I have done some homework on fishfinders and have heard you cant go wrong with the garmin 240. I have a Garmin gps and I love it. I plan to get a 240 but should I get the "blue" for trolling for salmon? The cone angles are much diferent between the 240 and the 240 blue. 40/10 for the blue (dual frequency) and 20 deg for the 240.