Day 14.255: What is that?

This strange metal object protrudes from the beach (Western Beach in Scarborough Maine to be exact) near where we took the selfie at the beginning of our circuit of Prouts Neck:

Exile #2 thinks it may be in some way related to the addition of sand here (dredged from a nearby river) by the US Army Corps of Engineers in 2004. She may be right, but I've found no convincing evidence one way or the other. It's quite a striking landmark anyway (since scale is hard to tell from the photo, I'd guess it's about 8 feet from sand to top).