I believe Bottomline was working on a primitive form of SI. Humminbird bought both Zercom marine and Bottomline out. I believe the technologys these companys had are now found in the Humminbird product.
Humminbird today is by far a much better graph than they were just 10 years ago.
My personal experience is that Lowrance quality has really tanked. I loved the old x75 I had wish I kept it. Lowrance don`t make them like they use to. My x510c was garbage.
