Humminbird 998c SI Fishfinder Reviews

Humminbird 998c SI Fishfinder Reviews

Are you looking for a fishfinder tool that helps you detect fishes with accuracy in deep and shallow waters, any time during the day? If yes, the Humminbird 998C SI Fishfinder is the right choice for you. This is a technologically advanced tool, which comes with unique but easy to use features. In this article, we will take you through some of the remarkable features of this tool along with a brief overview of how to use it with the help of the manual.

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Humminbird 998C SI Fishfinder Reviews – Updated 2020

Is the Humminbird 998c SI worth the hype that surrounds it? Does it really help newbie and professional anglers as it promises? You will know the answers to these questions once you understand the features, pros and cons of this product, which we are going to discuss in the following sections.

Overview of the Humminbird 998C SI

Humminbird is one of the trusted names in the field of manufacturing fishfinders in different configurations. The 800 and 900 series of fishfinders from this brand is quite popular among anglers across the globe. The 998c SI is one of the most sophisticated models from this brand as it comes with a series of high-definition configurations such as the following:

  • Ultra-wide screen with side imaging sonar technology
  • DualBeam
  • SwitchFire
  • Down Imaging
  • Chart Plotting &
  • GPS Receiver

Do these seem like jargons to you? Don’t worry; we have broken them down into simpler terms for you in the features section, so that it is easy for you to understand the same.

Humminbird 998C SI Features

Here are some of the attractive features of the Humminbird 998C SI that make it one of the best-sellers in this category.

Side Imaging Sonar

The HD quality of side imaging sonar is a feature that is available only in a couple of select models released by Humminbird, and the 998C SI is one of them. Thanks to this feature, you will get a clear view of the areas that prone to attract fishes, regardless of the area and topography of the water that you are sailing on. This technology helps you search around 240feet on each of your sides to catch fish.

Though the sonar frequency is set at 455KHz here, you can choose the frequency of 800KHz as well in this feature. You need to remember that at 800KHz, the final image may be extremely sharp, but the search area on both sides may not be 240 feet. It would be far lesser than that.

Down Imaging Sonar

When you want to view the sonar returns of the lower beam portion from the Side Imaging beams, you can choose the down imaging view. The output comes in the form of clear and crisp 2D images, which are very easy to understand.

You can choose two frequencies of operation when you select the down-imaging sonar feature – 455KHz or 800KHz. If you are looking for good depth of your image quality, you can choose 455KHz; however, if you are looking for extremely sharp images, you can choose 800KHz. The instruction manual gives you detailed instructions on how you have to choose these menus to get what you want.

SwitchFire Mode

The Humminbird 998C SI gives you full control on how you want to view the sonar returns the way you want. You can choose to see more or fewer fish arches by choosing between two modes – Max and Clear.  The Max mode helps you get a clear view of the fish arches and monitor jig tracking better than before. The Clear Mode, on the other hand, helps you to view clutter-free, fish-size accuracy details.

Wide Screen

This model comes with an 8” widescreen that gives you crystal clear images in 480V x 800H resolution. The CCFL backlight that is included along with this fishfinder,  ensures that there is no compromise on the final image quality even during the nights.

DualBeam Plus Sonar

This tool is equipped with a 200/83 kHz DualBeam Plus Sonar System, thanks to which you can get wide coverage, depending on the depth of the water. The narrow, central beam gives you a 20-degree coverage, while the second beam gives you an extended coverage of 60 degrees. Now, you can easily view fishes that are 1500 to 3000ft deep.

QuadraBeam Plus Sonar

This is the technology that offers you an extra-wide 90-degree coverage when you set out to catch fish any time during the day. Here, you will notice a couple of 35-degree, fan-shaped, sonar beams that help to spot fish, bait them and provide you enough balance on the left or right side of the boat even on very deep waters. 

Thanks to this technology, you can now find a large number of fish than before in real quick time. It will also guide you where you have to place the bait, as the screen indicates where the fishes are exactly. This way, you don’t have to place the bait and wait endlessly for the fish to arrive.


  • 100% flexibility in viewing the DualBeam Plus Sonar returns in the view that you want; you can either view both the beams together or you can view them side by side or separately as well
  • Comes with a 50KHz transducer, which you can use when you are going for extreme deep-water fishing (greater than 3000feet deep)
  • Comes with a mounting system, thanks to which this tool can be connected to the dash whenever you want to
  • Dual SD card slot gives you lots of storage space for keeping visuals and recordings safe
  • Inbuilt contour XD map ensures that the tool comes loaded with almost all the major and minor water bodies along the USA coastline
  • GPS comes with an external antenna to make this model as sophisticated as possible
  • With a power output of 1000W and multiple options of viewing sonar returns, this is considered as one of the best-buys by professional anglers as well
  • Comes with a Freeze Frame option, thanks to which you can freeze the SI view by pressing any arrow on the 4-way cursor control key; using this freeze option, you can move the cursor to understand more about the quality of the sonar returns such as its depth, navigation, zoom levels and more
  • Split Sonar View available to compare the returns from various views such as DualBeam, Down Imaging and so on
  • Chart/Side Imaging Combo available where you have the Side Imaging sonar returns on one side and the chart view displayed on the other to draw conclusions and make good decisions


  • Display screen doesn’t come with a protection guard; therefore, it gets dirty easily
  • Some users noticed that when they switched on the Humminbird 998C SI, the transducer doesn’t get connected automatically
  • GPS connectivity is not very stable, and the details are not very accurate at higher speeds

Humminbird 998C SI Fishfinder Manual

If you want to follow the detailed instruction manual of the Humminbird 998C SI, you should check out the file from the Humminbird website.

In this document, you will the instruction manual for all the sophisticated 900 and 900 series of fishfinders from Humminbird. Some features are common for most of these models. Therefore, the “how to use” instruction is applicable to all these models, for all those common features.

How to use the Humminbird 998C SI Fishfinder

This instruction manual is quite exhaustive and it can confuse you to go through all the 100 plus pages in it. The best way you can learn how to use this manual is by searching for your respective model number. In this case, we are looking for the model, Humminbird 998C SI. All we need to do is to search for that model in this user manual to get all the details that we require.

This manual will take you through some of the interesting features of the 998C SI and basic instructions such as the following:

  • High-Definition Side Imaging Sonar
  • DualBeam Plus Sonar
  • Down Imaging Display
  • What kind of views you can enjoy in this model
  • Express Menus available on this specific model for various features
  • How to use the Sonar Menu Tab
  • How to use the Navigation Menu Tab

Under each of these headings, there are exhaustive explanations on how the technologies work, the range that the features offer and so on. The manual is detailed enough for newbie anglers to understand and get the tool into working condition as quickly as possible.

Bottom Line

We have analyzed quite a few fishfinders with some advanced features. However, we can definitely say that the Humminbird 998C SI is one of the best when it comes to performance, value for money and accuracy.  Despite its sophisticated features, it is quite simple and user-friendly as well. Therefore, you can use it with ease and confidence, even if you are new to fishing. So what are you waiting for? Get yourself one right now and save a great deal of time and money.

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