Twist is minimized when what condition is met?

• A. Top battens parallel with the boom
• B. Top battens perpendicular to the boom
• C. Halyard tension max
• D. Mainsheet fully eased

Answer: (A)

Twist is how much the sail’s angle of attack changes from bottom to top under wind load. The top battens shape the upper part of the sail, and where they run relative to the boom changes how the top edge behaves when you’ve got wind pressure on it. When the top battens are parallel with the boom, the upper portion of the sail stays more in line with the lower portion, keeping the upper edge from rotating in as much. That keeps the angle of attack more uniform along the sail and minimizes twist.

If the top battens are perpendicular to the boom, the upper section is forced into a shape that tends to twist more as wind loads shift, so the sail twists more rather than less. The other options don’t directly control how the sail twists along its height: maximizing halyard tension changes luff tension and sail height, which isn’t the primary lever for twist distribution, and easing the mainsheet lets the boom spread out and generally increases twist rather than reducing it.