Comments on: Down-Imaging Vs. Side-Imaging Finally Explained!

By: Brad Carruth

Brad Carruth — Sat, 01 Aug 2020 15:34:38 +0000

Side imaging units also have down imaging. So it’s not like you will have to go without di if you buy a si unit. You buy an di unit and you only get di. You buy an si unit, you get both si & di.

By: Louis kovacs

Louis kovacs — Wed, 15 Apr 2020 13:30:13 +0000

Hope you can help
I recently purchased a humminbird helix 5 chirp si gps. You mentioned shallow water for side imaging , deep water for down imaging. At what depth should I change it from one to the other? I fish in water up to 30 ft. deep.
When should I use the contour mode? Every video i see, no one seems to use it. Why is that?

Thanks so much! Lou

By: Andy

Andy — Wed, 25 Mar 2020 19:07:34 +0000

Hello,
I’m looking for the capability to map and understand structure and depth as well as fish finding on small often very shallow rivers. I need to be able to see structure and depth that is often not directly under the boat since I fish from from a drift boat and no techniques I know of actually fish anywhere close to under the boat although getting a good understanding of the bottom contour as I go over it is incredibly important. The article mentions side imaging only works well at slow speeds, can you tell me how slow it needs to be and does the water movement, the boats speed in relation to the bottom or both effect the accuracy? Durability, weather proof, smaller size screen, and GPS locating as well as charting is important, screen size being the lowest priority are important. Obviously putting a $2000 unit on a $6000 oar powered boat is not realistic so cost is a factor like it is for most of us but function is most important. Any recommendations?

By: Jon Sutton

Jon Sutton — Tue, 02 Apr 2019 13:10:08 +0000

In reply to Rick Tranquilli.

Hello Rick,

Unfortunately, neither down-imaging or side-imaging transducers are designed for navigating underwater hazards.

Of the two, side-imaging systems will work best, but those still only detect what’s to the sides of your boat. What you want is a forward-looking or 360-degree sonar.

These will be more expensive than normal fishfinders and you’ll need to go slow while using them. Really slow. 3 knots, not 30 knots.

You do have a few options.

The Simrad ForwardScan can give you a look at what’s directly in front of you. It’s not known to be very accurate, though it is the cheapest option.

The Lowrance SpotlightScan Transducer is a side-imaging sonar that mounts to your trolling motor. It connects to Lowrance’s HDS Gen2 display. Rotate your trolling motor to get 360-degree imaging.

Finally, there’s the Hummingbird 360, which is a side-imaging sonar that rotates on its own. I haven’t heard good results from people who’ve used them, though.

Of these, I would most recommend the SpotlightScan. Keep in mind that all of these will be slow and short-ranged, so they’re more of an augment to your navigational skills than a replacement.

Good luck on the water!

By: Rick Tranquilli

Rick Tranquilli — Fri, 01 Feb 2019 12:19:10 +0000

Hi Ben,
Your comprehensive analysis is very helpful!

Can you help me pin down the best sonar technology and manufacturer for my unique situation?
I’m buying a boat to use for cruising (not fishing, at least not Yet!) on a freshwater lake in North Carolinainthe during the summer, and then in coastal South Carolina salt water in fall/winter/spring.

The challenge, especially of the freshwater lake is avoiding submerged trees and rocks in shallow water near my house and the inlet to my Boathouse. I’ve got to navigate the hazards under and side to side. During the coastal cruising avoid shallow sand bars at low tide.

Is side-imaging or down imaging the best for me?….or a combo?….and whatever your recommend for the best unit. I’ll be ordering the boat and specifying the unitfordash mount.

Thanks so much for a helpful recommend!