Home Page Hull Speed Capsize Formula Stability Angle SA / D Ratio D / L Ratio Sail Wind Load Swinging Radius STD Calculator Motion Comfort Calculate Speed Current Deviation Course To Steer Landfall Fix True & Apprnt Wind

SA/D Ratio is the sail area/displacement ratio.  This ratio indicates how fast the boat is in light wind.   The higher the number the faster the boat. 

* Cruising Boats have ratios between 10 and 15.
* Cruiser-Racers have ratios between 16-20.
* Racers have ratios above 20.
High-Performance Racers have ratios above 24.

SA / D  = Sail Area / (Displacement in Cubic Feet )2/3

   Enter the Sail Area in Square Feet:   
2.  Enter Displacement (Boat's Weight) in Pounds:
- OR -
Enter Displacement (Boat's Weight) in Long Tons:
Enter the Displacement in Cubic Feet:


  Reference:  Rousmaniere, J,  The Annapolis Book of Seamanship  Simon & Schuster, New York, New York,  Chapter 1:  The boat p26-35, 1999.

Copyright 2001            Website last updated 05/11/2005