We had a Seaway 24' built to our specs. Love it. Took her out on her maiden cruise on Saturday. I had Eastern Boats hook-up my Honda BF150 w/ a NEMA 2000 cable to the Garmin 720S. I cannot get over all the information you get from it! It's insane! I forgot to hook-up my lanyard & the 720S told me it wasn't conntected!
Having so much fun playing around with the 720S. It's so damn easy to work. I also have this weather station networked into the GPS. Real cool in it's own right. https://buy.garmin.com/shop/shop.do?pID=15014&ra=true
I highly sugguest getting a NEMA 2000 cable if you're buying a new or used boat. It's cheap & well worth it!