The AeroSouth FS Rudder Blade (Patent Pending)

The FS rudder blade is made from a laminate of naturally rot-resistant sapele wood and carbon fiber. Blades are protected with a high-performance, two-part epoxy coating for the ultimate in UV, scratch and water resistance. They are  pre-drilled to fit the standard rudder cheek assembly, making the upgrade from the legacy blade simple. The smaller surface area, thinner hydrofoils and use of wood plus carbon fiber result in a strong but light blade that results in noticeably improved sailing performance. 

Combining the most advanced flow prediction methods with 40 years of experience in wing design, AeroSouth has developed a new rudder that significantly reduces drag. The board's hydrofoils and planform have been custom-designed for sailing craft at typical speeds. A unique aspect is the small, thin chord where the fin pierces the water's "free surface", lowering free-surface drag and moving the center of side force away from the water surface to reduce losses. The elimination of sweep and distribution of area fore and aft of the rudder's axis of rotation reduces weather helm to a minimum.

L/D (ratio of side force to drag) versus angle of leeway for the new AeroSouth FS rudder (red) and the legacy Sunfish rudder design (blue). The FS rudder has a 100% higher maximum L/D, meaning half the drag at the same side force. Low sweep and a modern, laminar hydrofoil shape result in low weather helm and better performance when maneuvering.

AeroSouth's FS rudder has been inspired by the important work of famed Dutch scientist Joop Slooff, whose hydrodynamics research played a critical role in the inverse taper / winged keel of the 1983 America's Cup winner, Australia II. (Slooff and the owner of AeroSouth, Kent Misegades, attended the same graduate school, the Von Karman Institute of Fluid Dynamics in Brussels, Belgium.)

The standard Sunfish rudder is a simple design with high sweep and a relatively flat cross-section. It creates more drag than the standard daggerboard despite having 40% less area. With the daggerboard retracted, it produces most of the underwater parasite drag. Its high sweep reduces maximum side force while increasing weather helm and drag. Of fiberglass construction, it is heavy and brittle, making it vulnerable to damage and difficult to repair.

The FS rudder blade is made from a laminate of Sapele wood, a widely-available species of mahogany. Strength is maintained through the strategic use of CFRP (Carbon Fiber Reinforced Plastic) elements supplied to AeroSouth by Rock West Composites of West Jordan, Utah.. Surfaces are accurately shaped using modern CNC milling equipment and then sealed with epoxy coatings for near-impervious protection from water and UV radiation.  We partner with Prestige Millwork of Star, North Carolina, an outstanding company specializing in precision woodwork for a number of markets.

Smooth contours optimized for low drag combined with a smooth finished surface are the key to improved performance of the FS rudder blade.  The unique, narrow chord (width) of the FS rudder blade at its upper end lowers the normal performance losses where a rudder blade penetrates the water surface.  AeroSouth has developed a proprietary method to laminate long carbon fiber strands (rovings) into the wood to achieve remarkable strength but keep the blade light. 

AeroSouth founder and president Kent Misegades (160 lbs/73kg) demonstrates the remarkable strength of the FS rudder blade. Don't sail a Sunfish? Let us design a rudder blade, dagger board or center board for your sailboat using our advanced "FS" methods.  Contact us here.

• Half the drag - improves speed
• Lower weather helm on tiller
• Rot-resistant Sapele wood combined with carbon fiber
• Repairs are simpler on wood
• Advanced surface protection
• Strong, more durable, yet lighter
• Attractive shape and finish
• Fits existing rudder hardware
• Pop-Up feature retained
• Low cost and quick delivery
• Designed and made in the USA

Well-known Long Island Sunfish competitor and blogger Lee Montes has posted this video on his first impressions of the AeroSouth FS Rudder blade.  On his first experiences with it in the water (12/2020), he reports: "I was actually able to sail both rudders yesterday in steadier  conditions. I started with the AeroSouth rudder and when I went back to the regular rudder I race with it was abundantly clear how much drag and weather helm is on the traditional rudder."  Thanks, Lee!

Long Island Sunfish icon Lee Montes has posted this video on his first impressions of the AeroSouth FS Rudder blade under sail.  "There's no drag, zero weather helm, I'm steering with one finger. It's a nice, balanced rudder. I'll probably sail a lot longer with this rudder, using the same energy." Thanks, Lee!

"The boat feels fast and smooth with the new rudder. The helm is very light, and you don't have to fight with any weather helm. It was a real joy to sail!" Alex Dean  "I had the pleasure of trying out the rudder blade a few weeks ago.  I was surprised by the ease of steering through the waves going upwind. There was very little stress in the wrist or forearm." John Butine  Picture above: ISCA 2019 Southeast Regional winners. From left, John Rhodes (top youth), Sonya Dean (5th), Alex Dean (3rd), Paul Dierze (2nd) and John Butine (1st).