I can add one more Parker observation. I had an 18' Privateer. Nice work boat but I noticed the top half of the boat was simply screwed to the hull with standard ss sheet metal screws. I am sure there was also some kind of glue between the sections, but for mechanical fastening, that was it... Sheet metal screws.
What a surprise when crawling around my Parker 1800 to see the two sections were screwed together with machine screws, and nyloc nuts. In between these fasteners were the additional sheet metal screws that attaches the rub rail. I've been boating a very long time, and this Parker never ceases to satisfy.