If you can put the laptop
in a place where it wont get wet and see it while you are at the helm
then great, otherwise I would get the plotter, which are pretty much waterproof...the good ones that is. Some of the better plotters have chart cartridges that have almost exact duplicates of the original NOAA charts
. They are expensive though.
NorthStar makes some nice ones. Products | Northstar
If you do go with the Furuno GP32 then make sure it has WAAS (preferabley) or differential. The reason you want WAAS or differential is not necessarily because you need to now where you are withing 3 meters, its more because it creates a much more accurate XTE, cross tack error, which amounts to a much more stable heading line. If you want to integrate it to your autopilot
then it is pretty much mandatory that you will need WAAS or differential.