You may want to watch this video. Turn the sound on.
It's kind of lets you know what a worst case scenario would be.
I can dig up the Transportation Safety Boards investigation if you want it.
You guys know what to do with the DOT's. They wouldn't let me post the link.
I've operated 3 different swing bridges in the Vancouver,BC region for over 25 years. Only once did I come close to swinging the bridge in front of a vessel.
This vessel was a float plane, planing along the water at a good clip when it came out of the glare from the sun in the early morning.
I did call the company and let them know I wasn't impressed with their pilots actions.
All the best.