A rolling rule, used as a navigational instrument by sailors of the Kriegsmarine during WWII, in heavy dark wood. It was taken as a token of victory, by my father, a sailor aboard HMS Devonshire, from the German heavy cruiser, the Prinz Eugen, following her surrender in May 1945.
The Prinz Eugen was a ship of her time. Built in the 30's to add to the concentrated force of the Nazi navy, named as a tribute to the Austro-Hungarian maritime tradition.
She survived the war after a variety of engagements, chasing down Allied shipping and battling great ships of the Royal Navy, like the Hood and the Prince of Wales, against whom she fought alongside the Bismark.
This rule, a strikingly simple object, doubtless played its part in the cruiser's predatory activities at war. But at sea she was equipped too with more advanced technology, such as sonar to listen for the enemy.
After the war she had a walk-on role in the development of a new kind of warfare. Commissioned into the US navy she was among the target fleet for A bomb tests on Bikini Atoll in 1946. This sealed her fate. She now lies in the shallow waters of a lagoon off a south-sea reef, still visible to the eye.