The brand of epoxy isn't a big concern, so long as it's one of the "usual suspects" I'd recommend getting yours from Bateau.com - boat plans on line since 1993
as it's the cheapest going, is basically as non-blush as any A molecule can be and the 2:1 mix is easy to not screw up on. If you order by phone
, tell Joel, PAR sent you.
You'll want more thickness then 1/2" on the mahogany. A typical 1x4 would be 3.5"x.75" and you should do some scale drawing to see if this looks right, because to my eye, this sounds quite wide for a rub rail on a 27' boat. To me a 1x2 (1.5"x.75") would be more in scale with this size boat, maybe a little taller, say 2" or 2.5". As far as the thickness, you should consider 4/4th's stock (1") or better 5/4th's (1.25"). This still doesn't make me very comfortable with a hard concrete dock
and a too fast landing, but it should offer enough meat for the half oval and shoe box screws, for most of the indignation, it might endure.
Make sure you bond the fastener holes for the deck cap joint. These will act as miniature compression
posts at each fastener, preventing you from mashing the wood under too aggressive a driver. Counter sink both sides of the fastener hole on the wooden rub rail. I know this sounds crazy, but it's an old trick. This lets the bedding form a gasket
around the fastener and a much better seal as the fastener is tightened up.
For any sheer treatment like this, it's important to get both the scale and the taper right. A well done rub rail will have a taper at the ends, more at the bow then the stern. It's all about the look and some optical illusions created by prospective and curved surfaces. A well done yacht will have a "sheered" boot stripe, cove stripe (if so equipped) and tapered rub rail ends. The same is true of the wooden bulwark seen in the linked yacht. In fact on that yacht, the scale is wrong, there's isn't any taper or properly sheered bulwark or sheer strake, which to 95% of the people of the world, doesn't make a hill of beans, but to those last 5% looks novice
like and amateurish. You decide which column you'd like to be in. Do some scale sketches to see what works, for what's too big or small and remember this is a lot cheaper then having to pull everything down to shave off a 1/2" or something.
I recut a new, lowered sheer on a project
not long ago. It took all day, to get the batten in a place that I could live with, before I pulled out the fine line Sharpie and drew the cut line on the hull. I cut above the line on the follow morning and still made half a day's adjustments, to the sweep of the sheer, before I considered it ready for a sheer clamp and the other things it was to get, in this new lowered deck treatment. I mention this to suggest that playing with a sweeping curve, as important as the sheer (visually) takes a while to get just right. I looked at it from every possible angle, took breaks, asked for other opinions, and scrutinized all day, before marking the cut and this wasn't my first picnic in this arena.