I know the one very well. I have family in Brewster and we used to see it all summer. Even fished around it quite a bit.
A little backstory: It's the
SS James Longstreet it was sunk (intentionally... after running aground, being declared a total loss and being towed to that location) and used for bombing practice until the early 1970s by the USN and USAF.
After bombing stopped, it sort of just sat there and rotted away. I remember being a kid and seeing it from Brewster at the right tides. Up close it was an eerie ruin (saw it by boat a few times). Today, it's no longer visible from shore regardless of the tide.
According to this article, it vanished sometime in the late 90s which would make sense because I have little recollection of seeing it after about that time (I would have been in my preteens or early teens between 1996-99). I don't think you can walk to it, although I could be wrong. You may be able to walk close at low tide, but I don't think you can get right to the wreck. In fact, the wreck was off limits to boaters and divers for a long time, but that's no longer the case (even though many charts and materials still say that it is). Here's a
great resource with lots of photos, including photos from a dive on the wreck.