Lower rudder gudgeon
Check your lower rudder gudgeon while motoring at full power. To do this, you need to crawl headfirst into the quaterberth, remove the inspection panel under the aft center of the cockpit, and stick your head in there with a flashlight. Look for a trickle of water flowing forward in the skeg from the lower gudgeon. If that's your problem, rebed/replace the gudgeon, and check the upper one while you're at it. The attachment screws may be threaded into tapped holes in brass plates buried in the fiberglass laminate of the transom.On my 1979 C-25, I ordered the upgrade gudgeons & pintles from Catalina Yachts, drilled out the original 1/4" holes in the gudgeons and transom for stronger 5/16" bolts, and added 3/16" thick fiberglass and epoxy backing plates. To get at the hidden side of the upper gudgeon installation, you'll need to install a 4" Beckson plate in the aft wall of the cockpit.Good luck.-- Leon Sisson