Hi, is that ferry included in the pass? What I can remember there is only a ship of BLS included in lake Thun. 

Check here validity of Interrail/Eurail in Switzerland: https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.sbb.ch/content/dam/infrastruktur/trafimage/karten/karte-geltungsbereich-InterRail-EuRail.pdf&ved=2ahUKEwj4wu6nlYL_AhWRy6QKHfH0AsQQFnoECBQQAQ&usg=AOvVaw1TSqZOeF9nJc97L2JmJCYS

But you get 50% discount for the ship. For discounted trips you don't have to add it to the pass.

This ferry is not covered by Interrail/Eurail but you get a 50% discount. No need to use a pass day and you don't add it to the app either. Simply show the pass at a CGN ticket counter in Lausanne and they should sell you the discounted ticket.

https://www.interrail.eu/content/dam/miscellaneous/Map%20of%20Switzerland_SBB.JPG

Only boats on Lake Thun and Lake Brienz are fully included (run by BLS, a railway company).

Edit : you may be able to buy a half-fare saver ticket on sbb.ch or SBB app for tomorrow. It costs 7.80 CHF instead of 13 CHF but it is tied to a specific boat. For 1st class a regular half-fare ticket costs 18.50 CHF (no saver tickets)

Hi, is the 50% discount valid for all CGN ferries on Lake Geneva? That map that is linked above does not show the Lausanne-Thonon and the Yvoire-Nyon ferry links, that I am interested in.

It’s not helpful that CGN is not mentioned on the relevant page on the Interrail site then https://benefitsportal.eurail.com/?categories=1be1ba1c-80f5-4286-b255-3092f0d486cd&countries=CH

Thanks! 

It doesn't show all routes nor stops. For example on Lake Thun only Thun, Spiez and Interlaken West are highlighted while there are dozen more piers on the lake.

It's safe to say that the half-fare discount is available to you. Feel free to have the map on hand if you need to show it to staff. :)

The map issued by SBB is way more reliable than the Interrail/Eurail website, don't worry.

You just had the wrong page. Here’s the correct overview: benefitsportal.eurail.com/benefits/swiss-private-boat-benefits/