While serving aboard her , Choules witnessed the surrender of the German Imperial Navy at the Firth of Forth in 1918 , ten days after the Armistice , and was also to witness the scuttling of the German fleet in Scapa Flow . While serving aboard it , Choules witnessed the surrender of the German Imperial Navy at the Firth of Forth in 1918 , ten days after the Armistice , and also witnessed the scuttling of the German fleet in Scapa Flow .