Install the app

You can route online without installing. Install it if you rely on it offline, or want your routes and polars kept.

40kn Sail Router runs in your browser, and browsers may delete a website’s stored data. What that means depends on your device, and it matters most on Apple devices.

Install first, then download. On Apple devices the installed app keeps its data separate from Safari, and an app installed from one browser doesn’t share data with another. Forecasts downloaded in a browser tab won’t appear in the installed app. From now on, open the app from its icon.

iPhone and iPad

In a browser tab on any iOS browser, the app’s data is deleted after 7 days without a visit, including forecasts, routes and polars. Installing is what prevents that.

In Safari, press Open the app at the top of this page. From iOS 16.4, other browsers can do this too.
Tap the Share button.
Tap Add to Home Screen, then Add.

Removing the icon from the home screen deletes the app and all its data.

Mac with Safari

Safari in a tab has the same 7-day rule. On macOS 14 (Sonoma) or later:

In Safari, press Open the app at the top of this page.
Choose File > Add to Dock, or click the Share button and choose Add to Dock.
Confirm the name and click Add.

Apple’s published exemption from the 7-day rule names Home Screen web apps and doesn’t mention Dock apps. We expect the same protection, but we can’t promise it. On a Mac, open the app at least once a week if you are relying on its data.

Windows, Linux and Mac with Chrome or Edge

In Chrome or Edge, press Open the app at the top of this page.
Click the install icon at the right of the address bar.
Confirm the install.

There is no 7-day rule here, but the browser may delete data if the disk runs low unless it grants persistent storage (see below). Installing makes that more likely but doesn’t guarantee it.

Android

In Chrome, press Open the app at the top of this page.
Open the browser menu (⋮).
Choose Install app or Add to Home screen.

Android works like desktop Chrome: no 7-day rule, and low-storage protection depends on persistent storage.

Firefox

Firefox can’t install web apps without an extension, and you don’t need to install to protect your data here. When Firefox asks whether the app may store data persistently, allow it.

Check that your data is protected

Tap the forecast name at the end of the layer bar and open the Offline tab. Once something is stored, the line at the bottom shows how much is on the device, followed by a short status:

Status	Meaning	What to do
`kept`	The browser granted persistent storage, so the data isn’t deleted automatically	Nothing, unless you are on a Mac (see above)
`at risk`	No grant yet, so the data may be deleted if the device runs low on space	Install the app if you haven’t, keep plenty of free space, and check again after using the app for a while. The app asks again each time it starts, but the browser decides
`7 days`	You’re in a browser tab on an Apple device, so the 7-day rule applies	Install the app, then download again in the installed app

Check this status before every passage that relies on stored data. Hover over it for the explanation in the app.

What can still delete your data

Protection stops the browser removing data on its own. It doesn’t stop these:

deleting the app or its icon
clearing the browser’s website data
Delete all offline data… in the Offline tab, which removes forecasts, maps and coastlines; routes, polars and settings stay

Polars, routes and forecasts aren’t backed up anywhere, because they exist only on your device. Keep your own polar file, and export any route you can’t lose as GPX.

Updates

The app updates itself. A new version downloads in the background when you’re online and takes over when you next open the app or bring it back to the front. The switch reloads the app, so what’s on the screen resets. Your routes stay in the Routes list.

Once it’s installed

Continue with Going offline and test it before you leave.