There's a concrete ship wrecked just offshore of Cape May Point in NJ. It has been deteriorating for many years and soon nothing will remain above the waterline.

At the southern tip of Virginia’s Eastern Shore there are 9 concrete ships, left over from WWII, that were deliberately sunk in a large arc to form a break-water.

It’s at a state park called Kiptopeke. You can rent kayaks and paddle out to see them up close.

https://www.atlasobscura.com/places/kiptopeke-s-concrete-fle...