Humminbird 858cdi Depth Reading Problem

Ok read posts, read the on line manual....still have an issue.

Ok installed the 858 yesterday afternoon, on the lake today. When I come up to speed the depth jumps all over the place, when I slow down it reads fine. Played with various settings and still present. There is poor 2d readings as well.

Took a photo of how I have it mounted, I loosed up the screws adjusting it and have not straightened it back up yet.


Thoughts......

Attachment 99757

I also ordered one of these transducer mounting plates so I stop putting holes in my boat

Attachment 99758

Either the xducer is coming completely out of the water at speed or there are bubbles being created by the boat hull...Sonar will not read thru air...

You can try...

Tilting the back of the xducer down a degree or two...
Lowering xducer a fraction of an inch...
Move the xducer to different place on the transom into "cleaner" bubble free water..
Install a thru hull xducer with a Y cable to get high speed readings..

Lots of guys here been thru your same issues...some probably with the same boat hull setup...

Rickie

At speed I looked back and can see a clear transducer water wedge trail directly behind it.

I'm sure someone with that boat hull design will jump in with good advice..

I would guess the xducer is going to need to be moved down some toward the livewell screen...

The mounting board you pictured is a very good way to test different spots on the transom...

Be patient...you'll get it dialed in...

Rickie

Quote:

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Originally Posted by rnvinc

I'm sure someone with that boat hull design will jump in with good advice..

I would guess the xducer is going to need to be moved down some toward the livewell screen...

The mounting board you pictured is a very good way to test different spots on the transom...

Be patient...you'll get it dialed in...

Rickie

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Thank you so much for taking a look. It helps getting in put on frustrating issues like this.

Each hull design seems to have a "sweet spot" for getting good high speed readings...

I would also guess some hull designs are just nearly hopeless for a "sweet spot"..

Just realize it's a process of elimination...trial and error...

And then there is always the option of the "thru hull xducer" on a Y cable ...

This option is advantageous in the ability to get high speed readings from the "thru hull xducer" and allow the more expensive DI (or SI) xducer to be mounted a little higher on the transom where it is more protected from floating debris...

HB even lists this option for 2d and DI from a "thru hull" xducer...(you wouldn't be able to get water temp on a stand alone "thru hull" without some sort of temp probe in the water)....
XIH 9 DI T

Rickie

i am not sure that the humminbird thru hull ducer will work on a aluminum hull

Quote:

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Originally Posted by gobbler

i am not sure that the humminbird thru hull ducer will work on a aluminum hull

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Ahh.. You are correct gobbler... I didn't even notice from his pic that his boat was aluminum..

KAG.. The HB thru hull xducer is probably not an option for you...

There is this third party xducer option for the 2d high speed readings ...but I know nothing about it except what the vendor claims...
AlumaDucer

Rickie

Not an option either Rickie as the AlumaDucer will not work with the DI sonar units due to their different design. I think that you are correct though in that the transducer will probably work better if it is mounted closer to the centerline of the boat. This will put it deeper in the water at all speeds. I have even seen where some have doubled or tripled the transducer mounting boards so that the transducer sits farther away from the transom. One of our aluminum work boats used a two-inch think piece of Delrin (it’s what we had on hand) for some of the transducers and it allowed us to get depth readings at WOT.

Until you get the mounting plate to relocate the transducer you may try to tilt the transducer @ 7 degrees down to see if that helps at the higher speeds

Thank you so much for the input, it helps a lot.

This is just me.....I would think a world leader in fishing electronics would kind of have this worked out with transducer placement. Especially on the spendy versions of electronics. I mean I know there are many different boats but not that many truly different Hull designs.......

I am just going to let the boat sit until the mounting plate gets here on Wed and then I will move it farther down towards the live well fill screen. I will seriously look at doubling up the mounting plate.

I wonder if some of the synthetic decking boards would work for a mounting plate if was cut down???....I mean its water proof and synthetic composite. You can get a long piece of 5/4 material for what a small mounting plate costs.

Maybe a sticky needs to be made of just correct transom mounted transducer placement photos with boat make, model, and electronics.

Like this:

Lund 2012
1825 Explorer
Deep V Aluminum
Humminbird 858CDI

...............just a thought

Make sure the screws you use to mount the transducer to the mounting board are NOT longer than the board is thick. You'll have holes in your boat that you don't want. Had a buddy went to all the trouble to mount the board then punched holes in his boat with the screws! :Doh:

Quote:

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Originally Posted by Wiskers

Make sure the screws you use to mount the transducer to the mounting board are NOT longer than the board is thick. You'll have holes in your boat that you don't want. Had a buddy went to all the trouble to mount the board then punched holes in his boat with the screws! :Doh:

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Roger that

Quote:

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Originally Posted by KAG

Thank you so much for the input, it helps a lot.

This is just me.....I would think a world leader in fishing electronics would kind of have this worked out with transducer placement. Especially on the spendy versions of electronics. I mean I know there are many different boats but not that many truly different Hull designs.......

I am just going to let the boat sit until the mounting plate gets here on Wed and then I will move it farther down towards the live well fill screen. I will seriously look at doubling up the mounting plate.

I wonder if some of the synthetic decking boards would work for a mounting plate if was cut down???....I mean its water proof and synthetic composite. You can get a long piece of 5/4 material for what a small mounting plate costs.

Maybe a sticky needs to be made of just correct transom mounted transducer placement photos with boat make, model, and electronics.

Like this:

Lund 2012
1825 Explorer
Deep V Aluminum
Humminbird 858CDI

...............just a thought

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Good idea KAG. Maybe you can get the site Admin to set this up. The closest I have seen to this are the installation photos on the UnOfficial Humminbird Side Imaging Group web site.

There are not that many different main hull designs but there are many different variations within each. Example: Aluminum deep-vee hulls come in a variety of dead rise angles, some are welded, some riveted, some have lifting strakes, trim tabs, various sizes of motors, kicker motors, and on and on. Generally the best area to mount the transducer is as low and centered as possible while also not causing any water flow issues for propeller or the motor’s cooling water intake. That ‘general’ area varies quite a bit for each boat hull and even if the hulls are the same it can vary by how the boat is set up and loaded. I do wish there was a one place fits all installation location – it would sure make it easier on us as well as our Customers!

Even tho we often seem to get overwhelmed with stickies I have to agree that this is a good idea for this particular subject. If someone will make a sample post covering all important install information AND pictures of their installation I will set up the sticky. Please PM me when this is done so I will see it sooner.

When my mounting plate gets here tomorrow I plan to work on the transom mounted transducer. I will post what transom position ultimately works on my Lund.

As the sticky data base grows it should really help folks like me. As another idea it should only contain photos with brief data.....not a long drawn out thread chain with limited information and lots of posts, that would defeat the purpose....or so i think