brass spike

Hello All, I found this today while beach combing off the east coast of NC and am wondering if anyone knows what type of spike this is and what was it used for. It appears to be either brass or bronze. Very well preserved and its about 3 inches long. Much appreciation.

I found this item in about a foot of water, low tide, Atlantic Ocean, on the Outer Banks of NC. It was found a couple days ago. Not sure exactly what it is. 29 yrs. of beachcombing, my best find.