The HMS Orion at Suez in 1943.
My mum (Janet Ryan) recently wrote this about grandad (Arthur Mulligan) and his connection to the ship…
"…During the war he was called up to join the Royal Navy. My father was soon promoted to Lieutenant Instructor, and on HMS Orion he served in the Mediterranean where his maths and astronomy were invaluable as he was called on when enemy mines were spotted as he could easily calculate the distance speed and direction which the warship Orion must navigate to avoid the mines: I understand from an aunt that he had little sleep during this time. He was also at Scapa Flow ( Orkney ), fortunately not when the U boat entered unseen. He taught navigation at Greenwich and at Portsmouth".
I remember being told about this by mum once, I must have been young because the explanation I got, was that his job was to drive ships at night using the stars instead of a map.