DI vs. SI

[Big dreams]

I am fixing to purchase one more sonar unit within the next week or so.  What are the advantages of Side Imaging compaired to Down Imaging?  Seems to me DI would be better as you know for sure where the structure is.  For those who have them, what are your thoughts?

[Waterfoul]

Get a unit with both and get the best of both worlds.

[motocross269]

You know exactly where the structure is in DI and SI mode....Just click on the structure and it gives you a GPS coordinate....

I am just getting started with the new Humminbirds so I can't comment which mode is more useful......

[Big dreams]

Get a unit with both and get the best of both worlds.

SI is a lot more expensive.  I wasn't sure if DI would be sufficient.

[thedude]

i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).

[Big dreams]

i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).

That helps a lot.  I did not know how much DI would help where as SI imaging is obvious.  Guess that makes up the price difference.

[thedude]

once you find it with SI - regular graph mode will show you what you want. I thought about DI for the front of the boat, but a regular graph will show you more ( or at least similar info) in terms of fish and suspended bait under the boat. DI really just shows you a different angle of definition in compliment to what you see on the SI -  for instance you might see something that looks like a boulder on the SI - drive right over it and find out its actually a tire or a refrigerator or something.

[Waterfoul]

i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).

Exactly.  I've found things on lakes I've been fishing for years and years that I never knew were there using the SI.

[bigmojet]

I purchased the HB 798 with both SI and DI this year and can definitley say i use the SI a ton more. My default screen I set at regular switchfire sonar on top with side imaging on bottom left and right. I can't believe the amount of cover on my favorite lake there is that I didn't know about until SI. I wish I could afford the bigger screen but this will have to do. If you would be just running DI you would probably never get a full picture of everything down there.

I run this setup on my console with a cheaper non-color sonar up front. I might upgrade to a color GPS model up front that I can network with the 798 si/di next year.

I was reading on some HB forums on the technology behind the differences between DI and SI before I made my purchase and seemed the HB models use the SI information to create the DI image as the SI imaging pretty much covers directly under the boat as well. Many of the users agreed with comments below of using standard down sonar vs the DI for identifying fish.

I'm still am not quite sure how to identify fish on the SI unless it is really obvious (like the fish casting a shadow on the SI).

[SethV]

I hardly ever use DI.

SI is the real deal - use it to locate the structure.  Get over the top of it and use your regular color 2D sonar.  See the fish, hit him i the head, catch the fish.  That simple.

[LennyB]

i find SI way more useful

I agree 100%. SI is great for combing the flats and looking for weed patches, rocks, etc... off to the sides. Two times this year it turned a tough day into a bonanza. Once in the spring and again in the fall.

The spring trip was to a shallow muddy lake were I scanned a small patch of weeds that was about 50 yards to the side of me on a barren weedless flat in 3 feet of water. The water was dirty from the wind so I couldn't spot them by eye until I was right on top of them and that patch was loaded with fish.

The fall trip was the same scenario but it was a rock field way off to the side on a huge shallow flat. 

[REEL_MAN]

If I had to make a choice, SI is the only way to go. You already have the sonar shooting down, but the SI gives you the advantage to find structure way out (and mark it) from the boat not directly under you.

REELMAN

[Big dreams]

You all helped me in making my choice.  Thank you all for your input.  It has been ordered.

[Waterfoul]

What did you order??

[Redbone]

http://www.amazon.com/Fish-Eyes-Underwater-Video-Camera/dp/B004T4RG3M/ref=sr_1_8?ie=UTF8&qid=1321634802&sr=8-8

[Big dreams]

What did you order??

I know there are a bunch of Hummingbird fans here so I tried not to say.  I purchased the HDS 8 and 5 with the Structure Scan.  I use to own a 5 a couple of  years ago and it worked great so I figured I would stick with them.

[Waterfoul]

Oh the Humanity!!!    HDS???       Why!!???!!!   

LOL!!!  Just kidding.  The one drawback I see with the Lowrance units is the need (and cost) of the LSS1 unit needed for the SI.  Other than that they work much the same.  Now you will find all those unknown places the fish hang out and amaze your friends with your fishing skills!

[dartag]

Got a Lowrance Elite5 DSI this summer.  Not that impressed with it.  Works great as a depthfinder and GPS  but the DI was nothing special.  Side scan seems the way to go.  Remember they only work at low speed.  You still need something for high speed running. 

Now the decision is Lowrance or HB.   

[LAPORTE]

After seeing whay kind of service you get at the bassmaster open last year. It's not even a close. HB all the way.... I didn't even see a service trailer for the Lowrance units....

[Big dreams]

I have a small Lowrance in the dash so the HDS will be on the side.  Looking forward to checking out the local lakes that I "thought" I knew to see why the fish are really where they are.  The LSS1 is a bit expensive.  That was almost a show stopper for me and almost made me switch to HB.  But it didn't