After hull renovation work in 2007 (see Hull Renovation Phase 1) we decided not to cover up all of that glorious mahogany, and so proceeded to apply some 10 coats of varnish.
After 4 years in the Mediterranean sun, it was clear that maintenance of the varnish was going to be problematic. We experimented with various exotic finishes; epoxy, acrylic, urethanes, natural resins, etc.
Sadly, nothing we found would avoid us having to lightly rubdown and re-coat twice each year - as were doing with the varnished deck and cabin elements.
Moreover, we could see signs of staining coming through from the seams where the copper nails came in contact with salt water. We considered making side skirts to protect from the sun, however, as we use Aramis regularly, we did not want the hassle of covering and uncovering each weekend.
Clearly there are many varnished classics sailing in the Med. However, these jewels generally have full-time maintenance crews and the finish on their bright work is normally impeccable.
You can get a feel for the environmental problem from the graph.
Even taking into account the inclination of the sun at 38°N and the relatively light colour mahogany, with summer temperatures commonly 30-35C you can see that surface temperatures of >80C would not be unusual.
On the other hand, a white hull would probably not exceed 55C.
So, with reticence, back to white it was. The recipe went something like this:
- strip back to bare wood
- West System epoxy coat (above waterline)
- surface / seams filled with Seam Compound
- 320 grit sand
- 3 coats of Yacht Primer
- 500 grit sand
- 2 coats of Pre-Kote
- 1 coat 50:50 Pre-kote / Toplac
- 2 coats of Toplac (600 grit between each)
The initial epoxy coat was to provide some resistance to minor impacts and also to improve the structure of the planks in places where the wood was somewhat friable.
The Seam Compound was specifically selected to allow for movement of the seams with temperature and humidity changes.
To ensure compatibility, we used International yacht paints and thinners throughout.
We hesitated whether or not to skim and fair the hull above the waterline, but decided against it. This was partly because of the issues that we had already seen with "plastic" coating and it also would enable a future owner to more easily revert to varnish if they so desired.
I would love to know if this expensive stuff is really that different to a quality exterior paint from your local DIY store.
The finish is reasonably good, with the planking only just visible - it is a wooden boat after all!