Learn the fundamentals of sail theory and the nuances of upwind sail trim

4 Hours English Unlimited Access Trim Simulator

Sailing efficiently upwind - against the force that drives us - is a marvel of modern design. This online course provides a fundamental understanding of the forces behind upwind sailing as well plus advanced techniques that balance the angle of attack, sail depth, and the twist of your main and jib in order to optimize speed and pointing in all conditions.


Bicycles, bobsleds, sailboats - no matter what you race, you’ve got to be fast to win. If it’s sailboats you race or cruise, then this online course is for you. You'll learn the latest in sailing skills with an emphasis on practical, proven, real-world techniques that will help you sail faster. Even if you never race you’ll learn how to sail with better speed, balance, and control.

Sail Theory

If you've ever wondered how sails work then this online course will explain the basics.

Angle of Attack, Depth, Twist

Learn how the angle of attack, depth, and twist combine to control upwind power.

Sail Controls

It's time to take the theory and put it into practice as we discuss how to use the controls on your boat to change the shape of your sails. The interactive Sail Trim Simulator allows you to see how changes in sail controls change sail shape and performance, while video clips show real-life trim and performance techniques.

Upwind Trim in All Conditions

An in-depth look at how you can set up your boat and trim your sails upwind in a variety of different conditions. Including a special Trim Solutions section to solve the most baffling problems in upwind performance.


The North U Trim Book covers every facet of sail trim, boat speed, and boat handling. You’ll learn how to trim and shape control performance – upwind and downwind, for both symmetric and asymmetric spinnakers. Special sections on Trim Solutions solve the most baffling problems in performance. Please note, the textbook is not included in the online course, but it is recommended - order your North U Trim Book online today.


Bill Gladstone is the director of education at North U and author of the North U Trim, North U Tactics, and North U Cruising books. Bill has been teaching sailing for over 40 years. Graduates of his courses are sailing with confidence and winning races the world over.