Question about side imaging

Maybe someone on here can give me an answer before I plop down $800.00. I have a Helix 7 DI (without GPS) in front of boat with transducer mounted on trolling motor. I would like to replace the Helix 7 DI with a Helix 7 SI (with GPS). But I don't know if the SI will work with the transducer mounted on the trolling motor since the trolling motor is used to steer the boat. I know they take images of the bottom in different ways and have watched a couple of YouTube videos but have not seen an answer to my question. Any help will be appreciated. Thanks in advance.

SI on the TM is a valid option as long as one realizes that turning the TM quickly will skew the new SI data being plotted at the top of the SI image... (It doesn't change the SI history data farther down the SI image that has already been plotted in the SI image) ...

Keeping the TM movements slow (and preferably with the boat tracking straight ahead) when needing to discern structure/fish is the goal ...

And then plan the TM movement when there's nothing coming into the new SI data (at the top of the screen) that needs to be studied ...

Rickie

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Originally Posted by Pastor

Maybe someone on here can give me an answer before I plop down $800.00. I have a Helix 7 DI (without GPS) in front of boat with transducer mounted on trolling motor. I would like to replace the Helix 7 DI with a Helix 7 SI (with GPS). But I don't know if the SI will work with the transducer mounted on the trolling motor since the trolling motor is used to steer the boat. I know they take images of the bottom in different ways and have watched a couple of YouTube videos but have not seen an answer to my question. Any help will be appreciated. Thanks in advance.

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As long as you're going in a straight line, you will get the same results as if the transducer was mounted on the transom. Turn the trolling motor in the slightest degree and your screen image will be skewed temporarily (just like your DI screen image does).

SI is basically an expanded DI ... the narrow fan shaped sonar signal just reaches out at a far greater angle/distance on the SI. That sonar signal is sent out at right angles to the forward facing transducer, so if the transducer is on the trolling motor ... you're signal direction depends on the direction of the trolling motor head.

As I understand it, SI images are best when you are moving at a couple of miles per hour ... but, I do know that many members do have SI units on their trolling motors, so it must work OK at slower speeds. I don't know, as I don't have an SI unit ... just a DI unit, with the transducer mounted on the trolling motor.

SI on the trolling motor is a great tool. For example.....sometimes fish don't hold right on a brush pile. If you approach the brush with SI, you may see the fish of to one side or the other.....You can also move the trolling motor to scan around. Sometimes you will spot other brush off to the side of where you are fishing.
I have seen some really good images at very slow speeds on a trolling motor.....reducing the chart speed will keep the scale on the screen more accurate.....but it's not necessarily about pretty pictures .... it's about having more information.

Thanks for the replies guys. Now all I have to do is decide if I want to drop that kind money on a Helix 7 SI for my wife's valentine's present. Hehehe!

Haha!! It depends on how much you like the couch I guess.

Not to hijack, but how does DI work on the trolling motor when your moving and turning the trolling motor constantly. Like when your trying to hold over a deep brush pile in the wind.

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MATHEWJP,I DO IT WITH 2D AND DI ALL THE TIME,ONE WILL HELP THE OTHER UNIT,LIKE ALREADY SAID NOT BEST PIC BUT BEING IN BOAT WHILE DOING IT THE INTERPRETATION IS NOT THAT HARD,CAN TELL FISH FROM BRUSH AND WHAT MORE WOULD YOU NEED

Being DI is a very narrow beam there is no way to tell how the fish react to your presentation, cannot keep the jig in the beam. That is why when I am fishing vertical I use 2D I can see my jig and watch how the fish react and tell me how to change presentation or bait. Me personally DI is worthless because I have used SI to know the fish are in that spot before hand unless it is ultra shallow.

BRICK,I AM SORRY TO DISAGREE WITH YOU,I BEEN USING 2D AND DI AS LONG AS THEY CAME OUT,I FISH OVER BP MOST OF MY FISHING AND DOCKS THE REST,DI WILL LOOK INTO BP WHILE SETTING STILL WHILE 2D SEE THE FISH OVER BP YET I SEE FISH IN BP WITH 2D AND DI,YOU JUST HAVE TO KNOW HOW TO INTERPRET,FISH LAST WEEK IN BP NEAR A BLUFF AND THE FISH MOVED SO I MOVE TO BLUFF ABOUT 15 FEET AWAY,COULD NOT SEE FISH NEAR BLUFF WITH 2D BECAUSE 2D PICK UP BLUFF FROM 15 T0 35 FEET DEEP,SO I TURN DI SO IT WOULD BE GOING WITH THE BLUFF AND IT THEN WENT TO 35 FEET DEEP AND I COULD SEE THE FISH AT ABOUT 28 FEET DEEP AND BEGIN TO CATCH THEM AGAIN,THESE UNITS WILL TELL US MORE THAN WE THINK THEY WILL,JUST HAVE TO LEARN WHAT IT IS TELLING YOU,I GO OVER BP AND DI TELL ME IF FISH ARE THERE AND ABOUT THE SIZE SO I KNOW WEATHER TO STOP OR NOT UNLESS IT IS A THICK PILE ,THEN I HAVE TO FISH IT ALSO,I DO BRIDGE PILINGS THE SAME WAY WITH DI IF THEY CLEAN TIGHT TO THE PILING,CAN SEE THEM WHEN 2D WILL NOT SHOW ANY

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Originally Posted by mathewjp

Haha!! It depends on how much you like the couch I guess.

Not to hijack, but how does DI work on the trolling motor when your moving and turning the trolling motor constantly. Like when your trying to hold over a deep brush pile in the wind.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

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If you turn the trolling motor slowly, it won't mess the image up much ... but if you have to turn it quick or often, then the image will be broken up on the screen. You have to also understand that a DI sonar ping spread is fan shaped and not cone shaped like 2d sonar. Every direction change turns the fan shaped sonar ping, so you're getting readings in a narrow band 90deg to the left/right of the transducer ... and 2d sonar, being a cone shape, whichever direction you're heading, then the leading edge of the cone is in front ... even if you're going in reverse.

Here's what a DI image looks like when you have to change directions quickly, as in this case I was going through a stand of submerged cedars and had to dodge a cedar stump (DI tdx is on trolling motor) :

Attachment 258318

Please forgive the image clarity, as I had just started using the unit and did not have it dialed in. Plus, I didn't really like that palette color and changed it shortly thereafter to the blue palette color ... so I could get images like these :

http://www.crappie.com/crappie/attac...lotter-005-jpg

http://www.crappie.com/crappie/attac...-screen002-jpg

With a combination of 2D and DI, you will be able to tell when you are positioned exactly over a brush pile......because of the narrow beam, it won't show on DI till you are right over it .... and the presence or absence of it on a 2D beam will tell you if it is off to the side.

Thanks for the info, guys.

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Yes, thank all of you for the information on both DI and SI. I have learned a lot.

HAve 2d and di on tm. When I sit still over BP my di is just a blur. When moving picture is perfect. What am I doing wrong?:dono

the Down imaging is like side imaging, you have to be moving to get a good picture.

AS SAID,DI DO NOT GIVE GOOD PIC WHILE SETTING STILL HOWEVER YOU STILL CAN USED IT TO YOUR ADVANTAGE,IT WILL SEPERATE THE LIMBS AND FISH BETTER THAN 2D UNLESS IT IS A THICK BP,YOU WILL LEARN IF YOU ARE SEEING FISH OVER TIME WITH IT ALSO WITH ITS WIDE BEAM IT WILL SHOW BP OR FISH WHEN YOU GET OFF BP A LITTLE AND IF YOU WILL TILT YOUR DUCER A LITTLE TO FRONT THAN WHEN 2D START LOSING BP YOU TURN TM AND IF IT STARTS GETTING STRONGER THAN THAT IS THE WAY TO GO TO GET BACK ON TOP OF IT,ALSO WHEN YOU ARE SEEING BP STARTING TO COME ON 2D AND NOT DI OR GOING OFF IT THEN YOU MAY BE SEEING FISH THAT ARE SIDE OF BRUSH AND YOU WILL KNOW WHERE THEY ARE AND THE DEPTH THEY ARE AT AROUND THE PILE,AS BEEN SAID BOTH UNITS HELP EACH OTHER FOR YOU TO GET BEST INTERPRETATION,ALSO WHILE FISHING BP YOU ARE NOT AFTER GOOD PIC BUT WHERE THE FISH ARE IN RELATION TO BP

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Originally Posted by crappie flash

HAve 2d and di on tm. When I sit still over BP my di is just a blur. When moving picture is perfect. What am I doing wrong?:dono

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As stated by others, that's perfectly normal. You have to have movement with the DI to get those nice images ..to some extent 2D is the same way.

It's all about information, sometimes pretty pictures don't matter ..... When you see the BP on DI and 2D both ....you know you are directly over it.