To add, the boat is only included on the tourist version of the Zürich card. A normal ZVV pass or even a GA does not cover the surcharge, which was the source of quite some consternation.

Then again, I use the boat about twice a year - the only routes where the boat really cuts down on time, rather than being a leisurely scenic option, is crossing the lake around the Horgen - Mannendorf mid-stretch. And 10Fr in Switzerland doesn't go very far anyway