Blade dimension: 16" long by 10" fore and aft at top Shaft 2-3/8" aft to CL of shaft

Shape: Nacra catamaran shape

Positives: Rudder performed very well, very responsive, positive feel. Boat reacted quickly to helm change

Negatives: Rudders seamed too long-windward rudder was always dragging in the water. Leading edge too vertical- water tended to shoot up leading edge-weeds stuck too easily. Rudder was too fat due to prototype mold used. Shaft could be slightly further forward in blade. Slight tendency for rudder to catch on front side. Helm was too neutral.

Blade dimension: 14" long X 9-3/16" wide Shaft 2-1/4" aft to CL of shaft

Shape: Nacra

Positives:

Negatives: This rudder was too small, noticeable less control than #1. It was out of the water, or had less blade in the water on the windward side most of the time, but it was just too small.

Not thrilled with the way catamaran rudder looks

Blade dimension: 15" long X 12" Shaft 2.5" aft to CL

Shape: A-Scow scaled down

Positives: This rudder is aesthetically better than the Nacra. It has a more slanted aft leading edge which helps get rid of the weeds. Also, since there is so much more blade behind the shaft it tracts really well.

Negatives: It had a very heavy dead helm. Unacceptable

Blade dimension: 15" X 12" Shaft moved aft to 2-3/4"

Shape: A-Scow

Positives:

Negatives: Moved shaft aft in the blade to achieve more balanced feel in helm. Did not work!

Blade dimension: Took #4 and cut off " along trailing edge to try and get a more lively helm.

Shape: A-Scow

Positives:

Negatives: Little to no improvement.

Blade dimension: 15" X 9-7/8" Shaft @ 2-3/8"

Shape: Nacra with modified bottom to resemble A-Scow.

Comments: Back to catamaran shape to get the lively feel back. Put blade in foil at an angle to increase the leading edge slant for weeds and water shedding, and give the rudder a bit more helm. It achieved all of the above, but maybe too much helm. We still donŐt like the way the rudder looks. The rounded bottom goes through the water very nicely, but perhaps it gives up too much area at the bottom of the rudder.

Blade dimension: : 15"X 9-7/8" Shaft @ 2-3/8"

Shape: Nacra with modified bottom to resemble A-Scow.

Comments: This rudder was built with slightly less slant in the leading edge than the last one to re-balance the helm slightly. It will have a modified bottom that will look like the bottom of the A scow blade to improve effective area, improve aesthetics and improve control.

This rudder was really good, but maybe a bit short now that we have the shape where we want it.

Blade dimension: : 15-3/4" X 9-7/8" Shaft 2-3/8"

Shape: Nacra & A-Scow (Same as #7)

Comments: Slightly longer blade to get more area and control. Rudder performed very well in all aspects.

Blade dimension:

Shape: Nacra & A-Scow
Same as #8 but with a straighter exit and squared off trailing edge.

Comments: This rudder seamed very good, slight vibration due to trailing edge.

Blade dimension:

Shape: Nacra & A-Scow (This rudder was the same as #9 but with a thin slanted trailing edge)

Comments: Vibration was worse. Possibly due to the density of construction.

Blade dimension:

Shape: Nacra & A-Scow (Same as #9) Back to square trailing edge for durability and a reduction in the vibration.

Comments: This rudder was built out of 20lb. Density, 2-part foam. Foam gassed off too much under gelcoat and caused blistering problem.

Blade dimension:

Shape: Nacra & A-Scow (Same as #9)

Comments: Shape is very good now, just need to dial in construction and trailing edge. This blade was constructed with epoxy and phenalic beads. This construction was too porous and not strong enough.

Blade dimension:

Shape: Nacra & A-Scow (Same as #9)

Comments: This blade was built with epoxy, and a mixture of mill fibers, micro balloons and phenalic beads. This rudder was slightly heavier, but a stronger more dense mixture, which reduces porosity on the blade and vibration or singing of the rudder.

I shipped this blade to R/P Yacht Design so that they could put the blade profile on the computer and generate a computer shape to the correct naca shape. I then constructed a rudder mold with these templates and these are the rudders we have today.

Blade dimension:

Shape: Nacra & A-Scow (Same as #9) with Molded NACA shape.

Comments: Built out of the new computer designed mold shape, two rudders for the ILYA championship for Bob Biwer. Rudders proved to be very good. Bob showed very good boat speed, which was encouraging. There was some concern that the rudders would be slower due to the thickness of the blade compared to the plate rudders. Our efforts to keep the rudders thin have paid off and no apparent speed problems are evident.

Bob went on to win the Nationals with these rudders in very big waves and high winds. The ultimate test for the rudders. Bob also won the E Blue Chip in predominantly light winds so they have now been speed tested in a big variety of winds with no negative feed back.

Conclusion:

The new foil rudders will not only dramatically improve boat handling, but they will bring the boat into the current realm of technology. Aesthetically, the rudders look better, they are less expensive to produce and they will not crack around the shaft. There is no question that these rudders will level the playing field. There is less demand on sail trimmers to drive the boat and more on the guy with the stick in his hand. This will bring the entire fleet closer together.

A huge step forward in making the boat easier to sail!