A friend of mine is an archaeologist near Wilmington, NC and I saw a post of his on Facebook today. He and his team found a 250 year old cannon in the Cape Fear! I've attached pics of the FB post and where it was located. Here's the article: Capt. William Dry's brave patriotism helped spur Revolutionary War - News - Wilmington Star News - Wilmington, NC
If you're sailing or boating in the area this is a great place to stop. It's a true learning experience for children and adults, too. When I was looking on the map to see where it was found, I saw that Navionics even has "Ruins of Old Brunswick" on their charts! I put a a blue marker on the chart where the cannon was found so you can see. I've been to the plantation before (by way of land) and it's a really neat place. Definitely worth visiting if you're in the area.