We drilled out the old rivets and so there are no new holes in her hull-deck joint. Instead I drilled the holes to 6mm the smeared epoxy filler inside. The idea is to correct for errors in hole positions, allow the machine screws to tap a thread, and seal the fibreglass. Correcting errors is important as it allows the screws to share loads when the strake is functioning as a huge chainplate for a series drogue.
I also dug out most of the old dirty mastic sealant in the hull-deck joint, finding several quite large voids on the starboard side. I sealed the gap with Sikaflex and carefully squirted plenty of extra up behind the joint and into the voids.
When the Sikaflex was tacky I folded a length of damp proof course padding in half so the fold was at the top and taped it approximately in position. The idea of this layer is to provide some protection between the hard steel and the softer fibreglass. (Also, if anyone asks what it is I can casually tell them it’s the damp proof course.)
Suspending the strakes with bungees I pierced holes in the damp proof course, squirted some Sikaflex into the holes for a final seal, and screwed in the machine screws, tapping a thread into the epoxy filler. This was good enough to hold the strake tight while I added penny washers and nyloc nuts inside the boat.
Then I trimmed off the excess damp proof course by sliding a thin piece of aluminium behind it and cutting with a knife.
Finally, I scoured the strakes with an orbital sander to clean them up and give an even light grey lustre.
Job done, ready to launch the next day.
We’ll see how it all holds up over this summer. As I mentioned before, illness will be limiting my sailing this year, so it’s very unlikely the strakes will get a thorough loading test. I’ll write about any problems that do appear on this blog.
I’m very pleased with the result so far.