted with.
The chart for this coast carries 874 charted wrecks, 4,659 charted obstructions and 1,686 underwater rocks, plus 553 restricted areas. The proportion is worth reading before the totals are. Obstructions outnumber wrecks better than five to one, so the thing you plot around on the Gulf coast is usually not a shipwreck. It is whatever else got charted as a danger on the bottom, in water shallow enough that it matters to a boat your size.
There are also 233 charted marine farming areas, the third highest count of the 16 regions that have any. Between those and the restricted areas, a fair amount of this water is water you are meant to go around rather than through.
On a flat where the depth barely changes for a mile, going around costs you almost nothing, so the habit that pays here is to route wide and early instead of trimming the corner. Helm plans against the draft you entered and reports the shallowest point on the line before you commit to it. On water this flat, that point is often somewhere the shading gave you no reason to expect.
NOAA publishes tide predictions for 211 stations inside this region, which is dense enough that the station Helm uses is usually close to where you asked.
That density earns its keep on this coast. The height at Anna Maria Key city pier is not the height at Bradenton up the Manatee River, and neither of those is the height at Ballast Point in the top of Old Tampa Bay or at Apollo Beach in Hillsborough Bay. These are shallow bays fed through narrow passes, so the further inside you are, the later the tide arrives and the more it is damped on the way. Small creek stations such as Aripeka on Hammock Creek exist for exactly that reason.
Helm names the station it used, so when you are timing a pass on the ebb or working a flat that dries, you can see whether the figure came from the gauge at the pier or from one well up the river.
The cable count ranks fifth of the 18 regions, and both numbers come from the same fact about this coast. It is threaded with canals and causeways, and most of them carry something across the water. The Cape Coral Bridge and the Boca Chica Channel Bridge are two of 1,269 charted crossings.
For any boat with air draft, that changes what planning means here. The bottom stops the deep boats and the crossings stop the tall ones, and on a coast with 784 overhead cables charted, the second constraint shows up more often than most skippers coming from open water expect. Helm checks charted vertical clearance against the air draft you entered as part of the same plan that checks the depth.
These counts describe what the chart pack carries, not the state of the water today. Charted data ages, channels shoal and marks move. Keep a lookout and verify locally.
The chart for this region carries 7,440 lateral beacons against 726 lateral buoys, about ten fixed marks for every floating one, and that is the highest beacon count of the 18 US regions Helm builds packs for. Shallow marked channels through flats and passes get piles, which stay put, rather than buoys, which swing and can move in a blow. The same coast has only 6 safe-water marks, so you are almost always navigating by pairs of laterals rather than by a mid-channel mark.
Yes. The pack covers the Gulf side from about 24.5 degrees north up to 30.4 degrees, so it takes in Boca Chica Key, Big Coppitt Key and the Waltz Key Basin at the south end and runs up through Charlotte Harbor and Tampa Bay to Bald Point on Ochlockonee Bay. There are 211 NOAA tide prediction stations inside that box, and the whole thing is a 25 MB download for offline use.
The chart carries 1,465 dredged areas for this region, the third highest count of the 18 US regions, and the charted depth in them has a median of 7.8 m, roughly 25 ft. The deepest reads 15.5 m and the shallowest 0.3 m, about a foot at chart datum. Helm shows the figure for the specific cut you are in along with its survey date, since a commercial ship channel and a canal entrance look the same on screen until you read the depth attached to each.
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