While the unit has many positive features, anglers should also be aware of its limitations. The SI unit’s transducer must be located externally on the stern of a boat. The system works best at speeds under 10 mph and on straight-line courses, as turns distort the imagery.

How the stern is shaped and the outboard motor mounted influence whether the unit can “see” well to either side. Nothing may be placed in the line of sight to the sides of the transducer, and external mounting exposes the transducer to possible damage. Yet reasonably careful operation avoids damage, even in reservoirs with abundant standing timber and stumps.

Beginners with the SI system learn to better identify echoes and use other features on every outing. If you’re a non-techie, you may find the complexity of menus and some options non-intuitive, but learning the details is rewarding. Users need to buy a map chip and may want another chip to record images for later review on a personal computer.