CLC’s rudder hardware comes with a little L-shaped thing that’s billed as a stop tab.

Idea is it’s secured to transom above upper gudgeon so as to be able to be pivoted clear for shipping rudder yet when rotated back into vertical the tab end keeps pintle from pulling out.

I know I bought one from Land’s End 45 years ago for a stripper scow I built, it worked exactly as intended.

   My skerry instructions were not clear on the rudder stop, so I didn't realize that little L bracket was it.  I found and tried one of the leaf spring rudder stops like you see on Lasers, but it didn't work as well as the L bracket once I realized what it is.

I drilled a hole in the bottom of the top pintle.  A stainless steel split ring through that solves the problem.

Hooper  

   I wrapped some duct tape around one of the pintles.  It adds enough friction between it and the gudgeon to keep the rudder from coming out.  When the tape wears off, I just add some more.  Same method works for the oar pins.