# Humminbird SI vs DI



## dexterm16

Looking at the new Helix series fish finders . See about a 300$ different between a unit that has mega SI and DI versus the same style with just DI. Question is what are your thoughts on Side Imaging? The Down Imaging seems hard to be without but is the SI needed or just a luxury?


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## polebender

The Mega imaging is incredible! The SI is invaluable in my opinion and well worth the extra $$. If your only getting one unit I’d suggest the SI. If you follow your mapping around creek beds, road beds, points, and grass beds, you’ll be amazed at the structure you will find and drop a waypoint on around these areas with SI. Then after marking the structure you can go back over it with the DI and get an upclose detailed image of what you marked. 

If you are getting this unit to run at the bow then the DI would be best!


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## leeabu

dexterm16 said:


> Looking at the new Helix series fish finders . See about a 300$ different between a unit that has mega SI and DI versus the same style with just DI. Question is what are your thoughts on Side Imaging? The Down Imaging seems hard to be without but is the SI needed or just a luxury?


Depends on the type of fishing you do!!!


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## firemanmike2127

I'd do SI/DI for the bow graph. I fish a lot of inland water + like going new places. SI has helped me immensly when fishing unfamiliar areas. I should add that I have a S/I unit on the dash also. Having the ability to look both directions from the driver's seat & the casting deck is extremely useful under so many conditions. I've not upgraded any of my graphs to a Mega/Chirp unit yet but that will happen sometime this season. Mike


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## crappiedude

Like polebender said SI is more of a searching tool for me and I don't use it as much as I use DI or even 2d sonar. I have older Low units and if I do use SI it's at the console.
If it were me I'd spend the money now and get the unit with both SI & DI because in the long run it will be cheaper. If you don't get it now you'll always have it in the back of your mind and more than likely you'll end up getting it later .
Even though I don't use mine everyday, I wouldn't give it up.


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## dexterm16

So then part 2 of this question. The size vs price difference is crazy on some units . For instance the 7” helix mega SI/DI is $800 but the 8” of the same features is $1200. That’s a $400 difference for maybe an inch ( units are measured diagonally). Is the added size worth that much of an increase ?


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## RMK

the bigger the screen the better. especially when using SI in my opinion. on my helix 7 i often end up just showing one side of the SI so the image appears larger on the screen. i m still learning electronics but i would definitely say get the biggest screen you can comfortably afford. with the new mega and mega+ stuff coming out i imagine you could pick up some used SI chirp finders 1/2- 3/4 the price of new.


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## s.a.m

Not bird but Bass pro and a few other places are selling Garmin echomap plus 93sv for $600 that's touch screen also 9"


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## polebender

Great deal in the Marketplace on a new Garmin with Panoptix transducer! Both brand new for half the cost!


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## Harry1959

I have a helix 7 with SI and DI..... only been out with it a couple times and haven’t learned to use the SI very well. Any good resources for learning to use SI other than the CD that comes with unit? What boat speed works best for SI?


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## crappiedude

dexterm16 said:


> So then part 2 of this question.


I had to ask myself the same thing when I bought my HDS units. I initially bought an 8" for the console and then added a 7" at the bow a few months later. For me the 8" is so much bigger and capable of showing more detail than the 7". I'm happy with my units but I sometimes think of adding another 5" or 7" unit to the bow so I have more screen. The 7" to me is a minimum. It's hard to swallow the extra cost but IMO, it's worth it.
At times I wish I would have bought a 10" for the console.


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## crappiedude

Harry1959 said:


> What boat speed works best for SI?


 I've always used 3-4 mph with a width setting of 3x the water depth. I really don't like going too wide as too much small stuff can become lost trying to cover too much ground.


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## Brahmabull71

Harry1959 said:


> I have a helix 7 with SI and DI..... only been out with it a couple times and haven’t learned to use the SI very well. Any good resources for learning to use SI other than the CD that comes with unit? What boat speed works best for SI?


YouTube has a ton of videos.


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## DHower08

Harry1959 said:


> I have a helix 7 with SI and DI..... only been out with it a couple times and haven’t learned to use the SI very well. Any good resources for learning to use SI other than the CD that comes with unit? What boat speed works best for SI?







The most informative video I've seen yet


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