(I'm the funny looking kid carrying the PFDs onto the Pier in the blue parka w/ white collar device.)
I was the A-Nav on board, so I helped with all the navigation briefs for Portsmouth. Our air draft under the bridge was calculated to be 3.86 feet, but both times we passed underneath I was chanting to myself "Think short thoughts, think short thoughts." From on deck it certainly seemed like we were going to hit. I certainly breathed a huge sigh of relief once we past and clear.