A bold statement: every aspiring or serious carp angler should own a Deeper sonar unit.
For those who don’t know, Deeper products are sonar devices that can be cast from shore and pair with an app on your smartphone to display depth, bottom make-up, weeds, structure, and even individual fish. Deeper, who are based in Lithuania but distribute their products worldwide, pioneered the technology and have been improving the tech and materials used in the units for more than a decade.
It’s a simple concept. You attach the device to your line and cast out. As soon as the unit touches water it will begin to send information back to the app for display on your phone. You can bungee your phone horizontally to the handle of your rod for viewing, hold in your hand, or mount on a tripod. As you slowly reel the device towards you, a dynamic left to right display shows all the bottom contours and other useful information throughout the length of the retrieve.
If you line up your cast with a marker on the far bank and assess how far you cast it out, you now have the equivalent of an underwater map for this slice of water. If you find something promising - 30 feet out, there’s a distinct shelf from 12 ft down to 15 ft with light weed growth - you can stand in that swim at any subsequent point and be confident of putting your hookbait and free offerings in a high-potential spot.
If you sometimes use a kayak or other watercraft in your carp fishing for baiting-up or feature finding, there are attachments available so you can simply swim the Deeper alongside your boat rather than casting it out. Depending on which model you choose, Deeper’s come with a lot of other accessories and functionality, like lake mapping. It's a really indispensable and versatile bit of kit.
Illinois resident Chris Matthews, who has frequently graced the Angler’s Insider newsletter with blogs and catch photos, as well as two excellent chapters in volume four of The American Carper, is a Deeper enthusiast and ambassador. ACS reached out to him for a few more advanced tips on how to get the most from the product.
ACS: Tell us a little about your background and what attracted you to Deeper?
CM: I’m 39 years old and currently live in central Illinois. I moved to the US from Coventry, England twenty ago this year. I’ve been fishing pretty much since I’ve been able to walk as my dad always loved to fish. I’ve targeted carp exclusively since moving to the States and really going full blown at it since 2017. I’ve been using a Deeper for quite a few years and been part of the Deeper team since early 2023.
From a young age my dad always taught me the value of watercraft, trying to understand where the fish might be and why, paying close attention and letting the water tell you where they are.
I still put a lot of value in that aspect of fishing. Using a Deeper allows you to confirm your intuition and gives you eyes under the water to help tell the story of why they might be there and even more importantly, what might keep them returning to the same spot.
You can clear a lot of ground with a Deeper sonar and get an immense understanding of what is happening without having to cast and cast a marker rod. While marker rods are still valuable, I personally lean more heavily on the Deeper nowadays as it's so much more efficient.
ACS: What are the things you're hoping to see in a new area using your Deeper? What are the things that would make you move on?
CM: When fishing a new water, I’ll always throw my Deeper out to help me visualize what kind of water I am setting up in, sometimes that means walking around the bank at first and casting out to potential areas where I believe fish will be.
I’m primarily looking to understand the topography of the water and to find clear and hard spots so my rig can present well on the bottom, not necessarily indications of individual fish. Hard areas show up as vivid color lines on the bottom ranging from yellow to red to orange. I’m also really looking for clues as to why a carp may feed in a certain area: deeper, cooler water in the hot summer months, a marginal or midrange shelf, small humps and plateaus, small depressions in the lakebed, weedbeds, other structure that might offer the fish protection or comfort.
On the other hand, if the swim is just too snaggy or weedy based on readings from my unit, I’ll move on to a new area. While it’s nice hooking fish, if you’re ultimately going to lose the majority of them to hidden snags it’s not worth your time and money and more importantly, the fish’s safety.
ACS: Any tips or tricks for getting the most out of the system if you’re new to it?
CM: The first thing I suggest is to turn off the fish icons! As a beginner, you can get too caught up seeing fish icons while not truly understanding what you are looking at and misinterpreting the data.
My standard settings are raw mode, the daytime palette (icon looks like the sun), and turn off fish icons. If fish are in the swim, they’ll still register but as red arcs of various sizes hovering off bottom. Generally the thicker the red arc the bigger the fish.
Reel slowly. You never want to reel your Deeper in fast - slow and steady gives the unit a chance to work to its full capacity and you a chance to take notice of every nook and cranny between the unit and your spot on the bank.
I adjust the sensitivity of the display according to the water I’m fishing. For most places, keeping the sensitivity between 60 and 80 helps clear out the clutter and gives a clean display.
You can also adjust the beam width of the unit, meaning how wide of an area below the unit is being picked up. Don’t assume what’s displayed on the app is just what’s directly below the unit - it’s more like a cone spreading out, especially over deep water. I’ll typically start off with a wide beam to get a good understanding of what’s below me, then narrow the beam width to focus on areas I really want to fish.
I use my Deeper primarily with a spod rod, though they’re light enough that any carp rod could easily handle one. Unless you’re in a boat, make sure the Deeper is set to bank fishing and tie to the top or middle mount on the unit.
I’ve found holding my phone works well while reeling the unit back in, but you can also buy a custom strap from Deeper that very securely fixes your phone horizontally to your rod. The strap allows you to keep a steadying thumb on the phone as you cast and then you can just slowly reel in with your other hand as you look down at the display. The best approach though or the one to use if you’re really paranoid about dropping or dunking your phone, is to mount your phone on a separate tripod and set it as high as you can to keep the signal strong.
Deeper comes in three models: the Start, the PRO +, and the CHIRP 2, and range in price from $89 to $249.
The American Carp Society is the USA’s leading authority on catch and release trophy carp angling. It is a membership based organization, dedicated to furthering the sport by educating the public on stewardship and conservation of our natural resources. By becoming a member you are supporting our efforts in helping to promote this incredible species to other anglers in the USA.