Circe | Wednesday, July 29, 2009

I continued my work to open the areas of the deck as required for recoring.  Yesterday, I ran out of time before I could complete the foredeck work.

This boat features a plywood reinforcement down the center portion of the foredeck, to add stiffness.  The plywood strip is thicker than the surrounding core, and protrudes below the level of the inner skin.  My sounding and test holes had revealed that the plywood was quite wet, which didn't surprise me since earlier I'd noticed water seeping out from the bottom of this area in the forward cabin.

Although I took this photo later, after I'd removed the top skin and portions of the core, the damp spot seen had been clearly visible for some time previously.

    


Before committing to cutting open a large portion of the foredeck, I first used a hole saw to create two larger inspection holes directly over the center plywood strip, both in the after half of the strip's length.  As expected, the plywood was clearly wet; I knew from my inspection that the forward half of the strip was in even worse condition, so I didn't drill any test holes there.

    

The plywood strip was 4" in width and roughly centered on the boat's centerline.  So I marked off an area 6" wide on the deck for removal--4" plus an inch on each side, to expose some of the adjacent balsa core, which I figured might also feature water problems.  Then, I cut off the skin, and removed it, revealing some badly-damaged plywood in way of the old bow cleat, and damp throughout the remaining length--though still generally structurally sound.  The plywood strip was slightly asymmetrical in relation to the boat's centerline.
    
     

It was immediately clear why the deck had cracked at the aft end of the center portion, and why water had been able to so easily and completely saturate the plywood:  the plywood was up to 1/4" shy of reaching the top skin, which had left a wide void between the fiberglass and the plywood.  At the forward end, the plywood had been in contact with, and adhered to, the fiberglass top skin, but clearly the builders had done something wrong at the aft end:  the plywood should have been even with the top of the adjacent balsa core.


I removed the exposed strips of balsa from each side of the opening; there was some water damage, but fortunately the core was clean, dry, and well-adhered at the edges of the cutout (other than the known-bad area surrounding the chainlocker vent opening on the starboard side). 

I used a large router to remove the after portion of the plywood reinforcing strip, since I had no way to really pry or chisel it out.  The router was efficient at reducing the plywood to dust.

         

With the after half removed, I found I could use a large chisel to pry up the remaining section.

    

I cleaned up the remaining plywood and core bits, and then cut away the portion of the deck around the chainlocker vent opening.  I contemplated working around the opening, but eventually cut away the raised lip, which I'd recreate later as needed/desired.  I also opened a final area requiring core attention around the port aft pulpit  base.

         

With the major surgery complete, I spent the rest of the day sanding.  First, I removed the nonskid pattern from the sidedecks and foredeck, and as far aft as the poop deck (there were modifications planned to the poop deck, so I didn't bother sanding it at this time).  Then, with the nonskid smoothed, I sanded the areas again, this time with finer paper (80) and an orbital finishing sander (vertical).  Afterwards, I ground tapers into the deck surrounding each of the areas I'd opened for the core repair, and sanded the open areas to the extent possible with the tools I had on hand at the moment.  Final preparations for the uncored areas would begin tomorrow.

         

         


Total Time Billed on This Job Today:  8 hours

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