Being that you have a Humminbird Helix on the console you will probably want to stay with another Helix on the bow. I'm going to surmise you probably have a Minn Kota troll motor?
The two Helix's can have a network cable run between them so they can share info, transducers, images, maps and position data. Depending on what model Minn Kota troll motor you have, it can also communicate to the Helix units as well as Humminbird and Minn Kota are compatible with each other.
Every brand builds basically the same units with like features but calls them different names. I.E. Garmin forward facing sonar they call the trade name "Livescope"
Humminbird calls it "Mega Live". Lowrance calls it " Active Target". But that features does the same thing on all of them.
Garmin invented forward facing sonar (FFS) and many feel they have the best resolution and technology for that feature.
The FFS feature on all of them shows real time images of what the transducer sees…. Either looking straight down or forward of the transducer. It is not a delayed image like the down scan or side scan or standard sonar images. So you can actually see a real time present image on the screen of fish swimming around brush, tree limbs, etc. You can cast your bait out and actually see it and the reaction of the fish to it. It has a very narrow band width or " field of few" , for lack of better terms.
The downside is FFS does not make good images if the boat is moving moderately… it is basically used once you actually find fish and to be able and look at a specific target area.
Side Scan shows images to the right and left of your boat. So you can travel down a creek bed and look on the left and right side simultaneously to find structure and fish.
You can look under docks, pilings, trees, brush, rocks etc to identify fish, bait fish. The boat is typically moving about 2-3 mph and it is "scanning" that water column on both sides of your boat or you can select one side or the other independently. Side scan takes some learning curve to learn to interpret the images but it is a great tool for searching for cover and fish. Sidescan transducers are typically mounted on the transom of the boat so they stay aligned with the direction of travel of the boat.
Down Imaging or Down-scan is a detailed wide angled beam looking either straight down from a transducer on the troll motor, or straight down under the boat from a transom mount transducer or a thru-hull transducer. It shows greater detail than standard sonar signals.
Most navionics manufactures build transducers that can be used for both side scan and down scan applications… so you only have to mount one transducer.
Sonar gives a good image that is not as detail as downscan but it is a very fast signal so the boat can be moving at a fast MPH and the depth and bottom contours, some structures can be seen.
There are uses and conditions for all four types, just depending on what your application need is that will determine which you will use.
In my oppinion, and that only…… no one brand does all the livescope, side scan and downscan perfectly.
Humminbird invented side scan so they do real well at side scan technology. Garmin has a great " livescope" capability. Lowrance has a great picture quality in downscan and sonar. They all will get the job done.
I personally run Humminbird as my console and bow units in side scan and sonar/ downscan but use Garmin for my FFS unit on the bow as well. The boat I have came standard with Humminbird from the factory as OEM. If it would have had Lowrance I would just do the same set up as above.
Humminbird Helix's are easy to learn and operate imho.
But it is usually what a person learns on that he likes the best….. so.
You can always add the FFS capability to any brand unit you buy later…if you initially purchase a unit that is FFS compatible.
Personally my console unit is used for side scan, down scan, sonar and mapping. My bow Helix can share the same transom transducer as the console Helix (for side scan) and it can also share GPS mapping from the console Helix….. but then the bow Helix can be switched to the troll motor mounted transducer for down scan and sonar images right under the troll motor.
Try to get the largest screen size you can afford for the bow because it will be a long distance from your eyes.
This is all clear as mud right? Hope this helps a little.
I'm positive some other good input will be given by others.
Main thing is it will be a pretty long learning curve to get really good with navionics….. don't get too caught up in it while fishing…. Just set goals to learn a little each time or you will end up spending all day messin with them and your wife and kids will be bored horribly.
Just learn the basics first…. How to turn them on and off…. How to get a sonar image and depth, water temp and speed…. Then fish. Don't try to learn it all at once.
And have fun.
