J24 Rudder Question

Thread starter #1
Racing with hull 3364 (1983) and wondering if the rudder original to the boat will be the updated fairing shape that one would see on a new rudder? / Is the shape substantially different that it would have a noticeable effect at a regional competitive level? Would be nice to know before dropping down the $ for rudder templates.
I'd recommend starting with a big caliper to see how much thicker than the class minimum chord thickness you're at right now. Historically speaking there's good advice against trying to "thin" out an older factory original rudder blade, because you risk weakening the laminate and encouraging a failure. That said, if you're close, say +4mm or so, and the trailing edge and leading edge don't show evidence of splitting (sign of water intrusion), your efforts are better placed elsewhere.

The rudder thickness on a J24 isn't as meaningful as say a fair, smooth, and symmetrical rudder shape, and even that is less important than a fair, smooth, symmetrical, and as far forward as possible keel shape. If you can't say for certain that your keel is really dialed in, I'd hold off on the rudder work.

That said if your rudder is approaching +10mm over the minimum thickness, and shows signs of splitting along the leading and trailing edges, I'd recommend shopping for a new rudder blank, rather that attempting to fair. Build up the new blank with new hardware and make both rudders fit your transom hardware. Now you have a spare.