Edit: oh damn you said that long time ago. I don't know how I missed that.
We started out on a 8 day trip and put in on the Chemung River just above the border in New York which empties into the Susquehanna. This canoe was behind the one I was in. While going under I-86 we hit the I beam but bounced off, we also had a canoe with hevier gauge aluminum but it left pretty good dent and gash but didn't penetrate. The I beam was just under the water but barely a ripple, I'll assume it was from construction of the bridge. The corner of it was sticking up like a can opener just waiting for a boat to hit it. Very narrow passage.
My buddies who were in this canoe ran up on it, it cut the canoe open instantly. They came off it and were still sitting in canoe but it was under water as it was only like 2 or 3 feet of water. Actually quite a humorous site.
Luckily I-86 is not pure interstate and when we up to top of bridge there was a store about 1/4 of mile down the road. It was about 4 pm so we decided to just make camp a short ways down the river. They were able to get their GF's on the phone from the store who went and rented them a canoe and delivered it to us by 2AM.
Actually quite feat because there was no cell phones and we were like 2.5 hour drive from home.
Never did take picture of the beam but the second picture here would be to the right of it.
You're on deck mr1precision