Don’t work too hard on how a stationary pipe on the sea floor might get itself “holed.” Within the first few hundred feet, especially, finding it is quite easy. A good fish finder could do it. We’ve had pipe crawling robots, both outside and inside, at least since the days of the Alaska pipeline. They’re not large and could be dropped from a “fishing boat.” Remember how the IRA got Lord Mountbatten? A pipe crawler could easily drop a magnetic limpet mine and be contact or remotely detonated. And a crawler might not even be needed depending on what’s available for a mine. A 50 pound case of dynamite would/could destroy a five foot diameter piece of concrete coated pipe so the carrying capacity of the robot need not be dramatic. Estimates of large bunches of explosives being used are just exciteable folks reading too many comic books.
Very interesting.
The explosive force is multiplied by hydraulic water pressure.
Recall the story of Barns Wallis and his bouncing bomb that blew holes in the Ruhr dams.
Bouncing bombs allowed Wallis to completely avoid the torpedo nets protecting the dam. However, to get the bounce just right, the Lancaster bombers needed to approach the dams flying just 20m above the water while traveling at 230mph.
At exactly 389 metres from the dam wall – calculated by triangulating with the dam’s towers – the bombs were released. Wallis calculated that backspin would stabilise the bombs in ‘flight’, help create the bounce and forced the bomb to cling to the face of the dam once it sank.