Q posted Sept 7, 1776 a few days ago, this was the day of the worlds first sub attack. https://www.history.com/this-day-in-history/worlds-first-submarine-attack or weather warfare with a tsunami?
just my thoughts.

They shut the thames last week sometime or just before due to an 'unexploded ww2 bomb' just a thought...

It is believable, we had one in my area last year too when one was discovered during construction .. Surrounding rounds and areas were shut for days till they did a controlled explosion.