A near miss that happened between a fast ferry and a nuclear submarine could have turned disastrous:
https://www.expressandstar.com/news/uk-news/2020/07/15/submarine-almost-collided-with-ferry-after-misjudging-its-speed-report-finds/#:~:text=Submarine%20almost%20collided%20with%20ferry%20after%20misjudging%20its%20speed%2C%20report%20finds,-UK%20News%20|%20Published&text=It%20said%20the%20incident%20put,%2C%20in%20’immediate%20danger’.
I would expect that while observing the progress of a fast ferry ambling along at 15 kts, one might consider that it may be fixin’ to accelerate to a higher speed in the very near future given that it’s a friggin’ FAST FERRY!