Understanding kayak fish finders for coastal saltwater fishing, plus general installation & maintenance guidelines.
Fishfinders continue to evolve at such a rapid pace, it’s nearly impossible to keep tabs on the industry’s latest offerings. Rather than chasing the newest introductions, look at fish finders from a broader perspective. Focus on the transducer and multifunction display (MFD) capabilities, and tailor that to your style of fishing.
If you’re fishing saltwater environments, then a transducer featuring both a low or medium broadband signal (50 kHz or 83 kHz) and and a high frequency broadband signal (200kHz), plus an sd card slot for a detailed mapping chip, gets the job done. Most of today’s transducers, when paired with a Compressed High Intensity Radar Pulse (CHIRP) compatible display, feature CHIRP capabilities that send a sweep of signals within a range centered around a single frequency. This is a lot to digest, but the takeaway is that the sonar sweep enhances clarity and separation of sonar targets.
(Right) Author Howie Strech with the end result of dropping a yo-yo iron on a school of yellows marked on his fishfinder.
CHIRP isn’t a necessity for coastal saltwater fishing, but it’s certainly a luxury. Most of the MFD’s that Lowrance has manufactured in recent years are capable of running CHIRP. CHIRP sonar is especially useful when separating bottom from fish like halibut, or identifying suspended schools of smaller fish that are moving less in and out of your sonar cone.
For bay or freshwater fishing, I prefer a unit that has Side/DownScan sonar at the very least. Even consider forward facing or scanning sonar for its ability to identify transitions in bottom density, structure, bait schools and fish in a real-time horizontal plane all around your vessel. We’ll cover more about the live and scanning sonars in a future article. For the purpose of this article, my focus will be on coastal saltwater environments.
Transducer Frequencies – The Basics
Is there a direct correlation between cone angle and frequency? Short answer: no! Long answer: Historically, as transducer frequency increased, cone angle decreased. However, since technology, transducer materials and design have evolved, this fact doesn’t hold true. Beam/cone angle is more dependent on the actual crystal (element) used, how the crystal is being activated, how the transducer is designed and what materials are used to manufacture the transducer. A perfect example is the new Lowrance Hook/Reveal SplitShot and TripleShot transducers, where 200kHz has a 40 degree cone – similar to what you’d get out of a 50 kHz transducer of the past, but generating a more detailed picture on your display.
Single Frequency: Single frequency transducers are capable of running one frequency of 2D broadband sonar at a time. Historically, the standard go-to was a 50 kHz transducer for fishing La Jolla for its wide cone and strong depth penetration. This allows you to motor around slowly, and look at a wide body of water, which is great for identifying cruising yellowtail in the water column, but otherwise doesn’t give you a very complete picture. Historically, running a single frequency transducer at 200kHz gave you more detail, but less coverage. Most kayak friendly units you’ll find today have progressed beyond single frequency capability and don’t adhere to historical rules regarding frequency and cone angle.
Hybrid Dual Imaging (HDI): Lowrance HDI transducers yield the option of using broadband sonar in its available frequencies, in combination with DownScan. When paired with a CHIRP enabled multifunction display, HDI transducers can also run CHIRP sonar. DownScan operates at super-high frequencies (either 455kHz or 800 kHz) and provides mind-blowing detail in water less than 200 ft but doesn’t have great penetrating power. These frequencies should be reserved for identifying detailed structure rather than fish (i.e. grass, hard bottom, reef, kelp, boulders, sunken trees/brush). Since DownScan uses a separate sonar element, you have the ability to overlay DownScan images on top of broadband images. I personally don’t like the clutter, but it’s all personal preference.
According to Jeremiah Clark, VP & GM of Fishing Systems at Navico Group, running 83 kHz is ideal for fishing coastal saltwater environments for gamefish like yellowtail, seabass and halibut because the beam/cone at that frequency is nearly as wide as 50kHz but has better detail. This means gamefish have a better chance of entering your sonar cone and also spend longer inside the cone when you mark them. This is what gives you those classic “worms” on the display when you meter a school of yellows or seabass. When it comes to HDI transducers, I prefer the 83/200 version for its generous beam angles and optimal frequencies.
Here’s some specs:
- HDI Med/High (83/200)
- 83/Mid = Approximately a 35 degree beam/cone
- 200/High = Approximately a 20 degree beam/cone
- HDI Low/High (50/200)
- 50/Low = Approximately a 40 – 50 degree beam/cone
- 200/High = Approximately a 12 degree beam/cone
CHIRP Sonar: CHIRP delivers higher resolution images than broadband sonar by continuously sweeping through a range of frequencies centered around the typical 50kHz, 83kHz or 200kHz. Historically, low CHIRP suggests a wider cone that performs best in deep water for its penetrating power, while high CHIRP suggests a narrower scope with less penetrating power. With that said, technologies have advanced, and modern day high CHIRP transducers offer wide angle versions that provide a “best of all worlds” solution. For super deep water, Low Chirp is still the best option for its penetrating power, however if you’ve got a 1Kw High CHIRP transducer it will perform surprisingly well in the deeper stuff too. The transducer on my center console power boat offers a 25 degree beam and 1Kw power. This wide cone angle and sweep of high frequencies is perfect for offshore situations, and performs equally as well in the coastal waters that I like to fish.
Side/DownScan: The Side/DownScan feature on transducers is available on entry level on up to premium level Lowrance units. Operating at 455kHz or 800kHz frequencies, scanning sonar provides high-resolution views to either side of the boat in the exact same way DownScan works. 800kHz provides the sharpest resolution at shallower depths, while 455kHz delivers the best overall image quality and depth penetration. In situations like shallow grass flats or banks, where vertical sonar isn’t effective, side imaging allows you to detect fish, bottom density and structure changes. SideImaging takes some practice to use, but can even be extremely helpful in detecting bait and conditions over the top of laid down kelp stringers (hint, hint – seabass!).
My Favorite Units: Value, Mid-Range and Premium
Lowrance Hook Reveal – I run a 7” Hook Reveal on my Hobie Outback for its screen size and features. The 7” screen is large enough to make differentiating returns easy without constantly using the zoom function. I pair a TripleShot transducer with the Reveal since I have a retractable Guardian mount integrated into my Outback. If I didn’t have the Guardian mount, I’d probably opt to run a SplitShot or HDI so I could mount the transducer inside a protected transducer cavity.
The TripleShot does what I need it to do in depths up to around 200’. The transducer allows me to select either 200kHz or High Chirp, plus Side/DownScan. My most commonly used frequency is 200kHz because it has a 40 degree cone angle, which is equivalent to the coverage of an 83 kHz HDI transducer, but with better detail.
Hook Reveal includes a built-in mapping card slot, is available for purchase with a choice of included detailed maps, and also allows you to choose a range of compatible transducers. All Lowrance units are designed to run well on auto settings, but learning to tweak your advanced settings can make a huge difference. The key to understanding the effect of different settings is time on the water. Take the opportunity to tweak custom settings a little bit when you’re marking a school of fish and see what it does for the on-screen image. Check the “Advanced Settings” section below for more info.
(Left) The Lowrance Elite-7 Ti displaying a tight school of yellowtail directly underneath a large bait ball of mackerel.
Lowrance Elite-7 Ti – I ran an Elite 7Ti on my Pro Angler 14 for years, and it met every single one of my needs for coastal saltwater, bays and lakes. I paired a TotalScan transducer with this display, and fished it primarily on 83kHz for coastal saltwater fishing up to 300’. The transducer supports 83kHz, 200kHz, medium and high CHIRP, and 455kHz/800kHz StructureScan. The TotalScan has a bit better range than the TripleShot, which is its main advantage, but it essentially performs the same functions. The biggest difference you get with the jump up to mid-range is touch screen and connectivity with certain accessories.
A new generation of this unit launched a few years ago and is now sold as Elite Ti2. Elite Ti2 utilizes the new generation of TotalScan, which is called ActiveImaging 3-in-1. The new units provide a bit better screen clarity, fish reveal and enhanced detail. Otherwise the basic functions are the same. I highly recommend either Elite Ti generation if you are looking for a do-it-all saltwater machine with a touch screen!
Lowrance HDS – I ran an HDS 7 on one of my kayaks for a while and loved it. HDS takes the Elite Ti offering to the next level with enhanced screen clarity, a stronger sonar signal, more accurate GPS, faster processor, multi-touch capabilities for “pinch” zooming like a tablet or smartphone. It also features dual micro sd card slots (one for general storage and one for mapping chips), and expanded connectivity options. Check the link for more detail. Unless you’ve got an unlimited budget, the Elite Ti series is more practical for kayaks – especially for coastal saltwater environments.
Once you graduate out of understanding your fish finder on its automatic settings, you can tailor your fishfinder’s display by adjusting advanced settings to suit your style of fishing. Though it’s not as pretty to look at, you shouldn’t let some interference on the screen bother you. In fact, you’ll find that you’ll see more and better returns with a bit of interference on the screen. Interference is a good thing!
A large bait ball marked and displayed on the fishfinder at 83 kHz.
Here’s an outline of what my advanced/optional settings look like on my Hook Reveal 7. These settings can be used as a good starting point for any Lowrance, B&G or Simrad unit:
- Sensitivity: Auto +2 or +3
- Ping Speed: Max
- Scroll Speed: Normal
- Noise Rejection: Low or Off
- Surface Clarity: Low or Off
- Colorline: 76%
- Split: No Split
- A-Scope: On (this tells me what’s directly under the kayak)
- Pallette: 1
- Fish ID: Off
- Overlay DownScan: Off
The high-end units have built-in high definition mapping for lakes and coastal saltwater in the US. If you don’t have a “premium” unit with integrated detailed mapping, I highly recommend a mapping chip. These maps come in the form of a micro sd card that plugs directly into the card slot on any of the above units I mentioned, and gives you instant access to hi-res bathymetry, shaded relief, depth shading, tides and currents, and full-featured vector charts.
Two mapping chips to consider:
- C-MAP® REVEAL™ – US West Coast and Baja California ($249.90)
- C-MAP® DISCOVER™ – North America ($124.90)
Mounting the Multifunction Display
Most fishing kayaks either have a gear track already integrated forward of the seat that makes a great place for mounting a fish finder with a max screen size of 9”, or a gear track can be added atop the gunnel. Some Hobie kayaks have a 12-sided H-Rail mounting rail that serves as a great place to mount a fish finder display as well.
My brand of preference for fish finder mounts is RAM® Mounts. The beauty of these mounts is the double ball mounting system used to achieve virtually infinite adjustability. Their Track Ball™ mounts are the easiest fish finder mounts to use, and they adapt directly to all standard gear tracks. I recommend a C-Size ball mount for all the 7” screens mentioned in this article. Anything smaller won’t feel very secure. Check out their website to search by fish finder make and model to make sure you end up with a compatible mount.
Mounting the Transducer
There are a variety of integrated fish finder mounts that are factory installed on modern kayaks. Be sure to consult your dealer, or the manufacturer to see what’s needed for mounting a specific transducer. YouTube is a great resource. I’ve personally done countless videos on mounting different transducers on the full offering of Hobie factory installed and aftermarket transducer mounts. Those videos can be found on Hobie’s YouTube channel. Mounting specific transducers on some models require aftermarket transducer mounts, but they aren’t very expensive. A great resource for obtaining aftermarket transducer mounts for your make and model is BerleyPro.
Batteries have come a long way from the days of heavy sealed lead acid batteries. Generally you’ll want to stick to a 12v lithium ion or Lithium Iron Phosphate battery that is rated 10Ah or more. Somewhere between 10Ah and 23Ah is the sweet spot for the ideal balance of longevity and weight. Lithium batteries shave tons of weight compared to SLA, they perform at full capacity until they die, and they accept many more charges than SLA batteries. Not to mention, their charges don’t deplete on the shelf. There’s two options I personally trust for powering a fish finder on my kayak, both of which will power any of the above units for more than a full day of fishing:
Many modern fishing kayaks, when bought new, come with standard transducer and power cable installation fittings. Some installs require special kits or aftermarket transducer mounts, and you can obtain those from your kayak dealer. Make sure you are using the right stuff and don’t cut corners. Use adhesive lined heat shrink butt connectors to waterproof any electrical connections, install fuses where required, and use a high quality dielectric grease to protect plugs, pins and gaskets.
After each trip, your MFD can be cleaned with a light misting of water and dried with a microfiber towel. Once the display is misted with water and completely dry, apply a StarBrite Screen Cleaner and Protectant. The next step is misting plugs, drying and applying CRC Dielectric Grease aerosol to plugs, pins and gaskets.