Wi-Fi Sonar Logging

No waterway is too small, nor too remote, for this clever sonar-logging system.

What if your plotter left not only a track line where you've been, but also depth contours provided by sonar?

Marine Wi-Fi technology has some clear utility for owners of large vessels. Say you’re down in the crew cabin, and you want to look at navigation data or a camera view of the cockpit. No sweat. With a network Wi-Fi hub, such as the Simrad GoFree or Raymarine RayControl, you can turn your phone or tablet into a remote Multi Function Display that lets you look at, and even control, your chartplotter, camera—or anything else that runs through your network.

For those of us on trailer boats, accustomed to simply leaning over and looking at the console, this kind of technology is a bit of a head-scratcher. Maybe it would be neat to see your sonar on your smart phone from a T-top spotting tower? Or from the bow, while dropping a jig? Or check your speed and water temp from the poling platform of a skiff?

Big potential in a small package with this unit.

Oddly enough, it’s at the microskiff and cartopper level where another tantalizing possibility is coming to light.

Among the small-but-growing field of Wi-Fi sonar device manufacturers, Vexilar’s SonarPhone T-Box system ($140) pairs a transom-mount, 200/83 kHz transducer with a small, 3- by 4-inch Wi-Fi box. It’s a 12-volt system requiring an accessory battery (marine, car, motorcycle, etc). You mount the T-Box and the transducer, run the cables, download the free SonarPhone app, and voila—you’re marking fish on your phone or tablet. It works to about 240 feet.

For owners of small boats or “backyard” rigs, it’s not hard to see the allure—there’s no head unit and screen to clean or worry over. You’re bringing your smart phone with you, anyway; probably going to pull up weather radar, take pictures, text home now and then. Why not make it the center of your whole compact network?

For a few years now, Navionics, the international charting firm with a U.S. office in Wareham, Mass., has been exploring “community” updates of marine and freshwater navigation charts, in the form of SonarCharts.

Sonar data recorded on a plotter combo may be uploaded at home to the Navionics site, and then the user may download an updated chart. This has the potential to fill in bathymetric details on government background charts, or update after storms, dredging and other events. Lowrance has a similar program, Insight Genesis, and Humminbird has AutoChart.

Navionics, of course, also happens to be in the apps business. The Navionics Boating app ($10 for phone, $50 for tablet) lets you navigate with a mobile device using the same kind of chart data that’s available on a full-featured chartplotter. And, the Navionics designers have teamed up with Vexilar to offer an interesting synthesis of technologies.

A SonarPhone/Navionics combo enables live updates to the SonarCharts mode immediately and automatically. While you’re watching the Navionics background chart on your phone or tablet, the Vexilar sonar is delivering bathymetric data, and new contour lines appear on the chart as you motor along. The contour lines are 3-foot intervals, at present, but smaller intervals are coming soon, says Navionics National Sales Manager Paul Michele.

Lake Ida peacock bass caught at a culvert indicated by the green icon on the chart above.

At present, the sonar data you record will be available to Navionics to distribute to other users. As with most everything in the digital world, you’re watching it—and it’s watching you. If you prefer to keep your log to yourself, you'd need to avoid connecting to Navionics again. Michele also says an “opt-out” feature is in the works.

Michele showed me the system on Lake Ida, in Palm Beach County. He had the Vexilar transducer bolted and siliconed to his Pelican Bass Tracker. For a viewing screen, we used Michele’s iPad. This tablet, of course, is a little tricky to read in bright sunlight (one argument in favor of fixed-mount, marine chartplotters for most vessels).

The system extrapolates depth contours in your vicinity, based on what’s picked up by the cone-shaped transducer signal beneath your vessel. If you pass through the area again, perhaps motoring over a brushpile or small reef, SonarCharts will update the contours accordingly.

Looking for peacock bass and largemouths, Michele and I relied on our usual topside references to locate fish. As it was late summer, we found fish at drainage culverts, surely awaiting the afternoon runoff. One culvert in particular produced two fish for us and some major blowups.

I wasn’t paying much attention to the depths—but the Vexilar was, and the Navionics app dutifully recorded its data. As we headed back for the ramp, I looked at the iPad and noticed a deep contour line swinging in close to shore next to that culvert. When we’d started out, the basemap had no bathymetric data for Lake Ida. By day’s end, we not only had a few GPS waypoints for catches, but also a keen view of where fish might be hanging out.

Vexilar’s SonarPhone lineup also includes a T-Pod wireless transducer ($129.95) which may be cast or trolled. Michele showed me screen-capture images of a trout stream in Oregon—he’d floated the T-Pod through the runs, rendering a permanent and useful picture of depth contours in stretches of water inaccessible to boats. FS

First published Florida Sportsman December 2014