IIRC the navy/airforce used the Loch for practice/testing during WW2 so my first instinct was that it was something to do with that. However, it looks too new to have been down for 60 years and those things on the end that appear to be light covers (?), where they in use then ?
I would say it looks like a single pontoon from some sort of floating platform. beyond that.. Sorry, no idea! :embarassed: