One step forward . . . .
I had replaced a small spot of deck core back in 2010. To do so, I carefully cut and peeled off the top "skin" of deck fiberglass, dug out the damp balsa core, cut and planed a replacement piece out of plywood, and epoxied it all back together including the top skin. It wasn't perfect, but it was pretty good. I've been working on and off between other projects to smooth out this patch ever since.
Friday, I noticed a void in a spot at the edge of my repair. It was where I had laid some of the top skin back over good core. The easy fix was to just cut off the loose skin and fill it with fairing epoxy.
A little more grinding nearby and I discovered the truly disconcerting and bigger
Today I was cutting out my repair and digging up the damp plywood. My plywood core had fit so well, in fact, that it was touching good balsa core and dampened still more. I had to cut an inch or two wider to dig out newly damp balsa core. Arrrgghh! I usually keep a clean camp at boat yard, but as the top photo indicates I was throwing damp plywood veneers willy-nilly. With all the grinding and sanding I'd done in the meantime, it made no sense to save the top skin anymore.
I'm going back tomorrow to do a little more digging and then cut another replacement piece. I just covered it up and left in disgust tonight. I'll glass the repair in and then fair the whole thing rather than relying on the old skin for the smooth surface it ain't got anymore anyway.
This repair was several steps ago, so I don't really feel any bad continuity about steps forward vs. back. Nevertheless, it was especially frustrating as I was out shopping for paint and primer this weekend. That project has been pushed out at least week. But the work continues. A bad day hacking my boat to pieces still beats a good day at work.