Sail Area & Power Calculator
🔺 Sail Area & Power Calculator
Calculate sail area to displacement ratio and evaluate sailboat performance characteristics.
Understanding Sail Area to Displacement Ratio
What is SA/D Ratio?
The Sail Area to Displacement ratio (SA/D) is like the power-to-weight ratio of a car. It indicates how much sail power is available to move the boat's weight. Higher ratios mean more power and typically better light-wind performance.
SA/D Ratio Categories
- < 14: Underpowered, motorsailer type
- 14-16: Conservative cruiser, heavy weather oriented
- 16-18: Average cruiser, good all-around performance
- 18-20: Performance cruiser, spirited sailing
- 20-22: High performance, requires active sailing
- > 22: Racing oriented, demanding to sail
Choosing the Right Sail Area
Consider your sailing style, typical conditions, and crew experience when evaluating sail area. More isn't always better - overpowered boats can be difficult to handle and require frequent reefing.
Frequently Asked Questions
What SA/D ratio is best for cruising?
For comfortable cruising, an SA/D ratio between 15-18 is ideal. This provides good performance in moderate winds without being overpowered. Boats with ratios of 16-17 offer the best balance of performance and manageability for short-handed crews.
How do I measure my sail area?
For a triangular mainsail: Area = (Luff x Foot) / 2. For a genoa: Area = (Luff x LP) / 2, where LP is the perpendicular distance from luff to clew. Sail makers often provide these measurements, or you can find them in your boat's specifications.