J/30 Class Association Forums J/30 Forum Racing Tools and Techniques Vang, main sheet, and traveler

One thing that may help you trimming is to make sure your jib and main are fully "instrumented" with telltales. The main will typically have telltales on the leech. You can augment that by sticking telltales to the main, starting 6 " behind the luff then horizontally aft equally spaced so you have 4 telltales in a row including the leech. Set this up with three rows equally spaced from the top to bottom.

The jib would have telltales a couple inches in from the luff tape (Upper, middle and lower 3rd) , and matching telltales on the leech.

Ideally you want good flow across the main. By adjusting the various line (sheet, outhaul, traveler, vang, halyard... ) you will see the effect of your trim adjustments under various conditions. If you have instruments, record boat speed, wind speed and wind angle. Try and match the profile of the jib and main so if you were behind the boat, looking into the slot everything would be parallel.

What you'll find is there is no single correct trim. It will change with wind speed and chop. Over time as you gain experience you'll see what works better (when to twist off the main, when to twist of the top of the jib to dump air, when to put the traveler down, etc.).

If you have the benefit of someone in a second boat (best if another J/30 but any boat relatively close in performance will work), you can do two boat tuning. Both sail upwind, one keeps everything constant, and the other make adjustments noting differences in relative point and speed.