TidePoint - a Tide Times App for iOS
The TidePoint app is an extension to the TideTimes.org.uk website. It is intended to allow you to browse tidal predictions while being out of signal range. The app shows 7-day tide predictions for free with the option to purchase a calendar year's tidal predictions for a location.
All predictions are downloaded to your device while you have a signal. You can take your device out to see or even abroad, and still have access to those predictions. The files are designed to be compact and secure - a typical year-long data file is just 5K and everything is protected with industry standard encrypion.