Learn more about sail trim with either NauticEd’s FREE Basic Sail Trim Course for any aspiring sailor, or learn more comprehensive techniques with the Advanced Sail Trim online course.

Get Basic Sail Trim for Free > Advanced Sail Trim Course >
Coastal Navigation iPad eLearning App

How to use a Breton (Portland) Plotter

/by

Using a Breton Plotter aka Portland Plotter (aka rotating protractor) to determine a course

They say a picture is worth a thousand words – we say an animation is worth infinity! Check this out.

Here is an animation of how to use the Breton Plotter to determine a course. We use the Long Island Sound chart to determine a course from a buoy we are passing close to – to the entrance buoy to New London Harbor. We want to know the true and magnetic course. Note this is not equivalent to your heading. Heading will take into account the leeway and current. We cover how to determine your heading using the known course in our Coastal Navigation course.

Have fun with this animation and please share with your friends.

We have found that this animation is best experienced with Google Chrome.

Buy a Breton Plotter

Learn how to navigate like the pros with the NauticEd Coastal Navigation Course.

Coastal Navigation Course

Coastal Navigation Course

 

Author

  • Grant Headifen

    My vision for NauticEd is to ensure that families and friends get out on the water not only safely but with true COMPETENCE, confidently savoring every moment of their valuable time.

    Achieving this means being the pinnacle of sailing and boating education—offering comprehensive multi-media theoretical instruction coupled with hands-on, on-the-water training through our global network of American National Standards Instructors. We steadfastly avoid becoming a mere certification mill; our focus is on delivering genuine competence, ensuring our students are well-prepared for enjoyable, real-world boating experiences.

    View all posts
Search for a topic.
You might also like
The zero degree Meridian Line in GreenwichHow to dock a sailboat
NauticEd and MarineVerse launch the World's First virtual reality Navigation Rules CourseNauticEd and MarineVerse Launch World’s First Virtual Reality Navigation Rules Course
The zero degree Meridian Line in GreenwichNauticEd talks to hot new sailing app savvy navvy
Maneuvering a Sailboat out of a tight slip exampleManeuvering a Sailboat out of a Tight Slip
Serene sailing boats at sunset with 'How to Take a Sailing Vacation - The Basics' text overlay on calm sea.Bareboat Charter Guide: How to Charter a Sailboat on a Sailing Vacation
The zero degree Meridian Line in GreenwichLongitude Mystery
You are here: Home / Sailing Education / Coastal Navigation / How to use a Breton (Portland) Plotter
Last updated on June 29th, 2025
International Navigation Rules of Preventing Collision at SeaE-book cover on a tablet displaying Catamaran Sailing with NauticEd logo and a sailing catamaran in the background.Maneuvering a Catamaran Advice