Which routing software are you using? 

Testing with the routers on openstreetmap.org, the ferry is used for foot routing in both OSRM and Graphhopper (see e.g. https://www.openstreetmap.org/directions?engine=fossgis_osrm_foot&route=50.6394%2C-117.9250%3B50.6059%2C-117.8694#map=14/50.6224/-117.8965&layers=N) and for bicycle directions using OSRM (https://www.openstreetmap.org/directions?engine=fossgis_osrm_bike&route=50.6394%2C-117.9250%3B50.6059%2C-117.8694). Only Graphhopper bicycle routes around the lake.

The way might just need a bicycle=yes added to help out Graphhopper (and if you're doing that, can also add fee=no)