The Mary Rose sank in 1545, taking 500 sailors with her. The wreck ofthe ship was raised in 1971 and since then, archaeologists and scientists have been trying to find out why the flagship of Henry Vlll 's royal fleet sank. Quentin Cooper talks to two scientists who have been studying the tree rings in the ship's timbers in an effort to discover the reasons forthe vessel's mysterious sinking. Producer John Watkins. E-MAIL: material.world@bbc.co.uk Quentin Cooper 's webwatch: page 43