Question for Humminbird Greg

[Allen Coker]

Hi Folks, Al in Alabama here...new Web Site member. I've been told that "Humminbird Greg" is the guy to answer this question, but I'll take any other suggestions. I have a new 788ci HD DI. Can you get a good DI image with the transducer mounted in the bilge? I tried this past weekend using the "bag of sand and water in the bilge" temporary installation method, but could not get a decent DI image. I got good 2D sonar images and was able to maintain on-plane depth readings up to about 50mph, but again, poor DI. Should I mount it on the transom with a tranducer shield or go with a second shoot-thru transducer and a transducer switch?



Any other suggestions?



Thanks,



Allen

 

[Jeffry Skidmore]

I'm not Lisa......... but;



IMO your best bet is to get another transducer and use a "Y" cable. The unit will read the sonar/ DI separately as needed.



I have a 798ci SI/DI at the bow and have a separate transducer for it. I have a 998 at the console and a transom mount and a shoot-thru hull puck for on plane readings connected with the "Y" cable and it works fine.

 

[Wayne P.]

js, I don't think that is applicable with a DI unit.



Also the Y cable is not an "as needed" connection.

It is electrical wiring only with conductors connecting the sonar crystals to the display and none of them are parallel connections. The SI plug connects the left and right SI crystals and the temp sensor to the display and the 2D plug connects the shoot thru 2D crystal to the display. The SI transducer 2D crystal has no electrical path.

 

[Scott Hammer TOXIC]

I would have to say to get the best performance, you will need another puck mounted externally. Put it on the transom with a shield is my suggestion.



TOXIC

 

[Humminbird Greg]

Hmmmm, good questions here. I will have to check on using the AS-SI-DB-Y cable with the DI unit or not. Electrically I think that the connections would be good but I want to make sure before suggesting for someone to do this that it does not make an electrical problem with the DI units as they are a bit different than our other units.



Allen, when you tested the transducer inside-the-hull; did you sand down the area so that only the raw fiberglass was present? Typically what will block the Di sonar will also block the 2D sonar. If you were able to get good depth readings at high boat speeds you should have been able to get good DI sonar readings. You may also have to try several different locations inside the hull and in this instance: an inch one way or another can make all the difference here.



By the way, do you know that this unit and transducer are working correctly? Try temporarily mounting the transducer to a pole or something that can be held over the side of the boat while moving at slow speeds and see if you can get a good DI image then as it could be the menu settings you were using or even the boat speed as opposed to the transducer location.





Greg Walters at Humminbird

 

[Allen Coker]

Greg/All,



Thanks for your quick response.



Yes, the head unit and DI transducer are working correctly...I mounted the transducer on the transom and got great DI/2D sonar, but poor depth readings on-plane (as expected).



I then tried the AS-SI-DB-Y with a shoot-thru puck dual-beam transducer, but got no 2D sonar at all (I already had these items from my old unit, a 787c2 and know they worked). I went back and reviewed the owner

 

[Humminbird Greg]

Allen,

First off I would check the DI transducer and unit again. Connecting any other transducer than one of the DI transducers that was made for this unit could damage the unit. You need to make sure that your unit is still working properly after connecting it to the DualBeam transducer and AS-Si-DB-Y cable.



If your unit works fine than your only other option is to start sanding.





Greg Walters at Humminbird

 

[Allen Coker]

Greg,



The DI transducer is good, I checked it back on the transom. Will get to sanding...



Thanks,



Allen

 

[Humminbird Greg]

But did you test the DI transducer on the transom after you tried using the AS-Si-DB-y cable and DualBeam transducer Allen? If using these caused damage to your unit you would want to know this before thinking that the DI transducer will not work inside-the-hull of your boat.



Greg Walters at Humminbird

 

[Allen Coker]

Greg,



I did try it after the AS-Si-DB-y cable experiment and it works fine. I did a little sanding in the bilge per your recommendation and tried it again as a shoot-thru with better DI results. Weather permitting, I'm going to spend tomorrow moving the transducer from the bilge to the transom to see if I can get any additional improvement.



At this point, I can see me ending up with two DI transducers connected with a TS3 switch, but would like to avoid this extra expense if possible.



Thanks again for your help,



Allen