Mysterious timber

In the estuaries, inlets and sea lochs of Scotland there are many examples of ancient timber sticking out of the littoral mud. 

Where we used to live on Loch Fleet there were the uprights of a demolished pier. It was obvious what they were. The funny story here is how the army were invited to blow it all up, for practice, when it fell out of use. They used so much explosive they had to pay to reroof all the houses on the other side of the loch as the debris fell on them. But the uprights remained.

Elsewhere you might find the ribs of a long disused fishing boat. Or the remains of what was quite obviously a mooring. Or a line of pilings to mark a channel. But you can readily tell tell what you are looking at.

Here, I have no idea.