Toleta de marteloio (course-solving table)
Toleta de marteloio (tabla de resolución de rumbos)
- Date
- siglos XIV-XV · confidence low
- Place
- Venice, Veneto, Italy
- Credited to
- Venetian and Mediterranean pilots
- Field
- Movement
What it is
A table giving, for each oblique course and distance sailed, how far one has advanced along the desired direction and how far one has drifted. It allowed dead reckoning and course correction on a portolan chart without trigonometry.
The main sources are 15th-century manuscripts (Michael of Rhodes, 1434, and the 'Raxon de' marinari'); the technique may be older.
What it led to
- dead-reckoning navigation with chart and compass
- correction of oblique courses without trigonometry
- a basis for rhumb-line methods and Atlantic routing