Sanding & Fairing the Coachroof and Foredeck, and Installation of the Cockpit Well Support Bulkhead

June 29, 2019

Even with the recoring of the aft portion of the cockpit well, I decided to move forward with the installation of a small support bulkhead.  There has been some movement in the aft portion of the cockpit itself, "creaking and popping" sound coming from the general region of the boat.  It turns out, after having cut open the cockpit floor, that the balsa core was no longer in contact with the bottom skin.  As it turned out, the exercise of cutting open the cockpit floor with intentions of recoring the area was the right decision, but the need to support the aft portion of the cockpit well remained.  

I fabricated a template of the space between the hull and the bottom of the cockpit well, and then transferred that onto a piece of 9mm meranti plywood.  In a previous work session, I applied a coat of expose resin to the small bulkhead.  Today, I water-washed the amine blush from the surface and then sanded it with 80-grit paper.  The bulkhead is ready for installation.

I set the aft cockpit well supportive bulkhead to the side for now, and proceeded to work on sanding (fairing) the coachroof and the foredeck.  I had already water-washed the area from a previous work session, so I gathered my tools and materials and headed for the boat.

I used the Bosch 6" sander for the job, and used 80-grit pads.  

On a regular basis, I applied a straightedge to the surface to mark the progress in pulling high spots down to the surrounding surface, as well as marking low spots for further fairing compound application. While I was at it, I sanded the mast step and prepared it for another round of fairing compound.

With the coachroof prepped for another round of fairing compound, I turned my attention forward.  I moved my work materials to the foredeck and prepared to bring this area further into a faired surface.  The foredeck had been worked a few times already, and as a result there wasn't a heck of sanding to do. 

I quickly worked at feathering the edges in around the perimeter.  I then worked a few spots that were standing proud of the balance of the repair area.  With these few spots addressed with the 6" DA sander, I then hand sanded  a multitude of low spots that needed a good scuffing  prior to application of additional epoxy-based fairing compound.  I cleaned the surfaces, including the underside surfaces in the area of the aft cockpit well, by first vacuuming and then solvent-washing to prepare for more epoxy work.

I headed back to the shop to prepare the tabbing cuts of 1708 biaxial cloth for the installation of the small support bulkhead for the aft cockpit well.  I cut two layers forward and aft, for each side (port and starboard) of the bulkhead.  The first layer was 4" in length, the second layer being 8" in length.

I wet out the recently sanded bulkhead, as well as the surfaces within the boat to which the bulkhead and tabbing would be applied, and then installed the bulkhead.

Back in the shop, I applied epoxy resin to the aft-facing tabbing cuts and then set them aside.  I then mixed a batch of epoxy and thickened it with 406 colloidal silica and 407 low-density filler.  With the thickened epoxy, I created fillets at the intersection of the vertical bulkhead surface was the horizontal hull surfaces.  The fillet is a simply a smooth radius transition between to perpendicular surfaces to then allow the fiberglass to lay down without any voids beneath.  With the fillets applied, I then set the tabbing in place, working out any trapped air to ensure as good a surface bond as possible.

With the aft-facing tabbing in place, I then applied a layer of peel ply to the tabbing.  The peel ply will pull the amine blush through to the surface, and once  I rip off the peel ply then I'll be ready for any further epoxy work - no need for sanding!  

I repeated the steps for the forward-facing tabbing, including the peel ply.  I'll come back in the next session and remove the peel ply, and get ready to paint the area out.

I returned to the coachroof with a fresh batch of thickened epoxy.  Using a 10" and a 6" knife, I applied the fairing compound to the low spots, with the knife I dragged the material across the surface and filled the low spots as I went.  There will likely be one additional round of thickened epoxy fairing compound before she is ready for fine fairing filler (last step prior to priming).

With the coachroof done for the day, I move up to the foredeck and repeated the exercise.  Again, there wasn't as much to do on the foredeck, so I quickly worked a small cup of thickened epoxy into the remaining low spots.  It's likely that I will sand the foredeck and apply a fine fairing filler to complete the repair...and prior to paint.

Total Time Today:  5.75 hrs