@Kellan Hatch
Many thanks Keelan. I've advanced the idea a little bit more. I created that flat area for the rub rail to settle on. After removing paint and sanding I built up a flat area with epoxy+micro.
Intent-
- to sculpt a more hydrodynamic shape.
- to give the rub rail a better chance to remain in place when the inevitable knocks come along.
I laid down a strip of glass fibre right underneath the entire length of the rub rail, immersed in the wet epoxy, to tie the two pieces, the port-side epoxy and the starboard-side epoxy, together. I had a fear that the first impact would knock a ‘giant toenail clipping’ shaped piece of epoxy off my boat. Fingers crossed the fibre will keep it all tied together.

The implementation looks like this.

Obviously the fairing and painting is the next task, but first I have a choice to make. The stainless steel rub rail has adhered in place to the boat.
Q1 – Do I break this adhesion and prime+paint all surfaces, then replace the rub rail – or – do I leave the rub rail adhered in place and prime+paint only the surfaces that I have access to? My priority is to protect the plywood from salt water ingress.
@ Keelan – you’ve built a few boats, what do you think?
@ Colin – You’ve a big bundle of expertise, what do you think?
Thanks very much in advance guys,
Cheers,
Tony