S/V Constance, Alberg 30 #262 -- Sail Theory

Arvel Gentry PDFs on Sails and Sailing

1. How Sails Really Work -- streamlines, stagnation, and upwash
2. Boundary Layer Flow and the Headsail -- leading edge separation bubble and use of multiple tufts
3. How a Sail Gives Lift -- circulation, lift, angle of attack
4. Another Look at the Slot Effect
5. More on the Slot Effect
6. Why the Safe Leeward Works
7. Why the Safe Leeward Works
8. The Double Head Rig
9. Checking Trim on the Wind
10. Achieving Proper Balance
11. Sailing to Windward
12. Are You at Optimum Trim

How Sails Really Work by James Conger

1. Introduction
2. Jib and Mainsail
   • Bubbling the main creates a reversed sail shape in the bubbled portion. The force vector points abaft the beam!
3. The hull and VMG
   • Leeway Angle ~= K * Heel Angle / Speed^2 therefore, get the boat moving; once approaching hull speed, get the boat flatter.
   • In lower windspeeds, head off to increase speed and minimize leeway.
   • In higher windspeeds, head up to decrease heeling and minimize leeway.