An easy-to-use tide app that gives you the info you need without relying on cellular or WiFi connections: location; date and time; a 24-hour tide or current graph; tide height, current speed and direction, sunrise and set times; and moon phase, rise and set times. MyTide is free and is available for iPhone at the App Store (Android support is coming soon).
https://itunes.apple.com/us/app/mytide-tide-currents-for-sailors/id859628577?mt=8