Lazarette Modifications, Part 15: Final Installation of Aluminum Cockpit Hatch

The Bomar brand Aluminum Cockpit Hatch, Installed
Having completed the painting of the lazarette, it was now time for me to install the aluminum hatch that I had earlier installed temporarily in the cockpit.
Quite a bit of time had passed since I had done the original installation. Therefore, I began by checking the fit. It's difficult to tell in the picture below, but the aluminum frame did not fit firmly down into the cut-out. The forward end of the frame would not sit flush with the sole of the cockpit.
The thickened epoxy that I had used to seal the balsa core had bulged outward in some places as it had cured. I used a quarter-sheet sander with 40 grit paper to remove these bulges.
I followed up this work with a Dremel with a 50 grit sanding drum attached.
This work with these sanders did the trick. Now the frame fit well into the cutout.
Now it was time to go back and re-drill the holes. First, however, I used the countersink bit to chamfer each hole. The chamfer would allow the butyl tape to create a gasket of sorts at the top of each hole.
As far as the drilling itself was concerned, I started by using a 1/4 inch bit on each of the holes.
I was dismayed to discover voids in several of the holes that I drilled.
This had been my first stab at filling balsa core with thickened epoxy. Now I was starting to discover a few mistakes. In retrospect, I believe that my error had been in not making the thickened epoxy thick enough. The bulges here and there around the edge of the cut-out seemed to indicate that some of the epoxy that should have remained on the inside had crept to the outside. After this initial mistake, I tended make my epoxy especially thick - to a peanut butter consistency, just like everyone and every book will tell you.
I could not allow these voids to exist. They would defeat the entire purpose of my filling of the balsa core and the holes with epoxy in the first place. If water got into these voids, the untreated balsa core beyond the holes would rot.
Therefore, I had no choice but to come back and do some remedial work. I attached a 5/16 inch bit and drilled through the top skin of the fiberglass and the epoxy core for each of the problem holes. This would allow me to insert the 5/16 inch Dremel bit into the holes.
This Dremel bit would make the interior of the hole nice and wide for the acceptance of a new dose of thickened epoxy.
I used RAKA epoxy for this job, as I did for so many others on this boat.
I taped the bottom of each hole with duct tape, and then I injected each hole with neat epoxy before filling it with thickened epoxy. Two days later, I removed the duct tape from the underside of each hole. Now this cutout and its holes were properly filled.
I inserted the aluminum frame into the cutout and then stuck the drill bit through each of the pre-drilled holes in the frame. This insured that the holes in the frame matched the holes around the cutout exactly.
Then I used the countersink bit to chamfer each of the holes that I had refilled with epoxy.
In preparation for the installation of the frame, I cleaned up the area with mineral spirits. Knowing what I know now, I would have first cleaned the area with Barkeeper's Friend, a mild abrasive product that contains oxalic acid. This is what I would later use to clean this filthy cockpit area of the boat.
Then I cleaned the frame itself with acetone.
To seal the hatch frame into place, I used butyl tape that I had purchased from Maine Sail on his Compass Marine website (see the link on the homepage of my blog). This was the first of six rolls of this tape that I would use to seal up all sorts of things on Oystercatcher.
Knowing that the sole of the cockpit would be subject to much abuse, in terms of foot traffic, I put down two layers of butyl tape (instead of just one) on the flange of the frame.
As an added precaution, I wrapped the heads of the screws in butyl tape.
With everything ready, I pushed the frame into place and slowly began adding the screws, tightening them gradually here and there so that the butyl tape would distribute itself evenly.
The hatch fit well in the frame.
It looked pretty good, despite the tawdry condition of the fiberglass all around it.
I used fender washers on the underside so that the hatch frame would be as secure as possible in its new home.
Now I had just one more thing to do before I could consider this lazarette modification complete - install the hatch in the adjacent cockpit locker. This aluminum hatch would allow me to access the house battery bank. The plastic hatch in the cockpit locker would  allow me to access the reserve battery bank.
This ends this posting on how I installed the Bomar-brand aluminum hatch in the cockpit of Oystercatcher, my Ericson 25.

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