nautical navigation PARELLEL

Description

Vintage Capt Field's Improved nautical navigation parallel made of box wood or beach! with brass fittings, has all the measurement marks in good condition ,no chipping or cracks in wood ,has a ink name of owner under brass swing arm (removable) made by Aston and Mander? works well.  12 in.
These things dont change much  , my calculated guess is its pre 70 s belonged to my father.