Humminbird 858cdi Depth Reading Problem

[KAG]

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......



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

[rnvinc]

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

[KAG]

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

[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

[KAG]

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

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

[rnvinc]

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

[gobbler]

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

[rnvinc]

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

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

[Humminbird_Greg]

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.

[HBirdDeborahCRC]

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