I have a nitro Z7 that I'm taking the lowrance's off for the hummingbirds I took off old boat . I have a HB 998c SI , a HB 858c DI and I'm buying a 3rd HB for the flush mount dash . Also getting Minnkota Terrova trolling motor . Wanted to put the SI on trolling motor , the DI at console and buy the 798 SI for flush mount dash but I guess you can't have the SI on shoot thru hull . I really want to have SI at trolling motor but I need it at dash too . Any suggestions ? Thanks for your time fellas ! Much appreciated ..

Why can't you have it both places? You can mount it on the transom, pad, or jackplate. SI installation on the Terrova is relatively simple as well.

I have a nitro Z7 that I'm taking the lowrance's off for the hummingbirds I took off old boat . I have a HB 998c SI , a HB 858c DI and I'm buying a 3rd HB for the flush mount dash . Also getting Minnkota Terrova trolling motor . Wanted to put the SI on trolling motor , the DI at console and buy the 798 SI for flush mount dash but I guess you can't have the SI on shoot thru hull . I really want to have SI at trolling motor but I need it at dash too . Any suggestions ? Thanks for your time fellas ! Much appreciated ..

Yes a SI transducer has to be exterally mounted.

IF you can still find a 798 in any of the three versions, (they are discontinued), it can be installed with the SI transducer on the transom, a shoot-thru 2D transducer XP 9 20 and the two transducers connected to the 798 display with the AS SIDB  Y cable.

If you get the 798ci HD SI, you can connect it and the two other units together with Ethernet and use the transom SI setup or the trolling motor SI transducer to be used by either SI unit. All of them can share GPS data.

 

BTW, the DI transducer can be installed as a shoot-thru.

 

If you need more details, just PM or email me. I am very familiar with setups like you are considering.