The 38th Street bridge in Newport is on our gondola route.
Most of the time we can fit under it, and when we can't we know ahead of time because we read the tide measurements on another bridge before we get there. At certain times though, the clearance is questionable; approaching slowly with a "plan B" is a regular practice then. Sometimes simply shifting forward will lower the ferro enough, occasionally I'll ask my couple to move up to the front of the boat to further drop the bow, then back again to lower the tail. Often I find myself "getting creative" to get the tail under.
Of course each gondola is different, recently I had an exciting adventure with the "Lucia" involving the 38th Street bridge - you can read about it in my post "Getting to Know the Boat".
In Venice, gondoliers sometimes tip their boats to starboard to make it under bridges at marginal tide points. Because gondolas are asymmetric, it makes sense to lean to starboard.
Gondolas are not symmetric, and the same can be said for the 38th Street bridge. One side is a little higher than the other. If you approach from the south end of the bridge, and barely fit under the lip, you'll be fine because the ceiling rises a little as you proceed. Come in from the north side at marginal times, and things won't be so happy for you - you'll be grinding and scraping (and probably swearing) halfway through.
Many times I've watched drunken Duffy-boat drivers approach from the north, passengers in the front saying "Oh yeah dude, you're fine!", the driver throttling up, and the canopy frame catching on the underside of the bridge as the ceiling slopes down. It's a really great way to do costly damage to the top of your boat. You can see the scrape-marks on the bridge in the above photo.
I shot this photo a while back using a remote trigger with the camera bungee-corded to the tail. I may look calm and collected in the photo, but two seconds before I shot it, I was nervously making sure that my camera wasn't going to be the next casualty of the 38th Street bridge.