Down Scanning Sonar Fish Finders: Our Buying Guide

Down scanning, down imaging, or down vision sonar technology is actually a step further from traditional sonar technology. It offers a superior quality view of the sonar return, and whatever passes underneath the boat will appear on the screen in a much clear detail than in traditional sonar imaging. This makes it much easier to distinguish between structure and fish and allows you to assess better, how far up in the water column a fish is situated.

There are several brands that offer fish finders featuring this type of sonar. So far, Lowrance, Humminbird, and Garmin are top of the list. But each one of these manufacturers offers a different palette of features surrounding the Down Imaging sonar technology. Also, even though this type of sonar pretty much works the same regardless of fish finder brand and unit, there are differences and specifics for each one.

The first aspect you must know about this sonar technology is that its terminology differs from a manufacturer to another. Garmin calls it ClearVü, Lowrance calls it DownScan or StructureScan, and Humminbird calls it Down Imaging. Regardless how it’s called, it’s basically the same thing. In this post, we’ll refer to it as DI, down imaging, or down scan.

How Does Down Imaging Work and How to Interpret It

First of all, a fish finder with Down Imaging or Down Scan requires having this technology built-in the head unit. Or the unit should be at least compatible with a sonar module that has this feature. Normally, the units labeled as “DI”, “CV” or “DS”, have this sonar feature built-in. Also, in order to benefit from the down view, it requires a specific type of transducer, that typically operates at 455 kHz, or has dual-frequency, of 455 / 800 kHz.

The down imaging sonar technology works basically the same as the traditional sonar, only the images are much sharper and clearer. The main advantage is that it allows you to distinguish much better between fish and structure. For example, if the sonar passes over a sunken tree, you will be able to determine if there are fish between its branches or not. In traditional sonar view, there’s a good chance you’ll only see the tree.

The down imaging sonar view normally scrolls on the screen from right to left. Your boat is placed in the upper right corner. In most cases, the water surface will appear as a white, irregular line, irregularity given by the turbulence of the motor of your boat.

The transducer emits sonic pulses into the water which return back to it, providing a specific amount of data about the underwater environment. Each sonar return will materialize on the screen as a thin, vertical plane. As the transducer is dragged through the water, these narrow planes will stack, providing you with a final image of the water column, bottom, fish and structure behind the boat.

To put it differently, you can imagine a big water tank behind and below your boat, and yourself on its right side, looking into it. The thing is, the image will appear in 2D, and will be a bit difficult to assess where exactly the fish caught by the beam are, in relation to the boat. You won’t be able to tell whether they’re to the right or to the left. But you’ll know they’re somewhere inside the water column below and behind the boat.

What Can It Do For You

DownScan Imaging is a kicker when fishing in waters with a lot of structure. That’s because it offers a superior quality imaging to the traditional sonar, and it’s much easier to spot the fish hiding among structure. On classic sonar, the returns for fish close to structure may mix

together, and you won’t see them.

If the sonar signal passes over fish, they will appear on the screen as bright white dots. Bait balls will appear as cloud shapes. Weeds show up as lines, reaching up from the bottom, and you will actually assess how far up from the bottom they extend. This basically goes for every other piece of structure the sonar catches. Evidently, you will also see how up in the water column the fish are located.

This way, you will know exactly at which depth to maintain your lure, or how up from the bottom your baits must be placed.

Other Aspects Important to Know About Down Imaging

When choosing a fish finder with DownScan, many anglers overlook the fact that this technology is quite limited. On average, most fish finders with down scanning sonar offer a depth capability of 300 ft. (91 m). The transducer must be mounted correctly and the boat run at the required speed, in order for it to function at normal parameters.

Also, in case you will buy a unit with a smaller screen, which has a split-screen function, you should be aware that when observed in split-screen, the down view will appear much smaller, and so will be the returns. That shouldn’t be a problem though, because you can always view your sonar in full screen, in single view mode.

Okay, I think I’ve covered most of the key-points regarding Down Imaging sonar technology. By now you should have a pretty good idea what it’s about and what it can do for you. So, here are a few aspects that you should know about the fish finders with this type of sonar.

Things To Consider Before Purchase

The type of fishing you’re going to use your unit for

As I mentioned above, Down Imaging is a sonar technology designed for depths up to 300 ft. (91 m). It will be completely useless to you in a deep sea fishing session. For this type of fishing it’s best to use a CHIRP sonar, or at least a fish finder with a transducer that operates at 50 kHz frequency.

Since the sonar beam emitted by the transducer covers only the water column below your boat, you won’t benefit from an extreme coverage. I mean, depending on unit and transducer, the beam can extend for up to 60°. That’s still a good coverage, but it can’t be compared with the huge portion of water covered by Side Imaging. So, keep in mind that if you will get a unit that only has DownScan and not SideScan, you will have to sail over a wider area multiple times, in order to see every good fishing spot.

Type of boat

Depending on the boat you have, you may require a different type of transducer. For example, a fiberglass boat may require a through-hull transducer, while an aluminum boar with a flat transom, would require a transom-type transducer.

In case you will be using a kayak or a rental boat, a smaller, or even a portable unit may be more indicated.

Transducer

This is a very important aspect to know about a certain fish finder before you purchase it. Even though various models are advertised as DI fish finders, that may only stand for the head unit of the model. In other words, the unit is capable of DI. But the box may not include the Down Scan specific transducer, which you will have to pay extra for. Therefore, make sure you purchase a unit that has the Down Imaging sonar built-in the unit, and the box also includes the DI transducer.

Other Features of the Unit

Needless to say, the more features or options a device such as this has, the higher the price. Most units that come with DownScan and SideScan, also include quite a wide array of navigational features. You may not need, nor want any of those. Therefore, in this case, it might be a good idea to opt for a unit that focuses exclusively on fish finding capabilities, without being a chartplotter as well.

Pricing

Maybe the best indicator for the price range of a fish finder is the diagonal of the screen. In general, a unit with a screen over 7″ in diagonal, isn’t exactly cheap. In general, the bigger the head unit, the higher the number of features and options the unit has. However, not all widescreen units may include all the features they’re advertised for. They may support a wide range of technologies, but most of them have to be purchased separately. Example: the Humminbird ION 12.

Touchscreen technology also reflects a higher price. There’s a good chance you will find a fish finder with the same sonar and chartplotting capabilities, but with regular navigation (through buttons), for a better price.

Most (if not all) fish finders that come with Side Imaging, also include Down Imaging. But there are units that support only Down Imaging, such as the HELIX 5 DI GPS from Humminbird, for example. These units are normally cheaper than the similar ones with SI as well. Of course, the more features, the higher the price.

When it comes to pricing, there are Down Imaging fish finders beginning at $150. And for a price under $1,000 you can get quite an exceptional fishfinder and chartplotter.

In the following part of this post, I’m going to point out for you, some of the best DI fish finders by price range. And when it comes to Down Imaging sonar, without Side Imaging, it appears that Humminbird is holding most of the cards in terms of fish finders.

A Few Recommendations…

Humminbird PiranhaMax 4 DI

The PiranhaMax 4 DI is one of the fish finders released by Humminbird in 2016 but it is still available in 2021. It’s one of the most affordable Down Imaging fish finders at the moment. However, it does not have any navigation functions (no GPS, no maps). For reference, this is the Humminbird part number 410160-1.

The unit has two types of sonar. These are DualBeam standard and Down Imaging. It does not have CHIRP technology. It supports two frequencies, these being 200 kHz and 455 kHz.

The transducer included with the PiranhaMax 4 DI fish finder, is the XNT 9 DI T. This is a plastic transducer with a transom mount. It has 20 ft. (6 m) of cable, and integrates a temperature sensor. It supports both sonar technologies provided by the unit. For the Dual Beam sonar, it can use two conical beams, one for 200 kHz with a coverage of 28°, the other for 455 kHz with a coverage of 16°. For Down Imaging, it can use only the 455 kHz channel. The beam is oval and thin but offers a coverage of 75°. The maximum depth capabilities of this fish finder system are 600 ft. (183 m) for the DualBeam sonar, and 320 ft. (97.5 m) for the Down Imaging sonar.

The unit has a 4.3″ diagonal display with a pixel resolution of 480V x 272H and LED backlight. It is also IPX7 waterproof. Its interface is very easy to use and highly intuitive. It does not have touchscreen technology. It also does not have any networking features. It comes with the standard tilt-swivel mount.

Garmin Striker Vivid 5cv

The Striker Vivid 5cv is one of the fish finders released by Garmin at the end of 2020. As opposed to the older Striker Plus 5cv, this one offers several (7) extra color modes for its down scanning sonar. By changing the color palette, sometimes you can benefit from a better view of the underwater environment.

The fish finder unit has two sonar technologies. These are standard CHIRP and ClearVü. It does not support Panoptix sonar. It is capable of multiple frequencies, including 50/77/200 kHz for the standard CHIRP sonar, and 260/455/800 kHz for the ClearVü down scanning sonar.

The unit includes the classic GT20-TM transducer which integrates a temperature sensor. It has 20 ft. of cable with a 4-pin connector and comes with a transom mount. This transducer is dual-beam capable. For the standard CHIRP sonar, it uses two conical beams of 15° @ 200 kHz, and 45° @ 77 kHz. The maximum depth capability for the 2D CHIRP sonar element of this transducer is 1,900 ft. (579 m). For ClearVü, it uses thin oval beams with a coverage of 2.5° x 53° @ 455 kHz, and respectively 1.6° x 29° @ 800 kHz. The maximum depth capability of the ClearVü sonar (in freshwater and perfect conditions) is 750 ft. (228 m).

The Garmin Striker Vivid 5cv is not a chartplotter but does have basic navigation features. It is equipped with a GPS plotter that offers the possibility to see your position and coordinates, mark waypoints, create routes, and record tracks. It does not support charts but does have the Quickdraw Contours feature. With this application, you can create your own fishing maps with the most up-to-date depth contours.

The unit has a 5-inch diagonal display with a pixel resolution of 800H x 480V. It is not networkable. It does not have NMEA or Ethernet ports and does not have wireless connectivity. It comes with a standard tilt-swivel mount, and a transom mount for the transducer.

Humminbird HELIX 5 CHIRP DI GPS G2 Navionics+

Although the HELIX 5 CHIRP DI GPS G2 fish finder is pretty old, one of the models released by Humminbird in 2017, it is still available in 2021. It’s a chartplotter as well, and as the title suggests, it comes with the Navionics+ charts.

The unit is equipped with two sonar technologies, Down Imaging and CHIRP DualBeam Plus sonar. It supports multiple frequencies including 50/83/200/455/800 kHz. It comes with the XNT 9 DI T which uses two conical beams for DualBeam Plus. Their coverage is 25° @ 200 kHz, and 16° @ 455 kHz. The maximum depth capability of the DualBeam Plus CHIRP sonar is 600 ft. (183 m).

Conversely, for Down Imaging the transducer uses two oval beams that offer considerably more coverage. The 455 kHz beam offers a coverage of 75°, while the 800 kHz beam has an angle of 45°. The maximum depth range of the Down Imaging sonar provided by this Humminbird fish finder with the included XNT 9 DI T transducer is 350 ft (106 m).

The unit has built-in GPS. Therefore, you can always view your position, mark waypoints, create routes, and record tracks. It is pre-loaded with the Humminbird Basemaps which cover more than 10,000 U.S. lakes and also provide coastal water coverage. Plus, the unit comes with a Navionics+ microSD card. The Navionics+ charts offer considerably more detail than the Humminbird maps, are 1 ft HD bathymetry charts that offer coverage for more than 21,000 lakes and water bodies in North America, Nautical Chart guides, Sonar Chart HD bathymetry mapping, and free Community Edits for a full year. Plus, the unit has the AutoChart Live feature which gives you the possibility to create your own custom maps.

The unit features a 5-inch LCD color display with LED backlight and a pixel resolution of 800H x 480V. It supports NMEA 0183, but not NMEA 2000. It also doesn’t have an Ethernet port, WiFi, or Bluetooth Connectivity. However, it does have a microSD card slot which you can load with the provided Navionics+ card, or with a different card for software updates, or sonar recordings or data backup.

Lowrance HOOK Reveal 5 SplitShot Inland

The HOOK Reveal series includes several fish finders released by Lowrance in 2020. The HOOK Reveal 5 SplitShot is similar to the older HOOK2-5 SplitShot, but comes with two important new features. One is FishReveal, the other is Genesis Live mapping.

The unit comes with the SplitShot transducer which has a transom mount and an internal temperature sensor. For the 2D CHIRP sonar, this transducer can only use the 200 kHz channel with High-Wide conical beam featuring a coverage of 40° and a depth range of 500 ft. (153 m). For DownScan, the SplitShot transducer can use both 455 kHz and 800 kHz frequencies. The beams coverage is 55° / 3° @ 455 kHz, and 35° / 1.6° @ 800 kHz. Their maximum depth range is 300 ft. (91 m) @ 455 kHz, and 150 ft. (46 m) @ 800 kHz.

The FishReveal gives you the possibility to bring the fish arches from the CHIRP sonar into the DownScan view and also opens specific FishReveal options. However, the older Overlay DownScan application is also available.

The unit has built-in GPS, can save up to 3,000 waypoints in its memory, and can provide enhanced data via GLONASS, WAAS, EGNOS, and MSAS. It is pre-loaded with the basic U.S. Inland Basemap from C-MAP. These charts cover more than 4,000 U.S. lakes with 1-foot contours. However, the unit supports premium charts from C-MAP and Navionics, including Navionics Gold, Navionics+, Navionics Platinum+, C-MAP Insight Pro, and C-MAP Lake Insight.

The Genesis Live feature is similar to the Quickdraw Contours application from Garmin, or the AutoChart Live application from Humminbird. It’s a bathymetric map creation feature that uses the 2D sonar and GPS data to reveal and record the depth contours of your lake. Thus, you can create your own charts with it.

The unit is not networkable. It does not have Ethernet or wireless connectivity. It features a 5-inch color display with a pixel resolution of 800H x 480V. It has a microSD card slot for chart upgrades and other data transfers. And finally, the unit comes with the standard tilt bracket mount.

Garmin ECHOMAP UHD 63cv

The ECHOMAP UHD series was released by Garmin at the end of 2019. Unlike the Striker Vivid models, these support charts and have superior navigation features. The ECHOMAP UHD 63cv 010-02330-01 is one of the smallest units from this series. Evidently, it’s also one of the most affordable and the one with the most 5-star reviews.

The Garmin ECHOMAP UHD 63cv offers two sonar technologies. These are standard CHIRP sonar and ClearVü. As the unit’s name suggests, the ClearVü sonar has the UHD mode for improved imaging.

The unit comes with the GT24UHD-TM transducer which has a transom mount, 20 ft. (6 m) of cable with an 8-pin connector, and an internal temperature sensor. This transducer uses two beams, one for standard CHIRP and one for the UHD ClearVü. For the 2D CHIRP sonar, it uses the 150-240 kHz frequency range; the beam is conical and has a variable coverage of 24°-16° with a depth range of 800 ft. (244 m). The UHD ClearVü, it uses the 760-880 kHz range. The ClearVü beam is oval with a coverage of 0.94° x 60° and a depth capability of 200 ft. (61 m).

In terms of navigation features, the ECHOMAP UHD 63cv is equipped with an internal 5 Hz GPS receiver. It is pre-loaded with the LakeVü g3 charts. These charts cover more than 17,000 U.S. inland bodies of water (rivers, lakes, reservoirs), in high-detail and with up to 1-foot depth contours. These charts come with other useful features such as Depth Range Shading and Auto Guidance. Plus, the unit is compatible with the BlueChart g3 maps, as well as the superior version of the inland maps, the LakeVü g3 Ultra.

Along with the LakeVü g3 charts, the unit also has the Quickdraw Contours feature. This application uses the 2D sonar information and the GPS data to reveal and record the depth contours of the body of water that you are scanning. With this application, you can map your own favorite lake, and create your own custom fishing maps.

The unit is equipped with a 6.2″ WVGA display featuring a pixel resolution of 800H x 480V. It has NMEA 0183 ports and is NMEA 2000 compatible. Therefore, you can hook it up to an already existent NMEA network on your boat so it can communicate with other boating instruments such as AIS units or DSC-capable VHF radio units. It also has wireless connectivity and is compatible with the ActiveCaptain app. And finally, the unit comes with the quick-release mount.

Raymarine Dragonfly 7 Pro

Although the Dragonfly 7 Pro is one of the units released by Raymarine in 2016, it is still available in 2021. This unit comes in various bundles with different transducers and maps. So, in this short post, we’re going to address the model number E70320, the one that comes with basic charts and the CPT-60 transducer.

In terms of sonar, the Dragonfly 7 Pro has two technologies. These are standard CHIRP and CHIRP DownVision. The CHIRP frequency ranges are 170-230 kHz for the 2D traditional sonar and 320-380 kHz for DownVision. Needless to say, you can work with both sonar modes in split-screen. Also, it’s important to mention that the unit does not support SideVision or RealVision 3D.

The included CPT-60 transducer features a transom mount, 33 ft. (10 m) of cable, and an internal temperature probe. It uses one beam for each type of sonar. For the standard CHIRP sonar, the beam is conical, with a coverage of 25° and a maximum depth range of 900 ft. (275 m). For DownVision, the beam is thin and oval-shaped, with a coverage of 60°/1.4° and a maximum depth range of 600 ft. (183 m).

For navigation, the unit only has a 72-channel built-in GPS receiver. It also has a GPS speed function and can work with WAAS, EGNOS, and MSAS for position enhancement. The unit can hold up to 3,000 waypoints in its memory, and up to 15 tracks, with 10,000 points each.

The unit’s charts are the most basic. They do not offer too much nautic information. However, there is a microSD card port that allows you to upgrade its chart base. It supports Navionics Gold & HotMaps, Navionics+, LightHouse Vector, and Raster charts, and chart from C-MAP.

The unit has a 7-inch WVGA color display, with a pixel resolution of 800H x 480V. It is IPX7 waterproof which means it can withstand incidental water exposure. It doesn’t have touchscreen technology, only the trackpad +/- zoom buttons, a back command button, and the power button. The unit does not have Ethernet or NMEA connectivity but does have internal WiFi. Therefore, you can sync it with your smartphone in order to control it remotely.

Lowrance Hook Reveal 7 SplitShot US Inland

The Hook Reveal 7 SplitShot offers a similar range of features the Hook Reveal 5 SplitShot has a wider 7-inch display. It’s also a chartplotter, offering a fairly decent range of navigation features. For reference, this is the Lowrance fish finder part number 000-15512-001.

As its name suggests, the unit has SplitShot sonar (standard CHIRP and DownScan). It supports multiple frequencies, including 50/83/200 kHz for the traditional CHIRP sonar, and 455/800 kHz for DownScan. It’s also important to mention that it does not support SideScan, ForwardScan, or ActiveTarget sonar.

The unit includes the SplitShot transducer which comes with a transom mount, 20 ft. (6 m) of cable, and has an internal temperature sensor. For the standard CHIRP sonar is only uses a conical beam at 200 kHz, with a coverage of 40° and a depth range of 500 ft. (153 m). For DownScan, it supports both 455 kHz and 800 kHz. The beams are oval, with coverage of 35° and 55°. The maximum depth range of the DownScan sonar that can be achieved with this transducer is 300 ft. (91 m).

The unit has built-in GPS and is pre-loaded with the C-MAP US Inland Basemap. These charts cover more than 4,000 U.S. lakes with 1-foot contours. However, the unit supports premium charts from C-MAP and Navionics, including Navionics Gold, Navionics+, Navionics Platinum+, C-MAP Insight Pro, and C-MAP Lake Insight. The GenesisLive feature for bathymetric mapping is also available with this Lowrance unit.

The control unit features a 7-inch color display with a pixel resolution of 800H x 480V. It does not have touchscreen technology, just the side keypad. Just like the other Hook Reveal units, it does not have networking features or wireless connectivity. However, it does have a microSD card slot which you can load with a data card or a Navionics charts card. The unit comes with the standard tilt mount and unit corner clips, but a unit cover is not included.

Simrad GO5 XSE HDI Basemap

The Simrad GO5 XSE is not exactly one of the newest fish finders; it was released in 2015. But just like the HELIX 5 CHIRP DI GPS G2, is one of the units that still continues to gather 5-star reviews from users.

This particular Simrad unit is actually capable of SideScan sonar too, along with DownScan and standard CHIRP sonar. However, in this post, we’re going to address the 000-12452-001 model, the one that comes with the HDI transducer.

The unit itself supports multiple frequencies, including 50/83/200 kHz for standard CHIRP and 455/800 kHz for DownScan. The included HDI transducer uses conical beams for the standard CHIRP sonar, with a coverage of approx. 52° @ 83 kHz and 22° @ 200 kHz. For DownScan, the beams are thin and oval; their coverage is approx. 56° / 2.8° @ 455 kHz, and 32° / 1.6° @ 800 kHz. The maximum depth range with the included transducer is 1,000 ft. (305 m) for the CHIRP sonar, and 350 ft. (106 m) for DownScan. As we’ve mentioned above, you can also pair this unit with a TotalScan transducer in order to use SideScan. However, only the newer models support Active Imaging.

The Simrad GO5 XSE 000-12452-001 has a 32-channel, 10 Hz internal GPS antenna which means it can offer position updates 10 times per second. It can save up to 6,000 waypoints, 500 routes, and 50 tracks in its memory. It has a GPS speed function and can use WAAS, MSAS, and EGNOS for position augmentation.

The unit is pre-loaded with the standard basemap. This chart base doesn’t offer super detail but it’s still considerably better than just a basic GPS plotter. It has a microSD card slot, though, and is compatible with charts from Navionics, C-MAP, Insight Genesis, and NV Digital Charts.

Finally, this Simard fish finder features a 5-inch display with a pixel resolution of 800H x 480V. It has a touchscreen interface that is very easy to work with and to customize. It does not have Ethernet but does have a NMEA 2000 port. It also has WiFi connectivity so you can sync it with your smartphone via the Navico GoFree app for software updates, chart downloads, and more.

All these Down Imaging fish finders currently stand at an almost completely clean 5-star rating on most retailer websites. Our selection here covers most budgets, starting with units under $200. Also, most of these fish finders have at least a minimum of navigation features, so they can be versatile navigation tools, not just devices for finding fish and measuring water depth.