Do Humminbird SI's not work on HD boats?

[Missoura Bushwacker]

Long time reader first time poster. I am praying you guys can help. I have been working with several other people on a couple of different forums for about a month now trying to trouble shoot my 798 hdsi. I have about $1300 invested in a single 798 head unit with separate transducers at the TM and the transom/console. I am begging for a solution to several different issues. I am ready to give up on Humminbird if something does not give. It should not be this difficult.

1. I have the transom mounted ducer installed per directions with no obstructions in the way. When traveling at low speeds (UP to 3 mph) I always get a "white cloud" in the top 3 feet of the left side column and most times I lose some the outer image of the right edge. This cloud and missing gets bigger and occurs on both sides of the column at speeds above 3 mph and the whole screen goes static. This happens regardless of whether the TM or the engine propels the boats See pics.
Low speed

Shield placement. I have since even removed the livewell screen just in case

High Speed creates static

I put the ducer on a stick deeper in the water and saw this at low speed.COuld not keep it steady at high speed.

I put the whole system on separate shielded wires and on separate dedicated batteries away from all other electrical sources thing bad grounds or interference/noise was causing the problem but it still does it. Notice in the pic below how you can see where I back on and off the throttle to make the screen static in and out and white clouds get big and little. IT affects the Di and @D as well.


2. The list of similar problems I am having at the TM are too numerous to mention. I will address them if and when I can address the issues above.

3. I borrowed another 798 that works and tested on my system but same probs occurred. We noticed that when running my 798 on transom and borrowed one on TM caused repeating patterns of alternating black and white lines on both screens which went away when one is turned off. CRAZY

Please help. I have tried it all but maybe some one can help. I have a 20 foot express hd aluminum boat.

[reelman]

May be way off but any waves...wake...bubbly will cause those type images...
at least on my 997 and on my 898...

ducer could be too high in the water and very sensitive to waves, etc from the boat...
just a guess...good luck with it...

[Missoura Bushwacker]

Thanks for the input. Unfortunately conditions were calm at the time of the pics.

Anyone else out there with a 798 on a HD20. If so what are your experiences?

[xpress spanky]

Nick,i don't own Hummingbird,but have the Lowrance HDS10 and HDS8 both linked to structure scan on my H51.I also have a 10"CMC jackplate on mine and can tell you with mine i had to build a plate to mount on the bottom of my jackplate to keep the signals from bounceing around inside the plate.My tranducer was farther down from the plate than yours as well.I went to Lowes and got a small piece of diamond plate to make it out of,and just drilled small holes up from the bottom of the plate and used small sheetmetal screws to mount it to the jackplate.The other thing is where you have it mounted,your getting a lot of water disturbance.It would help if it was deeper in the water,and would be in cleaner water.

[kk4iz]

This was how we had our mounted before it got broke off a few weeks back but now we have a TSS bracket but have not tested it yet. I'll let you know if have a problem with it. But looking at yours it looks like it need to be mounted a little closer to the transom, that what they told me to with the TSS. Give Scap a call at TSS ( 334-515-7147) he runs a Xpress and Ranger he'll be glade to help. He's the one that design the TSS

Good Luck and let's us know how it comes out.

WB

[MrTotty]

Try what I did



I moved the lower bracket back one hole and drilled a second hole so it would have two. Works great for me at low speed, no noise, static or anythign.

[kk4iz]

Nick after looking more are your HD boat is not a pad but more like a flat bottom boat, I'm I right? If so a dent, the drain plug or drain hole, anything on the bottom that will cause air bubbles will give false reading.

Nick you might to put some more pictures up on the back of your boat and from both sides and maybe a bottom view. That way we can tell more about it.
Good luck with your problem someone should be able to help you fix your problem.