Dreamt I was a harbour master in a city of glass

I'm standing in a control tower that's all windows, looking out at ships that glide through canals like they're being pulled by invisible strings. The water is perfectly still, no waves, no salt smell. I keep trying to radio the vessels but the only sound is a low hum, like a ship's engine idling far away. I wake up with my hands cupped around my mouth, like I'm still calling out across the deck.