torpedo. still upright, draped in the algae of 70 years under water. a glimpse inside. shiny containers. cargo of tea. the real prize hidden from view. silver worth an estimated $148 million pounds. we re extremely excite add about this find. it is massive for us in so many different ways. the deepest ever. it s potentially the richest ever. and technology, challenges that we have ahead of us are something we can sink our teeth into. reporter: a rare picture of the ship. receiving its cargo will be difficult but clearly worth it. the ship s last journey is well documented, left calcutta, to join a convoy from liverpool. miles off galloway it was torpedoed. it laid at the depth of nearly