ɐ bɹˈɛtən plˈɑːɾɚ fɹˈɛntʃ:, ˈɔːlsoʊ nˈoʊn æz ɐ pˈoːɹtlənd kˈoːɹs plˈɑːɾɚ ɔːɹ wˈiːmz pɹətɹˈæktɚ nˈeɪmd ˈæftɚ lˈeɪɾɚ mˌænjuːfˈæktʃɚɹɚz pɹədˈuːsɪŋ sˈɪmɪlɚ dɪvˈaɪsᵻz, ɪz ɐ nˌævɪɡˈeɪʃənəl ˈɪnstɹəmənt jˈuːzd fɔːɹ nˈɔːɾɪkəl nˌævɪɡˈeɪʃən wɪð tʃˈɑːɹts.
A Breton plotter (French: ), also known as a Portland course plotter or Weems protractor named after later manufacturers producing similar devices, is a navigational instrument used for nautical navigation with charts.