I did the same thing with my floor this spring. I used 60 grit on a hand sander. Then I scrubbed the living daylights out of the wood with a TSP solution, which did a good job with spilled oil/diesel.
Whoever got the bright idea that yacht floors must be teak and holly needs to be keelhauled. Teak holds up pretty well, and sanding and re-varnishing did a good job restoring it. But Holly just dry rots like nobody's business.
I just sanded as best as I could, slapped down 6 layers of varnish, and called it quits. Not as good as new by any stretch of the imagination, but a lot better than it once was. (The teak is actually golden instead of discolored grey.)
I considered bleaching, but the thought of working belowdecks with little ventilation using chemicals that harsh that need to be neutralized and rinsed off, not to mention what they'd do in the bilge, convinced me otherwise. If I personally were going to bleach the floor, I'd insist on removing it first. And if I'm going through the trouble to remove it, it'd probably be easier to use it as a pattern to make a brand new floor.
I have photos of the refinished floor here:
http://www.mackenziegems.com/gallery/tesara04 It certainly isn't perfect or like new, but it's a lot better than what it was.
Ryan Pierce, #337
