Don't sand the canvas. Unless it was impregnated with something very hard, like epoxy, sanding it would just make it fuzzy. Interestingly, that same fuzzyness makes it harder to sand further. Ever wonder why cordura nylon is more abrasion resistant than a similar weight of regular nylon pack cloth? It's the slight cushion provided by it's fuzzyness.

On a slim, efficient hull, like a kayak, skin friction is a source of drag and a natural fiber-covered boat will never have a perfectly smooth skin. It's a compromise, as are many of the things that go into the design and construction of any boat. Don't sweat it. I'll bet if you looked close enough, you could find brush strokes in the Mona Lisa too. That doesn't mean it's a bad painting.

T.E.B.

: I’ve put 2 coats of sealer-primer on the canvas of my walrus and have been
: trying to deal with the uniqueness of canvas. There are flaws in the weave
: that cause minute tuffs in the fabric. This isn’t apparent until the
: fabric is treated. I’m not concerned with the top of the boat, just the
: bottom and sides.
: I could lightly sand the sealed canvas, but I fear sanding into the fabric.
: For reason of weight, I don’t want to add any more sealant. Besides the
: increase of sealant material only makes the imperfections larger.
: Questions: Will the texture of the kayaks bottom affect perform and if so how
: much?
: Just how smooth does the bottom need to be?
: Am I correct in being paranoid of accidentally sanding into the fabric? Seams
: like the canvas rips easily. I don’t want to create any weak spots.

: Roger

: PS I’ve finished painting the top of the boat. It’s a dark teal. I used Dutch
: Boy Climate Guard Northwest 100% Acrylic Latex House Paint Semi-Gloss. The
: bottom is the same except it’s Ultra white. The Teal went on real smooth.
: I put it on very thin, so it needed 2 coats. Before Y2k+1 I’ll put on a
: 3rd coat.