as far as scale, I thought it might be a cleat to tie lines on a boat...but after magnifying the picture and seeing the size, it DOES look like the upper arms of an anchor. Interesting find, and nicely done!
Got to see the object in person and take measurements. It has a slight curve to it, like a giant boomerang. The whole thing is 45" (3 3/4 ft) tip to tip. The ends are rounded. About 4" wide near the end and 6.5" wide in the middle. The center ridge on the one side is 2" wide and 1"-2" tall (hard to say with the encrusting).
Significantly, I got a new angle that wasn't apparent in the previous photos I was sent and which I assume is the most significant. On the other side of the "flukes" from the rectangular ridge is a part that sticks off - about 4" tall, 2" wide at the base, and 3.5" wide at the widest point. It's rounded, with an apparent slight bulge to one side. Like the shape of a golfball on a very short tee. It looks like it was hollow, but now filled with sediment/encrustation. You can see pretty clearly in the photo.