When it comes to fish-finders the ability to see off to the sides is awesome, and the newest form of sideways-scanning fishfinders has just been announced: Garmin SideVu, via the GCV 10 sounder. Looking down in high-res is another new Garmin ability, with the DownVu dv series fishfinders.
Like other offerings in this class, the Garmin systems utilize very high frequency, fan-shaped sonar beams. Most systems shoot out these beams in the 455/800 kHz range, to draw a detailed picture. In a nutshell, these higher frequencies—which are more than double the frequency commonly seen in traditional down-looking sonar—have much better sensitivity and thus provide more detail, though their range is severely limited.
An easy way to conceptualize the difference is to think of sonar waves as the waves you see on a pond. If you throw a big rock into the pond it creates large waves, they’ll travel quite far, and may roll right over small items. Larger items, however, will bounce those waves back. These are similar to low frequency sonar waves. On the other hand, if you toss a pebble into the pond, it will create a series of much smaller waves which can’t travel very far, but are reflected back by the tiniest of objects. These are your high-frequency waves. Net result? High-frequency side finders and down-imagers can show sprigs of weed or the individual branches in a tree, and paint an extremely detailed picture of what lies off to the sides or beneath the hull of your boat. As a rule of thumb, however, range is limited to 150' in the best of conditions and can be significantly less in some situations.
The Garmin SideVu system will come via the GCV 10 black-box sounder, which is based on the CHIRP-equipped GSD 26 black box. Naturally, to get SideVu (or DownVu; the GCV 10 is capable of providing either or both) you do need to add another transducer or two into the mix. Or, if DownVu is what really interests you, Garmin will have a line of lower-cost dedicated down-looking units (the echo dv series) hitting the market by the end of this year.
As soon as these goodies are available, I’ll try to get in some water-time with a SideVu and DownVu system, and report back. But if history is any indication, these fishfinders are going to be a ton of fun to play with—and should certainly lead to more fish in the box.
For more information, visit Garmin.