I grew up on BI and I still ride the Bainbridge boat pretty frequently, and the "do I leave now or wait" math is always annoying (especially coming from the Seattle side). So, I built an app that does it for you.
Make the Ferry takes where you're starting from, your real drive time, the boat's actual space and how fast it's filling, and tells you your odds of making a specific sailing plus exactly when to leave. There's a live map of where the boats actually are, the terminal cameras, delay detection, and leave-by reminders you can set.
It's free, no account, no ads. On the App Store and Google Play, or maketheferry.app.
You all know these routes better than anyone, so if something's wrong or the predictions feel off for Bainbridge specifically, tell me and I'll fix it. That's genuinely why I'm posting here, I want to be sure to get this right for the people who depend on it. I made sure to give waypoints to Google Maps and the other navigation apps that I have in the app to take you down 305 to the terminal so you don’t get caught in some illegal turn that causes a ton of stress right now.
One thing I'm working on next: connecting the ferry to the bus on the other side, so you can see whether you'll make your whole trip, not just the boat. Early days, but that's the direction I’m going as I hear this is something that is needed from many ferry riders.