Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
Use a Q-tip or something to get some of the polyurethane into the holes. They're often the source of rot and delamination. You can also chamfer the holes in the wood with a larger bit so some sealant can hold to the bolts without being squeezed out as you assemble the whole thing, preventing water migration on the bolts. Water is diabolical...
Having had my old tiller snap off in my hands, when I made a new one, I over drilled all the holes, and filled them with epoxy. Once set, I drilled inner holes for the bolts, tiller pin, etc. Water will never get into the tiller through those holes. I also did three coats of epoxy over the entire tiller, and bedded the tiller cap with thickened epoxy as well.
As Dave said, water's diabolical, I'd add insidious and relentless.
i changed my rudder and i had to notch my tiller exactly like your's (i also shortened it by 2" at this end, and drilling the 3rd hole further up, ended up nice)
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.