I completely disagree with the statement that SI units aren't good at the trolling motor. I have a 798 ci si on the trolling motor & a 581 I 2-D unit at the console. You can simply adjust scroll speed either up or down as needed & also adjust noise filter if your getting interference lines on the display. Also if your really busy turning the head of the troller a lot it will skew picture some, but the images still pop out at you. You can adjust scroll speed some to help with this. You can also turn troller head very slow to scout things out like shooting under docks & such. When I was buying an si unit I read many comments just like Crappy-Pappys( no harm meant towards you pappy) & almost put my unit at console, but after reading & looking at images on Bass Boat Central (www.bbcboards.net) & the unofficial humminbird forum I put my si unit on the trolling motor & really glad of it. Another thing with it being up front is when trying to fish an offshore waypoint you've marked with the si unit on trolling motor is you'll always be facing towards your waypoint. Si up front can also show you if a large school is just out of range of your cast as a big school can only be 10 or so feet out of your cast range & you'll know it with si up front. Di & Si both work extremely well up front after you get used to operating them. Way better than just at the console & honestly10 to 1 in my opinion. Why not have both where you fish most times ???