If you can swing it buy one that has GPS as well, easier sell for "safety"
. It will give you an accurate speed even if you are drifting(not moving forward) and many have temp included. And a 50/200 or even 83/200 transducer wouldnt hurt for salt water fishing. Downside is cost. Bass pro had HDS 5 Gen 1 base for I think around $700 with rebate might have been less(dont remember exactly)Give them a call. It is an awesome finder with built in GPS though.