The Sabre Daggerboard (Patent Pending)

The standard Sunfish daggerboard is a good design for its vintage, especially considering the severe limitation of making it fit in a narrow trunk. Its vertical leading edge is prone to collecting weeds. The planform results in less than optimal lift (side force) distribution. The fiberglass construction is strong and smooth, but also brittle. It was a major improvement though over earlier boards!

Combining the most advanced flow prediction methods with 40 years of experience in wing design, AeroSouth has developed a new daggerboard that reduces drag and improves maneuvering. The board's hydrofoils and planform have been custom-designed for sailing craft at typical speeds. Nearly a hundred variants were studied before our final Sabre design was selected.

CL/CD (ratio of lift to drag) versus angle of attack for the new AeroSouth dagger board (red) and the standard Sunfish board (blue). Our new design has a 25% higher maximum CL/CD, meaning lower drag for the same side force. Drag is lowered by up to 40% at higher angles of attack. The smooth, curved leading results in softer 'stall' at higher angles of attack, reducing deceleration during maneuvers. It is less likely to collect weeds than the vertical leading edge of the standard daggerboard.

New AeroSouth Sabre daggerboard (top) compared to the legacy fiberglass board. The Sabre has numerous advantages, including:

• Very affordable
• Lower drag = higher speeds
• 15% lighter
• Smooth handgrip in head
• Robust, attractive materials
• Better weed shedding
• Quick delivery
• Engineered & Made in the USA

Modern stress analysis has shown a comfortable strength margin for a 100Kg (220) side load, as might occur when righting a capsized boat. Two large 25mm (1") diameter holes for attaching lines and a slot to aid in lifting are designed into the head. 

Conversion from the older board to the Sabre takes only a few minutes: Install the rubber stop in the pre-drilled hole, attach your line and you are ready to go. The new AeroSouth daggerboard is guaranteed to improve your speed in all conditions. Made with the same laminated sapele wood as pioneered for our revolutionary FS rudder blades, the Sabre beats the competition in many ways, and it looks great, too! Get yours now and be the envy of your Sunfish fleet.

Noted east coast Sunfish sailor Alex Dean tests the first AeroSouth Sabre daggerboard during a regatta hosted by the Blackbeard Sailing Club, New Bern, NC on 11/14/20.

Figure 168 in the classic reference for sailboat design, 'Sailing Theory and Practice' by C.A.Marchaj, shows what a difference of only one degree lower drift angle makes - 106 feet when sailing close-hauled over a course of only one mile length. Drift angle is directly related to the ratio of lift to drag for the daggerboard and rudder. Marchaj further states: "Over a typical triangular regatta course 10 miles long, some half of it the windward leg, the gap between the two yachts will be over 500 feet."