I've used iphone navionics up to 10nm offhore (WA & Qld) - Just for refernce, it works fine. Iphones - Even in cases - are not particualrly waterproof or robust, so if you do venture far from the coast, i would recomend you use a purpose built marine gps / plotter, and keep the iphione / ipad just for reference. They are fantastic when you are on land for dreaming / plotting your next ocean voyage

Poods