Stephanie Rolfs, like many Bay Area residents, has spent a lot of time looking out over the bay, watching as ships come and go. The cargo ships in particular are so big and obvious as they sit out in the middle of the bay, south of the Oakland-San Francisco Bay Bridge and north of the San Mateo bridge. She wondered, how do those ships know where to park? Are there invisible parking "spots" they're pulling up to? How does it all work out there? We called Vessel Traffic Services to find out.Additional Resources: Welcome to Anchorage 9: The Giant Ship Parking Lot You Pass Every Day Read the transcript for this episode Why Specialized Mariners Are Required on Every Ship Sailing Into San Francisco Bay Sign up for our newsletter Got a question you want answered? Ask!Your support makes KQED podcasts possible. You can show your love by going to https://kqed.org/donate/podcastsThis story was reported by Katrina Schwartz. Bay Curious is made by Katrina Schwartz, Christopher Beale and Olivia Allen-Price. Additional support from Jen Chien, Katie Sprenger, Maha Sanad, Ethan Toven-Lindsey and everyone on Team KQED.Learn more about your ad choices. Visit megaphone.fm/adchoices