Duncan,
A slight error with the URL, it should read :
http://www.telegraph.co.uk/history/1005 ... sters.html (only half the code was coming out on the link)
I used to work at the lab where they tested the original theories (the bit where the ball is 'skipped' along the ship tank) , and worked along side a chep who was there during the filming. To be technically accurate, when the film was made they actually filmed in the wrong tank - there were two, one running North- South and one running East-West; the original work was done in the North-South tank, but they filmed in the East-West as it made for fewer lighting problems.
One little story, it appears that the senior props man for the film approached the lab and asked if there were any existing plans for the Barnes Wallace catapault, so they could build one for the film, "Oh no"came the reply, then, after a short pause, "...Do want to borrow the original?" - so, in the film, the tank is
nearly there, but the catapault is spot on.
The buildings around the tanks were pulled down in about 1993 and, when I last saw them, what was left of the tanks were filled with rubble & earth (I would suggest thet it was for a raised garden, but I suspect it's just a conenient place to dump excess rubble & earth.