Skip to main content

Side-Imaging Today: The Humminbird 987c SI

Side-Imaging Today: The Humminbird 987c SI

Last year, Humminbird introduced a new type of sonar. Their high-end units now add Side-Imaging (SI) sonar standard color sonar imagery and GPS map navigation features. At roughly $2,000, the Humminbird 987c SI is about the most expensive sonar and GPS unit available. I find the SI to be a better searching tool than standard units.

Buyers gain a new search capability that simplifies the process of finding cover and structure likely to hold fish. The SI allows an angler to make passes down a shoreline or around important structures and mark spots as waypoints. The angler can then return to fish each waypoint to see if the spots are productive. Users more rapidly learn new waters and gain knowledge about underwater features they already fish.

Fish returns are smaller and more difficult to identify in SI imagery compared to standard vertical sonars. Schools of small baitfish appear as murky clouds rather than dark blobs. Fish the size of crappies or yellow bass may appear as small white dots, and individual gamefish like bass aren't much different than the returns created by stumps on bottom; but this is a cover-location tool, and effective use always has a learning curve.


Although gamefish and baitfish show as separate returns in SI imagery close to the boat, fish echoes farther to the side are mixed in with returns from the bottom and are more difficult to see. The clue that an SI return is a fish rather than a bottom or cover echo is a matching fish shadow farther away. Side imaging can help an angler locate and relocate moving schools of predator fish in relatively open water, but this is a bonus feature, not a primary benefit.


Beds of underwater vegetation are visible as marbled or bumpy bottom, but the soft edges of many submerged weedbeds may be indefinite. The prime benefit of SI is in definition of hard elements. Rockpiles and the deep edges of riprap are clear. Bridge construction and cover near pilings are revealed. Laydowns and underwater brush seen as blobs on bottom with vertical sonars become distinct logs and trees with defined branches. The clarity of various images recorded with the SI can be seen on the Humminbird website (humminbird.com). The increased fishing capability created by such detail is much like having photographs of exposed cover in a reservoir or lake.

Continued - click on page link below.


While the unit has many positive features, anglers should also be aware of its limitations. The SI unit's transducer must be located externally on the stern of a boat. The system works best at speeds under 10 mph and on straight-line courses, as turns distort the imagery.

How the stern is shaped and outboard motor is mounted influence whether the unit can "see" well to either side. Nothing may be placed in the line of sight to the sides of the transducer, and external mounting exposes the transducer to possible damage. Yet, I fish mine in Lake Fork, a water known for its hard-to-navigate stump fields, without damage.

I'm a beginner with the SI system and learn to better identify echoes and use other features on every outing. If you're a non-techie like me, you may find the complexity of menus and some options non-intuitive, but learning the details is rewarding. Users need to buy a map chip and may want another chip to record images for review with a personal computer.


Beyond conventional "fish-finding" sonars, the SI is worth the price if a user wants an advanced search tool.

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Recommended Articles

See More Recommendations

Popular Videos

Channel Cats on Ice

Channel Cats on Ice

The In-Fisherman staff reveals some of the hottest action of the winter season, as they show how to ice 20-pound channel catfish.

Hobie MirageDrive 360 Kayak Propulsion: Amazing Control and Power

Hobie MirageDrive 360 Kayak Propulsion: Amazing Control and Power

The Hobie MirageDrive 360 pedal propulsion system is the pinnacle of kayak control with more efficient fin designs, glide technology and allows the boat to be moved in any direction.

Drop-Shotting For Smallies

Drop-Shotting For Smallies

The In-Fisherman crew head to Lake Erie to catch smallmouth bass.

Lake Superior Whitefish on Ice

Lake Superior Whitefish on Ice

Doug Stange joins Capt. Aron Kastern on Lake Superior near Ashland, Wisconsin where they go after whitefish on ice.

See More Popular Videos

Trending Articles

Catfish are simple creatures that can be caught using the best catfish rigs. Catching them is simply a matter of putting a good bait in the right in front of them. 8 Best Catfish Rigs - When, Where and How to Use Them Catfish

8 Best Catfish Rigs - When, Where and How to Use Them

In-Fisherman

Catfish are simple creatures that can be caught using the best catfish rigs. Catching them is...

To guide your carp quest, we've lined up the best carp baits that are easy-to-fish natural baits and commercial options.10 Best Carp Baits Available Today Carp

10 Best Carp Baits Available Today

Dan Johnson

To guide your carp quest, we've lined up the best carp baits that are easy-to-fish natural...

Fall presents opportunities for both numbers and trophy fish.Stellar Late-Season Destinations for Panfish Panfish

Stellar Late-Season Destinations for Panfish

Steve Ryan - October 25, 2020

Fall presents opportunities for both numbers and trophy fish.

See More Trending Articles

More Accessories

In-Fisherman's top selections for the 2020 Holiday Gift Guide2020 In-Fisherman Holiday Gift Guide Accessories

2020 In-Fisherman Holiday Gift Guide

In-Fisherman Staff - December 01, 2020

In-Fisherman's top selections for the 2020 Holiday Gift Guide

An inside look at the new Ice Hunter Sidestep 285 from FrabillFishing Gear: Frabill Ice Hunter SideStep 285 Accessories

Fishing Gear: Frabill Ice Hunter SideStep 285

Thomas Allen - November 13, 2020

An inside look at the new Ice Hunter Sidestep 285 from Frabill

The GPSMAP x3 series features slimline design borders with edge-to-edge glass displays.Garmin debuts GPSMAP x3 Chartplotter Series with Higher-Res Displays Accessories

Garmin debuts GPSMAP x3 Chartplotter Series with Higher-Res Displays

In-Fisherman Staff - November 10, 2020

The GPSMAP x3 series features slimline design borders with edge-to-edge glass displays.

STRIKER Cast is a versatile sonar device that anglers can take with them wherever they go.Turn Your Phone Into a Fishfinder with Garmin Accessories

Turn Your Phone Into a Fishfinder with Garmin

In-Fisherman Staff - November 03, 2020

STRIKER Cast is a versatile sonar device that anglers can take with them wherever they go.

See More Accessories

Magazine Cover

GET THE MAGAZINE Subscribe & Save

Digital Now Included!

SUBSCRIBE NOW

Give a Gift   |   Subscriber Services

PREVIEW THIS MONTH'S ISSUE Arrow

Buy Digital Single Issues

Don't miss an issue.
Buy single digital issue for your phone or tablet.

Buy Single Digital Issue on the In-Fisherman App

Other Magazines

Special Interest Magazines

See All Special Interest Magazines

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Phone Icon

Get Digital Access.

All In-Fisherman subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit mymagnow.com and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now