si on the front can be helpful.just one example is if your approaching structure but you don't go directly over it you see on the si which side of your boat it is on.left or right and use that info to make adjustments.now's here's an ideal for you or please and option.you said that you already have a hummibird at the console,if it's a si unit you could get another si unit without the transducer buy one of there strolling motor mount Di transducer buy the buy the Ethernet switch. By doing this you share transducers..each unit would have the ability to share the transducer through the Ethernet switch also later 360 could be added witch also would be shared through the switch..keep in mind tho that hummibird has not said if this would viod warranty or not.