Sand Formed Around Sailboat Hull
I think this sailboat has been on the beach for a while - the sand has been formed by waves washing around the boat. I suspect the keel is buried into the sand. The hatch on the front deck appears to be broken.
Barge With A Tree
The barge helped to amplify the small waves so the kids were concentrating there to get a bigger ride. I wonder how long that barge has been there.