Pete,

You must have missed my post about the latest software update (3.740) for the 987c Si and other Humminbird units. It’s not listed but the Zoom while in Side Imaging and the Sonar Record features are in there along with the rest of the changes. This is where you would really notice the differences in what the 987 and 997 units can do Si sonar wise.

No directions on how to use the Si Zoom, Sonar Recording and other features on the Humminbird web site and I don’t know if they will have any. You can download the operations manual for the 997 as the directions for these are in there and are the same for the 987.