I have a Humminbird 997csi. I had to get the high speed transducer because the behemoth side imaging transducer would lose the bottom at around 35mph. I have adjusted the HS transducer at least 15-20 times. I have it where it will not pop up at high speeds (over 50MPH). However, I does pop up in rough water. After it pops a time or two it damages the plastic bracket and I have buy a new bracket. I have purchased 4 brackets because of it popping up. :angry::angry: Quite frankly the design is a piece of crap and I am at my wits end!! I was wondering if anyone else had the same problem. Lowrance has a much better design. Those plastic brackets are for the birds!!!!