Even though it’s en web app built in HTML5 and Javascript, it’s still possible to make it work offline. Off-course, it depends on your browser and device but all major browsers are known to support this technique.
Notice that even if the app works offline, services like weather data and show position on map depends on internet connectivity.
Install app on iOS
On any iOS device, all you have to do is:
- Start Safari and enter the url http://jonika.nu/NautiCalc/
- Hit the “Share” button
- Select “Add to Homescreen”
Android devices running Firefox
Most versions of Firefox seems to ask if you to allow the site and/or web app to be cached on your system. If you allow, you should be able to use the url even without internet access.