Earlier this year, I discovered that my J/30 rudder was thicker and heavier than the class specification.
Specifically, the width of the rudder foil at the widest section was about 0.5" thicker than originally intended by
J/Boats. "Width" as in the thickness from the port surface of the rudder to the starboard surface measured at its thickest point. Hard to say if it was ever the right thickness or if it had swelled with moisture and age but 0.5" is 0.5".
Its been many years since I calculated the "Reynolds Number" of a foil but suffice to say that there's no place that a foil's measurements should be wrong and wrong at the leading edge is hydrodynamically very bad. It can create the wrong flow of water across the control surface and, in some conditions, cause the foil to become ineffective. Knowing that my old foil was 0.5" fat explains a very heavy helm in heavy air - much more than expected. It was a constant battle with the tiller and the rudder showed a lack of responsiveness. Its easy to determine if your rudder is out of spec, the proper specifications are
at this link. In addition, 0.5" of extra width stretching over 40" or so of rudder creates about 20 sq.inches of surface area to drag below the waterline. This is a significant drag to someone who cares if a line is overboard during a race.
This past Spring, I installed a new rudder made by
Competition Composites and am very happy with the difference that it has made. The key difference is that the new foil stays responsive in all wind conditions. Specifically, in higher winds, there is no sense that the rudder is becoming inefficient and heavy. The Class Spec won't allow a balanced rudder, so you can't achieve the super-light touch available on some tillers, but having one that is correctly designed makes a BIG difference.
The guys that own CCI sail at my Club and I can attest that they understand racing. They were quick and responsive. And the product was ready when promised. And fit right in to the hole that the old one left behind.
The new rudder is substantially better. Worth, in my opinion, the investment. You'd spend as much or more on a new sail and, for the reasons above, I would argue you will get more of a return from your investment on the race course out of the rudder. The J30 rudder is on CCI's website
here I will admit that the new, black carbon-fiber tiller was a total luxury and, I understand, not an option for you OD folks...but it sure looks nice and weighs less that the three bolts that fastened the old tiller to the rudder: almost makes up for the beer and ice in the cooler on the Tuesday night races.
