Quote Originally Posted by CrappiePappy View Post
IMHO -

Given the same depth of water and kHz setting:

SI is almost a 180deg span of sonar ping

DI is almost a 150deg span of sonar ping

SI is best at finding bottom cover and structure within the scope of the distance it is set for

DI is best at finding those things within a narrower range/distance

With that in mind, most people opt for using SI at the console when searching an area, then using DI at the bow for a closer look at target areas. They are better used in conjunction with each other, more so than alone.

Now, that's just my opinion ... and that's from someone that does not have a SI capable unit, only a DI bow mounted unit, and has little to no use for 2d sonar for fishing purposes. My 2d unit is console mounted and used solely for navigation purposes (by me) and depth of water notice to whomever is fishing from the back seat.
Not a bad opinion...
I have 3 SI units and one DI unit - I use the SI far more locating fish and if I have to park over them, the DI unit draws a better picture under me than the SI generated DI images.