I am in the process of replacing my existing separate knotmeter and depthmeter with a multi-function knotmeter,depthsounder, thermometer and trip log. My old units failed. The question I have is there any other "must have" electronics I should consider purchasing and installing at the same time. These are going to be installed at my wheel since I like to keep the bulkheads clear for leaning. I currently have the Garmin48 with a cigarette adapter as well as a handheld VHF radio in addition to the mounted one below.