I do like to have a wingnut on my pivot bolt if I can but that can only be fitted to a metal stock easily,wood needs a bit more work.
As been said,do you want to hold rudder up only ashore or for other reasons?
One problem with a wooden stock is that the insides of the stock doesn’t get enough varnish and swells with the dampness.
Sand the insides,varnish well and when hard lightly sand the nibs off to make smooth.
Then if the blade is a loose fit,make some shims or washers out of say,formica or some such stuff(Good Word Colin !) to pack out the blade to the average thickness of the stock.
The bolt can then be tightened so that the blade can be pulled down but will hold up out of the water when needed.
Use a bolt with a Nyloc nut on stainless steel bolt.
I like to also fit a two to one on the downhaul rope but try not to use the very best rope.
I ones caught an underwater mooring line with the rudder going very fast down wind and with the spinnaker up!
The boat stopped very fast,swung about a bit but thankgoodness the lighter downhaul broke and the rudder came up before we fell over. 😯
So the downhaul is sacrificial on my boat now and I still have the wing nut.
Sorry Liam if you have heard that story before!!!
C P 🙂