New Cabin sole black water spots 2nd season. How do I fix?

[TomY]

Am I the only one that finds a varnished floor dangerous? Safety is more important than a warm glow. My floor has always been covered with well-secured carpet (larger boats--not the F-24 in my avitar, which has a textured FRP sole).

And it still looked nice when I sold it, which was nice.

There is that concern and there are a few ways to treat a clear finish with a grit for grip. The old method was to leave the sole unfinished. My original teak and holly was built that way. When I bought the boat, the sole was very grimy and was beginning to fall apart at the glue joints. I decided to restore and preserve it with a typical varnish coating. I knew below decks, varnish would hold up well and need no maintenance, easy to clean.

I skipped a grit in the finish mostly because our saloon isn't a large area and we have hand holds down throughout. If you're dealing with a broad expanse of sole to navigate, I'd be concerned, too.

As it turns out, I don't find the varnish slippery but that could be because it quickly wears to a mat finish under foot. It has some 'tooth'. It's the sheer thickness of 8 or so coats that is wearing slowly.

 

[Sailing Atlas]

I don't use epoxy under varnish so I can't help there. Certainly looks like moisture stains but I can't see it coming through the plywood from below. At any rate, be sure the boat is well ventilated, in use and off season.

The best way to get a long lasting finish on your sole pieces, is to roll and tip them. Use 4 or 6" foam rollers and disposable pans and foam brushes to tip the varnish off.

There's no way I can get as even a coating just brushing on varnish, and I've been doing a long time. Simply roll and tip your thinned coats and all full strength coats. I put on 2 or 3 thinned coats with no sanding. Then I sand between coats, sometimes just use an abrasive pad (if my base is nice and flat).

These Teak and Holly solid cabin soles were sanded and finished with 6 or 7 coats of regular gloss spar varnish in the winter of 2000. They have lost their gloss from wear, but the coating is still full and protecting the wood. The boats been heavily used in season by a family of four and two dogs.

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Beautiful example and great advice. THANKS

 

[Sailing Atlas]

Looks like black teak mildew trapped under the varnish. Varnish is NOT waterproof, epoxy is. You will need to get that varnish off and kill/bleach the mildew. When good and dry seal both sides and all edges with at least two coats of epoxy. I am partial to MAS epoxy because it is clear and has no wax blush. You can fine sand between coats to get a nice finish but I would consider using a grit additive on a sole board for slip protection. Finish with spar varnish for UV protection. A good resource for teak ply finishing is Chesapeake Light Craft - these guys have a lot of experience, and as you can see, their epoxy seal process prevents damage and staining:

thanks! LOVE the kayak