If the blade is attached using threaded drifts, you may need to use similar construction to the original. That was the way many yacht rudders were built until all-glass rudder become common. The annual shrinking and swelling of a rudder built that way takes its toll, however.
The rudder built...
It might be worth taking a profile template off now, so a new blade could be built at your leisure. Of course, I might take the opportunity to change that traditional profile to a slightly more modern Constellation-type rudder profile, with more area at the bottom.
What is the boat? An old Pearson?
I'm a bit confused by your process. I was taught to do this much like a scarf in wood. You start out with a small circle of glass, with each successive layer slightly larger in diameter, so that the final one is essentially the full size of your ground-out area.
Camden has a pump-out boat which we have used regularly. Northeast Harbor has a busy dockside pumpout station, but it is in an awkward location and shares dock space with several ferries, so it's not always easy to get to. Fortunately, the no-discharge zone ends about a 15-minute run from our...
This is the irony in a lot of US bays that have major cities, which means almost all of them.
The worst situation we got into was when we left the boat in a marina in Gibraltar for about six weeks while we went to England to do the AC Jubilee Regatta and for work prior to a Volvo/Whitbread...
I don't pretend there aren't a lot of things that can go wrong with a conventional head. I've experienced most of them over the years.
At the same time, it's hard to beat the convenience of what I have now, with a Vacuflush system.
I will have replaced most parts of it by this summer, however...
Mate, I did a circumnavigation in a boat I built myself. It had a holding tank, but the simple reality was that once we left US waters, there were few pump-out stations anywhere in the world back then.
If you have considered all the issues and think a composting toilet is the answer for you...
In the freaking ocean, with all the whale poop. I have a macerator pump for overboard discharge where required or permitted. Seriously, I am not suggesting you dump sewage into a crowded anchorage somewhere.
We have a large enough holding tank for about two weeks of normal usage for two people...
Built-in bidet, too.
With all due respect to those with or considering composting toilets, what do you do when you are off serious cruising, including offshore?
Where do you dump the pee, and what do you do with the solids residue? How does this work out with the boat on its ear going to...