I love my iPad. I love it so much that I don't want it to have an untimely death. As a planning and research tool it is outstanding. Within cell phone range you can get weather forecasts, book flight tickets and get e-mail for a reasonable fee, which you can cancel and leave dormant at any time (I HATE monthly fees). Must have apps include;
Charts & Tides WITH Active Captain.
If you haven't seen Active Captain you need to. The Charts and Tides app, while not perfect, allows you to download AC onto your iPad for offline use. The content is excellent and getting better all the time. I wonder how long it will be before they (or whoever purchases it) starts charging.
At 3am, when the seas get up and you get hit by a squall your iPad (and laptop) should be safely tucked up asleep in its bunk. In the cockpit should be your trusty Garmin (or whatever) plotter which is bolted on and is somewhat weather proof. You can go to all the effort of encasing the iPad in a plexiglass covered case but that defeats the touch screen benefit of the unit. My iPad will be secured at the chart station and only venture up on fine days or at anchor.
Just my 2 cents worth.