This page is editorial context and commentary about an unpublished essay by Jef Raskin, not the essay itself. Jef Raskin (1943-2005) was an American human-computer interaction expert and the originator of the Apple Macintosh project; his estate retains all rights to his published and unpublished writings.

This unpublished piece explored the design and physics of rigid sails — solid wing-like structures used in place of traditional fabric sails on watercraft.

Rigid Sails and Aerodynamics

Unlike conventional soft sails that rely on fabric tension and wind pressure to form their shape, rigid sails maintain a fixed aerodynamic profile similar to an airplane wing. This allows for more precise control of lift and drag, and in many conditions, significantly better performance than cloth sails.

Raskin’s Approach

Raskin brought his understanding of aerodynamics — developed through his work on the Coanda effect and airfoil design — to the analysis of rigid sail configurations. He examined how the principles governing airplane wings apply to vertical surfaces propelling boats through water, and what design tradeoffs are involved in choosing rigid over flexible sail structures.

Engineering Considerations

The essay addressed practical challenges of rigid sail design, including structural weight, storage and reefing (reducing sail area in heavy wind), and the mechanisms needed to control a rigid airfoil on a moving platform. Raskin’s treatment balanced theoretical analysis with attention to real-world constraints.

A Convergence of Interests

Hard sails sat at the intersection of several of Raskin’s passions: aerodynamics, engineering, and the outdoors. The essay reflects his habit of applying rigorous analytical thinking to subjects that most people approach purely through tradition and intuition.

This page is part of the Jef Raskin Reference, providing editorial commentary on the unpublished works of the creator of the Macintosh project.