After reviewing quite a lot of apps of interest to sailors, I've noticed the trend of app developers who have essentially nothing new to offer themselves but who just repackage existing online content to make a profit from selling the app or advertising on the app. That's one of the reasons it's worthwhile reading reviews before downloading any app. Here are some examples. The History of Sailing app primarily uses information from Wikipedia. Marine Weather Right Now repackages weather information from a website that likely is not as accurate as the data you can get in your area from NWS or NOAA sites or the apps that use that data. And most egregious is Nautical Books, which wants to sell you public domain books you can already get for free (read the review to see how).