This listing features a Weems & Plath Nautical Slide Rule, a classic tool used for marine navigation, specifically designed to calculate time, speed, and distance at sea. Ideal for sailors, navigators, and collectors of nautical instruments, this slide rule offers a practical solution for common maritime calculations. Model: Weems & Plath Nautical Slide Rule Function: Time-Speed-Distance calculations for marine navigation Material: Durable plastic/paper construction, waterproof Dimensions: Approximately 7.5 inches square Condition: Used, with visible yellowing and signs of wear consistent with age and use; remains fully functional Features: Provides immediate solutions to all common speed/time/distance problems Converts between nautical and statute miles Computes distance in yards when speed is factored in knots Speed in knots or MPH; time in hours, minutes, or seconds Distance in nautical or statute miles (or yards if desired, and if speed is in knots) Easy to read and accurate Standard in U.S. Navy A practical and collectible nautical calculator, perfect for maritime enthusiasts, naval history collectors, or anyone interested in traditional navigation tools.