Within about 3 days, this "explanation" has been posted on over 4,000 websites:
The weapon was built with wire mesh which could have baffled submarine radar, leading enemy craft to crash - much in the same way as turning out a lighthouse could be used as a weapon against shipping.
But now former Swedish naval officer and WWII expert Anders Autellus has revealed that the structure - measuring 200ft by 25ft - could be the base of a device designed to block British and Russian submarine movements in the area.
The huge steel-and-concrete structure could be one of the most important historical finds in years.
Autellus claims it would have been built of double-skinned concrete and reinforced with wire mesh to baffle radar - which could explain why the dive team's equipment repeatedly failed near the mystery object.
Given that submarines can't use radar under water, and that wire mesh doesn't "baffle" radar (or sonar), nor does it cause electronic devices to fail (fortunately, since it's used extensively in concrete slabs), and that there doesn't seem to be any reference anywhere else on the web to any such anti-submarine device, I'd have to say that "sunken UFO" is more plausible, since we don't know whether or not they exist. The only interesting thing about this theory is how fast and far it has spread simply because Anders Autellus is referred to as an "expert." As nearly as I can tell, Autellus must be referring to anti-submarine nets, which were intended to trap submarines rather than "baffle" their radar. Those did use concrete anchors, but this thing (200 ft) is implausibly large for that purpose.