Routing: Ship route over the lake instead of on land

During my last circumnavigation of Lake Constance, I set a vehicle point while on the crew. The point was along the lake on the other side, but not directly opposite. The routing then showed me a route as usual.

However, the shortest route was directly across the lake. So it took the shipping route instead of the roads. It's kind of nice that it recognizes the shipping route. However, I would prefer to ride a bike. Maybe that should be adjustable somewhere.

Here’s a link to the photo:

https://cleanshot.com/share/ZKzbYMwS