The SailTimer app is free. You can import the excellent Navionics charts with in-app purchase, or use the built-in land maps and aerial photos. Display your route through multiple waypoints.
Compare 3 different types of marine weather animations: crowdsourced wind maps with NOAA GRIB (US model), AI forecasts (European model), and Weathernews Inc. (WNI) marine weather for ships (Japanese model). When they are all consistent, you know your routing is based on accurate information. Each has a low-cost in-app subscription and 7-day free trial.
Update tacking results automatically as the wind changes, with our solar-powered, wireless Wind Instrument.
SailTimerWind.com
Waterproof hardcases for your tablet or smartphone: Lifeproof, Griffin. Hardcases with mounts: Hitcase, Dog and Bone. Canadian Yachting has some other good choices.
Cockpit mount such as MagConnect with waterproof hardcase, universal waterproof case mount, or RAM Mounts. Plus more in Canadian Yachting.
If your tablet does not have GPS, wireless GPS antennas are available such as the ones from Dual, Bad Elf and GNS.