Originally Posted by grampianvoyager
.... Is using the fitting with just the compression lock nut not recommended?
There are many boats with throughulls such as you describe, and that's another viable method, somewhat less costly, perhaps, and simpler too - but the bigger issue there is that often those through hull fittings are not NPT/tapered threads so when you attempt to mount a threaded NPT valve on them you're lucky to get a full turn never mind several before the threads bind up.
The 'holes' used to mount the "Cadillac" fittings are not 'vulnerable' holes like the through hull itself and easy to seal when properly done.
If you peruse the rest of Maine Sail's site IIRC there's a section on the thread mismatches there too..