Rigging

Pocock Classic Cedar Single Racing Shells
Rigging - Ken Shelton
8/7/23

Kenneth & Beverly Shelton
Jim, I just found this article: Riggingh Your Single Scull, by Filipe Salbany, Merrimac River Rownind Association
He says to be sure to check the pitch of the oarlock face, don't assume that the pin itself is at zero even with the boat properly leveled. Adjust to the actual pitch of the oarlock face. We are also assuming that the sleeve on the shaft gives the blade zero pitch.
About outward pitch:

Step 6: Outward Pitch
Outward or lateral pitch is the tilt of the pin away from the centerline of the hull. The standard 0 to +2 degrees assists the tracking of the blade in the water. You can measure it by placing your pitch meter on the lateral aspect of the pin and measuring. You can also see the effect of lateral pitch in the oarlock. With the pitch meter in place against the back plate of the oarlock, check your reading of degrees at mid-drive, swing the oarlock to the catch position and you should see the sternward pitch increase. Then swing the oarlock to the finish and you should see the degrees diminish to assist the release of the blade. Your readings should look like: catch +6 degrees, mid-drive +5, and finish +4. If you have the inverse relationship, your pins could have negative lateral pitch and require creative shimming to rectify.

Here's how I think about it...if one likes a rearward pitch of 4°, then that is only the case with the oar at 90° to the boat's centerline. If the oar swing is through (improbable) 180°, then the actual pitch with the pin at 0° outboard is zero at the catch (against the side of the pin), 4° at the right angle, and zero at the release. A very low pitch doesn't help the catch, and any positive pitch makes for a less-clean release. So, if the actual oar swing is, say 90°, then the actual pitch is +2° at the catch, +4° at right angle, and +2° at the release. The +2° at both ends is no help at all.
If the outboard pitch is 2°, rearward pitch +4°, then the catch will be +3°, right angle still +4°, and the release +1° with our 90° oar swing giving better bite at the catch and cleaner release. Greater oar swing improves things even more. If one has greater oar swing then 1° outboard will be OK. If one has less swing of the stroke then 2° outboard might be worth a trial.
Ken