Castable Fish Finders

The Castable Fish Finder Buying Guide covers several new products on the market today bringing more advanced technology and software to fishing.  Specifically, Garmin, Lowrance, and Deeper have shrunk fish finding technology usually found on boats and squeezed it into lure-sized devices that can be cast from shore using a rod, reel, and fishing line.  Do these castable fish finding devices work?  Are they worth the money?  Do they help anglers catch more fish?  The Baitstick team wanted to know the answers to these questions so we purchased a few of these devices ourselves at retail price and put them through testing on a Virginia bass lake near Charlottesville to find out.


Did Your Grandfather Need A Fishfinder While Casting From Shore?

Before opening any of the retail boxes from Garmin, Lowrance, and Deeper we had questions in our mind about whether castable fish finding sonar devices were even a good idea at all.  Traditionalists and fishing purists may question whether using fishing finding technology, especially from shore, is good for the sport of fishing to begin with.  Your grandfather probably didn’t need it so why should it be needed today?  Well, we now live in the 21st century and it’s hard to go five minutes without picking up a mobile phone or getting behind the wheel of a car without using locating technology.  So it’s not hard to see how sonar, radar, and GPS technology are now standard in fishing, even when just casting from the bank of a river or shore of a pond or lake.

What’s The Best Use Of $90 – $100 In Fishing?

Anglers fishing from boats have benefitted for years from the power and performance in the mounted fish finding devices designed for watercraft.  So companies such as Garmin, Lowrance, and Deeper have looked to anglers on shore as a new target for similar technology and benefit in fishing.  The castable fishing finding devices tested by Baitstick from Garmin, Lowrance, and Deeper range in retail price from $90-$100.

But do anglers from shore really need such devices when most anglers are often fishing frequently in the same locations and fishing spots? In this case, the price and benefit of even the best castable fish finding sonar device in the world may be limited if an angler simply does a few low tech steps to understand the area around them and what lies beneath the water.

After all, experienced anglers know that a lot can be determined about the terrain beneath the water and around the shore of a fishing spot by simply casting a large, hookless crankbait, weighted worm, or any lure that sinks and letting it drop to the bottom of the pond, lake, or river.  Slowly retrieving the weighted lure and feeling the change in line tension and direction of the line can provide a lot of information to the angler about water flow, bottom terrain, and presence of obstacles, structure, and vegetation in the water column.  Even if a lure is lost while going with the old school approach it can cost a lot less money than the $90-$100 spent on a castable fish finding sonar device.  But if money is no object or having the latest and greatest fishing product is most important then a castable fish finding sonar device may be something to consider.

How Do Fish Finders Work?

The hard plastic castable fish finders from Garmin, Lowrance, and Deeper are all designed to be easily attached to a standard fishing line (ideally 20lb test weight or higher).  The devices are also designed to be waterproof and are generally dimensionally similar in size and shape, all less than 4”L x 4”H x 4”W.  Once cast from shore, the devices read the water below the surface and perform similar to a more expensive transducer found on a boat or kayak.

On boats or kayaks, anglers get a view of the water below a boat or kayak from a transducer device mounted to the side of or inside the hull of the watercraft.  Transducers send and receive back a sonar signal to the bottom of the river or lake below the boat or kayak.  When the sonar signal bounces back to the transducer, the data from the signal is then fed to a separate monitoring device and screen in the vessel that the angler can use to view and understand what lies below the surface of the water.

In sending and receiving back a signal to the bottom of the lake or river, traditional transducers emit a sonar beam in the shape of a cone.  Anything inside this sonar signal cone can be picked up by the transducer.  Newer and more advanced devices on boats read the bottom of a river or lake by sending not one but two narrow scanning beams, similar to the shape of the beam in a copying machine. These twin beams typically provide better coverage than a single beam device and offer a clearer, picture-like image of what is beneath the boat.

For the angler on shore and without a boat or kayak, the castable fish finder devices act as a transducer.  By casting the fishing finding device on a line from a rod and reel, the angler can position the fish finder on the surface of the water and above the area the angler intends to target.

What’s Inside A Castable Fish Finder?

The castable fish finder devices Baitstick tested from Garmin, Lowrance, and Deeper all have single beam sonar capability.  Once cast in the water the devices send and receive a small sonar signal from the lure-sized plastic device.  The castable fish finders are paired and connected wirelessly to an angler’s mobile phone and can send data to an app on the phone.  The Garmin device tested used bluetooth to connect the castable device to the mobile phone app used during testing.  The Lowrance and Deeper devices used WiFi connections between the devices and the app running on the phone used for testing.  Similar to fish finders on a boat, the angler’s phone from shore through the different vendor apps becomes a monitoring device and screen that the angler can use to view what lies below the surface of the water.

The technology and design of castable fish finding devices is a good idea in concept.  But anglers not used to fish finding technology may need practice understanding what the devices can and cannot show well below the surface of the water.  Fish finders for example show what is happening at an exact moment.  So seeing a fish on a phone screen does not mean that the fish will still be there or actually caught when actually fishing, especially if the same rod and reel is being used to cast and retrieve the sonar device and then to cast and retrieve a separate bait intended to catch fish.  By the time a switch in gear is made, the fish may or may not be in the area as seen on the phone app.  Even if a separate rod and reel is used with bait tied on and ready to cast, the castable fish finding devices when working correctly will indicate the general area where fish may be present.

Garmin – Striker CastLowrance – FishHunter 3DDeeper – START
Price (MSRP)$99 ($149 w/GPS)$99$89
Item Dimensions (L”xW”xH”)3 x 2.97 x 2.281.87 x 3.23 x 3.234.33 x 3.15 x 4.33
Weight (Grams)7518080
Power SourceLithium-ion rechargeable batteryRechargeable batteryLithium Polymer rechargeable battery
Battery Charge Life10 hr10 hr6 hr
Estimated Range200 ft (65 m)200 ft (65 m)165 ft (50 m)
Sonar Frequency260/455 kHz381/475/695 kHz120 kHz
Max Sonar Cone63 degrees70 degrees40 degrees
Max Sonar Depth150 ft (46 m)160 ft (55 m)165 ft (50 m)
Operating Temperatures-4°F to 140°F-22°F to 95°F32°F to 104°F

How Do The Devices Perform?

The out of the box experiences for the three items tested were all fairly similar.  Each manufacturer provides simple guides to use in setting up the devices, including initial battery charging, software setup on mobile devices, and connecting the castable units to the respective apps on mobile devices.

During field testing, there was no significant difference in the ease of or ability to cast the different devices from shore.  The devices may need some adjustment for the location where an angler is fishing.  Castable fish finding devices can be affected by local weather and water conditions.  Different devices tested by Baitstick allowed for changes to be made to the devices to make them more accurate.  For example, the castable fish finder from Garmin allows for adjustment of the single beam frequency measured in kilohertz (kHz), enabling an angler to widen or narrow the width of the single sonar beam from the device.

In the Garmin, the 455 kHz setting gives a narrower beam width and is good for rough water conditions.  Viewing bottom definition and changes in water temperature below the surface can be better when using a higher frequency.  The Garmin’s lower setting (260 kHz ) uses a wider beam width, which covers a larger area and can help to see more fish or targets.  However, a wider beam can also capture more surface noise or false readings.  But a wider beam width can help capture more fish targets in a single view, making it useful for initially locating fish. Wider beam widths also perform better in deep water, because the lower frequency has better deep water coverage. Wide beams can also be used to search for structures such as rocks and logs below the surface and underwater structures.

The Lowrance castable unit comes with a similar ability to adjust frequencies and offers a maximum sonar beam cone of 70 degrees.  The Deeper START unit has a single frequency setting of 120 kHz with a fixed beam cone of 40 degrees.

The biggest differences between the three castable fish finder units tested came with performance and usability.  The performance of the units is significantly affected by the strength of the connectivity between the app on the angler’s phone and the castable units themselves.  If the castable units move out of range of the angler’s location with the phone then the connection between phone app and castable device will be broken or weak and there will be limited or no signal or image to monitor on the phone.  And even when the castable units are within range of the angler’s mobile phone running the different apps, there is no guarantee that the signal or flow of data will always be smooth or consistent if there is issue with the Bluetooth or Wifi signal.  In field testing, the Garmin Striker Cast suffered from poor image quality and display of the sonar readings even when within the manufacturer recommended range of 200ft was maintained between the mobile phone and the castable device in the water.   The Lowrance and Deeper products performed better with connectivity, possibly due to their use of WiFi connectivity as opposed to the Garmin unit’s dependency on Bluetooth connectivity.

User Experience Difference

In terms of usability, all of the products have adequate displays of location mapping and representation of the water column below the surface of the water as captured in the data collected by the castable units.  For users of boat or kayak fish finder technology, the data display and graphics of the castable units may seem crude, clunky, and too basic.  And for those new to fish finder technology overall, it may take some time getting used to exactly what is being displayed on a small phone screen.  Realistically, there are limits to the levels of detail that can be shown on a small mobile phone-based app display.  Still, in looking at the usability across all three devices, the Lowrance display and usability ranks last in comparison in terms of the quality of graphics and format of the fish finder display.

The graphics and visual representation of the terrain in the Lowrance phone app is very basic and the oversized representations of fish make the overall product limited to identifying the simple presence of what might be a fish with little additional clear information about the terrain and specific location of the fish.  In addition, Lowrance has put into the phone app a distracting amount of detail about Lowrance’s Fishhunter app that ties the user of the castable unit into Lowrance’s own social network of app users sharing information about log catches, waypoints, and live streaming of catches.  The Fishhunter feature on the Lowrance app left the impression that the company was caught between trying to get more anglers onto its social network as opposed to really helping anglers find more fish with the company’s best technology and effort in a castable fish finder device.

The Garmin performed slightly better in terms of usability.  The graphics on the app and the display of the sonar data from the castable Garmin device was clearer and more detailed.  Still, for anglers new to using fish finders it may require practice and time to better understand and read the display to recognize the difference between bottom structure and detail, including what is grass versus rocks versus fish resting on the bottom of a lake or river.  Even experienced anglers and users of fish finding technology may need time with the Garmin to reliably identify fish.  Unless the Garmin device is cast into deep water where fish can easily and clearly stand out in the water column, anglers may find the device early on better for simply understanding sub-surface terrain at the bottom of a river, pond or lake.  Regardless, with the Garmin the best sonar readings and data display on the app came when the castable device was moving slowly on retrieve at a steady pace and the castable device was not in deeper sections of the Virginia lake where testing was conducted.

Of the three units tested, the Deeper START unit performed best in terms of performance and usability.  The device from Deeper bested on price and value by having the clearest graphics and display of the sonar data and app reading of the water below the START unit on the water.  Navigation with the app was also the simplest and friendliest, making it easier to get basic data on sonar readings and accessing detail on fish and structure below the water surface.  The app was also the fastest and most responsive to changes in settings while the castable device was in operation and different readings were needed while fishing.  The Deeper START ability to record data and store data from a cast and retrieve was also a great feature.

The Winner and The Take-Away

While a castable fish finder device is relatively easy to set up and operate, it nonetheless takes some time to find and catch fish.  And if an angler fishes mostly in the same locations then the value of even the best fish finder may not replace the experience and knowledge from basic time on the water.  Fishing with a castable fish finder and a phone in hand can also be a distraction and the exact reason why many anglers even go fishing, to get away from the noise of daily life and distraction of phones.  More practically, casting a fish finder device, retrieving it, handling a phone near water, looking at and understanding a small screen app, and then actually fishing to catch a fish is a juggling act that itself will require practice while the fish wait or move on.

There are a lot of ways to spend $100 in fishing.  Typically, the best use of money is on a quality rod or reel or to load up on bait and tackle that is best for the river, pond, or lake where an angler is intending to fish.  $100 saved may even be one step closer to buying a boat or kayak.  But if an angler is set on essential gear and is still looking for more advantage in catching more fish from shore then a castable fish finding device may be the way to go.  In this case, the Deeper START is not only the cheapest of the three devices tested by Baitstick but also the best performer of the group from Baitstick field testing.

Baitstick supports efforts to build the next generation of anglers nationwide, including the Recreational Boating & Fishing Foundation (RBFF) and The Outdoor Foundation