Check this out. This was a homebuilt submarine, some guy in Brooklyn built back in the 70's. I remember my old man taking me to see it when I was a kid. It was painted yellow and was kept at a local marina. He built it to go and dive on the Andrea Doria. But wasn't too successful with with it. Apparently he made a few dives with it near the Verazzano Bridge.
Now it sit in Coney Island creek in Brooklyn. Ive been out to it a bunch of times over the years. I was on it last yr. Took a ride out to it in my kayak. Always wanted to take a peek inside it with my scuba gear , but that water is vile.
